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From 3481b9883638b3aba546dd4c6e6204af0145d3dd Mon Sep 17 00:00:00 2001
From: Tor Vic <torvic9@mailbox.org>
Date: Mon, 20 Jun 2022 12:40:39 +0200
Subject: [PATCH 01/17] mm: Change dirty writeback defaults

Use a lower ratio of 5, but a longer period of 10 seconds for dirty writeback.
---
 mm/page-writeback.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index db7943999..414a9ac15 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -71,7 +71,7 @@ static long ratelimit_pages = 32;
 /*
  * Start background writeback (via writeback threads) at this percentage
  */
-static int dirty_background_ratio = 10;
+static int dirty_background_ratio = 5;
 
 /*
  * dirty_background_bytes starts at 0 (disabled) so that it is a function of
@@ -99,7 +99,7 @@ static unsigned long vm_dirty_bytes;
 /*
  * The interval between `kupdate'-style writebacks
  */
-unsigned int dirty_writeback_interval = 5 * 100; /* centiseconds */
+unsigned int dirty_writeback_interval = 10 * 100; /* centiseconds */
 
 EXPORT_SYMBOL_GPL(dirty_writeback_interval);
 
-- 
2.41.0.159.g0bfa463d37

From e57f49ce2112fbcecc666da19b52a060be0d28e2 Mon Sep 17 00:00:00 2001
From: Sultan Alsawaf <sultan@kerneltoast.com>
Date: Wed, 20 Oct 2021 20:50:11 -0700
Subject: [PATCH 02/17] ZEN: mm: Lower the non-hugetlbpage pageblock size to
 reduce scheduling delays

The page allocator processes free pages in groups of pageblocks, where
the size of a pageblock is typically quite large (1024 pages without
hugetlbpage support). Pageblocks are processed atomically with the zone
lock held, which can cause severe scheduling delays on both the CPU
going through the pageblock and any other CPUs waiting to acquire the
zone lock. A frequent offender is move_freepages_block(), which is used
by rmqueue() for page allocation.

As it turns out, there's no requirement for pageblocks to be so large,
so the pageblock order can simply be reduced to ease the scheduling
delays and zone lock contention. PAGE_ALLOC_COSTLY_ORDER is used as a
reasonable setting to ensure non-costly page allocation requests can
still be serviced without always needing to free up more than one
pageblock's worth of pages at a time.

This has a noticeable effect on overall system latency when memory
pressure is elevated. The various mm functions which operate on
pageblocks no longer appear in the preemptoff tracer, where previously
they would spend up to 100 ms on a mobile arm64 CPU processing a
pageblock with preemption disabled and the zone lock held.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
---
 include/linux/pageblock-flags.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
index e83c4c095..21b8dfa5d 100644
--- a/include/linux/pageblock-flags.h
+++ b/include/linux/pageblock-flags.h
@@ -48,7 +48,7 @@ extern unsigned int pageblock_order;
 #else /* CONFIG_HUGETLB_PAGE */
 
 /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
-#define pageblock_order		MAX_ORDER
+#define pageblock_order		PAGE_ALLOC_COSTLY_ORDER
 
 #endif /* CONFIG_HUGETLB_PAGE */
 
-- 
2.41.0.159.g0bfa463d37

From 80a9aebee4f470f0bf830acee7970bb7c7f4ee58 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Tue, 15 Nov 2022 02:46:17 +0900
Subject: [PATCH 03/17] kbuild: revive parallel execution for
 .tmp_initcalls.lds rule

Prior to commit 5d45950dfbb1 ("kbuild: move vmlinux.o link to
scripts/Makefile.vmlinux_o"), jobserver-exec was invoked from the shell
script, link-vmlinux.sh. It can get access to the jobserver because
Makefile adds '+' prefix, as in:

+$(call if_changed_dep,link_vmlinux)

Since 5d45950dfbb1, jobserver-exec is invoked from Makefile, but the
'+' prefix is missing, hence jobserver-exec has no access to the
jobserver.

Fixes: 5d45950dfbb1 ("kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_o")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
---
 scripts/Makefile.vmlinux_o | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index 0edfdb403..ae52d3b3f 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -19,7 +19,7 @@ quiet_cmd_gen_initcalls_lds = GEN     $@
 
 .tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
 		vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
-	$(call if_changed,gen_initcalls_lds)
+	+$(call if_changed,gen_initcalls_lds)
 
 targets := .tmp_initcalls.lds
 
-- 
2.41.0.159.g0bfa463d37

From fe338b1f952f8a403a912542e3c4bd6bbc5e355f Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <nathan@kernel.org>
Date: Tue, 29 Nov 2022 12:01:22 -0700
Subject: [PATCH 04/17] padata: Do not mark padata_mt_helper() as __init

When building arm64 allmodconfig + ThinLTO with clang and a proposed
modpost update to account for -ffuncton-sections, the following warning
appears:

WARNING: modpost: vmlinux.o: section mismatch in reference: padata_work_init (section: .text.padata_work_init) -> padata_mt_helper (section: .init.text)
  WARNING: modpost: vmlinux.o: section mismatch in reference: padata_work_init (section: .text.padata_work_init) -> padata_mt_helper (section: .init.text)

In both cases, an __init function calls padata_work_init(), which is not
marked __init, with padata_mt_helper(), another __init function, as a
work function argument.

padata_work_init() is called from non-init paths, otherwise it could be
marked __init to resolve the warning. Instead, remove __init from
padata_mt_helper() to resolve the warning.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 kernel/padata.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index 222d60195..b8e6b7c48 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -45,7 +45,7 @@ struct padata_mt_job_state {
 };
 
 static void padata_free_pd(struct parallel_data *pd);
-static void __init padata_mt_helper(struct work_struct *work);
+static void padata_mt_helper(struct work_struct *work);
 
 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
 {
@@ -438,7 +438,7 @@ static int padata_setup_cpumasks(struct padata_instance *pinst)
 	return err;
 }
 
-static void __init padata_mt_helper(struct work_struct *w)
+static void padata_mt_helper(struct work_struct *w)
 {
 	struct padata_work *pw = container_of(w, struct padata_work, pw_work);
 	struct padata_mt_job_state *ps = pw->pw_data;
-- 
2.41.0.159.g0bfa463d37

From d0ba6cab9113e92d5d08cabd97a30d24b6ecdcf1 Mon Sep 17 00:00:00 2001
From: Vishal Rao <vishalrao@gmail.com>
Date: Mon, 19 Dec 2022 15:34:03 +0530
Subject: [PATCH 05/17] Fix sound on ASUS Zenbook UM5302TA

---
 sound/pci/hda/cs35l41_hda.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/pci/hda/cs35l41_hda.c b/sound/pci/hda/cs35l41_hda.c
index b5210abb5..4d8936e1f 100644
--- a/sound/pci/hda/cs35l41_hda.c
+++ b/sound/pci/hda/cs35l41_hda.c
@@ -1239,7 +1239,7 @@ static int cs35l41_no_acpi_dsd(struct cs35l41_hda *cs35l41, struct device *physd
 
 	if (strncmp(hid, "CLSA0100", 8) == 0) {
 		hw_cfg->bst_type = CS35L41_EXT_BOOST_NO_VSPK_SWITCH;
-	} else if (strncmp(hid, "CLSA0101", 8) == 0) {
+	} else if (strncmp(hid, "CLSA0101", 8) == 0 || strncmp(hid, "CSC3551", 7) == 0) {
 		hw_cfg->bst_type = CS35L41_EXT_BOOST;
 		hw_cfg->gpio1.func = CS35l41_VSPK_SWITCH;
 		hw_cfg->gpio1.valid = true;
-- 
2.41.0.159.g0bfa463d37

From a949a522b6b11655207622827de28ed50850db3d Mon Sep 17 00:00:00 2001
From: Peter Jung <admin@ptr1337.dev>
Date: Thu, 29 Dec 2022 12:11:30 +0100
Subject: [PATCH 06/17] Initialize ata before graphics

ATA init is the long pole in the boot process, and its asynchronous.
move the graphics init after it so that ata and graphics initialize
in parallel

Signed-off-by: Peter Jung <admin@ptr1337.dev>
---
 drivers/Makefile | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/Makefile b/drivers/Makefile
index 7241d80a7..ac0ca3498 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -64,15 +64,8 @@ obj-y				+= char/
 # iommu/ comes before gpu as gpu are using iommu controllers
 obj-y				+= iommu/
 
-# gpu/ comes after char for AGP vs DRM startup and after iommu
-obj-y				+= gpu/
-
 obj-$(CONFIG_CONNECTOR)		+= connector/
 
-# i810fb and intelfb depend on char/agp/
-obj-$(CONFIG_FB_I810)           += video/fbdev/i810/
-obj-$(CONFIG_FB_INTEL)          += video/fbdev/intelfb/
-
 obj-$(CONFIG_PARPORT)		+= parport/
 obj-y				+= base/ block/ misc/ mfd/ nfc/
 obj-$(CONFIG_LIBNVDIMM)		+= nvdimm/
@@ -84,6 +77,14 @@ obj-y				+= macintosh/
 obj-y				+= scsi/
 obj-y				+= nvme/
 obj-$(CONFIG_ATA)		+= ata/
+
+# gpu/ comes after char for AGP vs DRM startup and after iommu
+obj-y				+= gpu/
+
+# i810fb and intelfb depend on char/agp/
+obj-$(CONFIG_FB_I810)           += video/fbdev/i810/
+obj-$(CONFIG_FB_INTEL)          += video/fbdev/intelfb/
+
 obj-$(CONFIG_TARGET_CORE)	+= target/
 obj-$(CONFIG_MTD)		+= mtd/
 obj-$(CONFIG_SPI)		+= spi/
-- 
2.41.0.159.g0bfa463d37

From f5774b412ae2f4ec4f4947bb102d5cd6cfcc0f7e Mon Sep 17 00:00:00 2001
From: Oleksandr Natalenko <oleksandr@natalenko.name>
Date: Sun, 26 Feb 2023 00:17:09 +0100
Subject: [PATCH 07/17] Bluetooth: btusb: work around command 0xfc05 tx timeout

Instead of realoding `btusb` module to tackle this:

```
Bluetooth: hci0: command 0xfc05 tx timeout
Bluetooth: hci0: Reading Intel version command failed (-110)
```

increase `btusb_qca_cmd_timeout()` sleep duration while hoping
for the best.

This looks like an ugly hack.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=215167
Signed-off-by: Oleksandr Natalenko <oleksandr@natalenko.name>
---
 drivers/bluetooth/btusb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 2a8e2bb03..c13dd7972 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -940,7 +940,7 @@ static void btusb_qca_cmd_timeout(struct hci_dev *hdev)
 		}
 
 		gpiod_set_value_cansleep(reset_gpio, 0);
-		msleep(200);
+		usleep_range(USEC_PER_SEC / 2, USEC_PER_SEC);
 		gpiod_set_value_cansleep(reset_gpio, 1);
 
 		return;
-- 
2.41.0.159.g0bfa463d37

From a331728bc37914fa035cddf567242e0ad7878272 Mon Sep 17 00:00:00 2001
From: Ian Pilcher <arequipeno@gmail.com>
Date: Tue, 27 Dec 2022 16:52:26 -0600
Subject: [PATCH 08/17] leds: trigger: Add block device LED trigger

Add "blkdev" LED trigger to blink LEDs in response to block device
activity.

Add LEDS_TRIGGER_BLKDEV (tristate) config option to control building of
the trigger.

Signed-off-by: Ian Pilcher <arequipeno@gmail.com>
Tested-by: Tor Vic <torvic9@mailbox.org> (version 12)
---
 drivers/leds/trigger/Kconfig          |    9 +
 drivers/leds/trigger/Makefile         |    1 +
 drivers/leds/trigger/ledtrig-blkdev.c | 1221 +++++++++++++++++++++++++
 3 files changed, 1231 insertions(+)
 create mode 100644 drivers/leds/trigger/ledtrig-blkdev.c

diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 2a57328ec..05e80cfd0 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -155,4 +155,13 @@ config LEDS_TRIGGER_TTY
 
 	  When build as a module this driver will be called ledtrig-tty.
 
+config LEDS_TRIGGER_BLKDEV
+	tristate "LED Trigger for block devices"
+	depends on BLOCK
+	help
+	  The blkdev LED trigger allows LEDs to be controlled by block device
+	  activity (reads and writes).
+
+	  See Documentation/leds/ledtrig-blkdev.rst.
+
 endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 25c4db97c..d53bab5d9 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+= ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_AUDIO)	+= ledtrig-audio.o
 obj-$(CONFIG_LEDS_TRIGGER_TTY)		+= ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_BLKDEV)	+= ledtrig-blkdev.o
diff --git a/drivers/leds/trigger/ledtrig-blkdev.c b/drivers/leds/trigger/ledtrig-blkdev.c
new file mode 100644
index 000000000..067eedb00
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-blkdev.c
@@ -0,0 +1,1221 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ *	Block device LED trigger
+ *
+ *	Copyright 2021-2022 Ian Pilcher <arequipeno@gmail.com>
+ */
+
+#include <linux/blkdev.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/part_stat.h>
+#include <linux/xarray.h>
+
+/**
+ * DOC: Overview
+ *
+ * The ``blkdev`` LED trigger works by periodically checking the activity
+ * counters of block devices that have been linked to one or more LEDs and
+ * blinking those LED(s) if the correct type of activity has occurred.  The
+ * periodic check is scheduled with the Linux kernel's deferred work facility.
+ *
+ * Trigger-specific data about block devices and LEDs is stored in two data
+ * structures --- &struct blkdev_trig_bdev (a "BTB") and &struct blkdev_trig_led
+ * (a "BTL").  Each structure contains a &struct xarray that holds links to any
+ * linked devices of the other type.  I.e. &blkdev_trig_bdev.linked_btls
+ * contains links to all BTLs whose LEDs have been linked to the BTB's block
+ * device, and &blkdev_trig_led.linked_btbs contains links to all BTBs whose
+ * block devices have been linked to the BTL's LED.  Thus, a block device can
+ * be linked to more than one LED, and an LED can be linked to more than one
+ * block device.
+ */
+
+/* Default, minimum & maximum blink duration (milliseconds) */
+#define BLKDEV_TRIG_BLINK_DEF	75
+#define BLKDEV_TRIG_BLINK_MIN	10
+#define BLKDEV_TRIG_BLINK_MAX	86400000  /* 24 hours */
+
+/* Default, minimum & maximum activity check interval (milliseconds) */
+#define BLKDEV_TRIG_CHECK_DEF	100
+#define BLKDEV_TRIG_CHECK_MIN	25
+#define BLKDEV_TRIG_CHECK_MAX	86400000  /* 24 hours */
+
+/*
+ * If blkdev_trig_check() can't lock the mutex, how long to wait before trying
+ * again (milliseconds)
+ */
+#define BLKDEV_TRIG_CHECK_RETRY	5
+
+/* Mode argument for calls to blkdev_get_by_path() and blkdev_put() */
+#define BLKDEV_TRIG_FMODE	0
+
+/**
+ * struct blkdev_trig_bdev - Trigger-specific data about a block device.
+ * @last_checked:	Time (in jiffies) at which the trigger last checked this
+ *			block device for activity.
+ * @last_activity:	Time (in jiffies) at which the trigger last detected
+ *			activity of each type.
+ * @ios:		Activity counter values for each type, corresponding to
+ *			the timestamps in &last_activity.
+ * @index:		&xarray index, so the BTB can be included in one or more
+ *			&blkdev_trig_led.linked_btbs.
+ * @bdev:		The block device.
+ * @linked_btls:	The BTLs that represent the LEDs linked to the BTB's
+ *			block device.
+ *
+ * Every block device linked to at least one LED gets a "BTB."  A BTB is created
+ * when a block device that is not currently linked to any LEDs is linked to an
+ * LED.
+ *
+ * A BTB is freed when one of the following occurs:
+ *
+ * * The number of LEDs linked to the block device becomes zero, because it has
+ *   been unlinked from its last LED using the trigger's &sysfs interface.
+ *
+ * * The number of LEDs linked to the block device becomes zero, because the
+ *   last LED to which it was linked has been disassociated from the trigger
+ *   (which happens automatically if the LED device is removed from the system).
+ *
+ * * The BTB's block device is removed from the system.  To accomodate this
+ *   scenario, BTB's are created as device resources, so that the release
+ *   function will be called by the driver core when the device is removed.
+ */
+struct blkdev_trig_bdev {
+	unsigned long		last_checked;
+	unsigned long		last_activity[NR_STAT_GROUPS];
+	unsigned long		ios[NR_STAT_GROUPS];
+	unsigned long		index;
+	struct block_device	*bdev;
+	struct xarray		linked_btls;
+};
+
+/**
+ * struct blkdev_trig_led - Trigger-specific data about an LED.
+ * @last_checked:	Time (in jiffies) at which the trigger last checked the
+ *			the block devices linked to this LED for activity.
+ * @index:		&xarray index, so the BTL can be included in one or more
+ *			&blkdev_trig_bdev.linked_btls.
+ * @mode:		Bitmask for types of block device activity that will
+ *			cause this LED to blink --- reads, writes, discards,
+ *			etc.
+ * @led:		The LED device.
+ * @blink_msec:		Duration of a blink (milliseconds).
+ * @check_jiffies:	Frequency with which block devices linked to this LED
+ *			should be checked for activity (jiffies).
+ * @linked_btbs:	The BTBs that represent the block devices linked to the
+ *			BTL's LED.
+ * @all_btls_node:	The BTL's node in the module's list of all BTLs.
+ *
+ * Every LED associated with the block device trigger gets a "BTL."  A BTL is
+ * created when the trigger is "activated" on an LED (usually by writing
+ * ``blkdev`` to the LED's &sysfs &trigger attribute).  A BTL is freed wnen its
+ * LED is disassociated from the trigger, either through the trigger's &sysfs
+ * interface or because the LED device is removed from the system.
+ */
+struct blkdev_trig_led {
+	unsigned long		last_checked;
+	unsigned long		index;
+	unsigned long		mode;  /* must be ulong for atomic bit ops */
+	struct led_classdev	*led;
+	unsigned int		blink_msec;
+	unsigned int		check_jiffies;
+	struct xarray		linked_btbs;
+	struct hlist_node	all_btls_node;
+};
+
+/* Protects everything except atomic LED attributes */
+static DEFINE_MUTEX(blkdev_trig_mutex);
+
+/* BTB device resource release function */
+static void blkdev_trig_btb_release(struct device *dev, void *res);
+
+/* Index for next BTB or BTL */
+static unsigned long blkdev_trig_next_index;
+
+/* All LEDs associated with the trigger */
+static HLIST_HEAD(blkdev_trig_all_btls);
+
+/* Delayed work to periodically check for activity & blink LEDs */
+static void blkdev_trig_check(struct work_struct *work);
+static DECLARE_DELAYED_WORK(blkdev_trig_work, blkdev_trig_check);
+
+/* When is the delayed work scheduled to run next (jiffies) */
+static unsigned long blkdev_trig_next_check;
+
+/* Total number of BTB-to-BTL links */
+static unsigned int blkdev_trig_link_count;
+
+/* Empty sysfs attribute list for next 2 declarations */
+static struct attribute *blkdev_trig_attrs_empty[] = { NULL };
+
+/* linked_leds sysfs directory for block devs linked to 1 or more LEDs */
+static const struct attribute_group blkdev_trig_linked_leds = {
+	.name	= "linked_leds",
+	.attrs	= blkdev_trig_attrs_empty,
+};
+
+/* linked_devices sysfs directory for each LED associated with the trigger */
+static const struct attribute_group blkdev_trig_linked_devs = {
+	.name	= "linked_devices",
+	.attrs	= blkdev_trig_attrs_empty,
+};
+
+
+/*
+ *
+ *	Delayed work to check for activity & blink LEDs
+ *
+ */
+
+/**
+ * blkdev_trig_blink() - Blink an LED, if the correct type of activity has
+ *	occurred on the block device.
+ * @btl:	The BTL that represents the LED
+ * @btb:	The BTB that represents the block device
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ * Return:	&true if the LED is blinked, &false if not.
+ */
+static bool blkdev_trig_blink(const struct blkdev_trig_led *btl,
+			      const struct blkdev_trig_bdev *btb)
+{
+	unsigned long mode, mask, delay_on, delay_off;
+	enum stat_group i;
+
+	mode = READ_ONCE(btl->mode);
+
+	for (i = STAT_READ, mask = 1; i <= STAT_FLUSH; ++i, mask <<= 1) {
+
+		if (!(mode & mask))
+			continue;
+
+		if (time_before_eq(btb->last_activity[i], btl->last_checked))
+			continue;
+
+		delay_on = READ_ONCE(btl->blink_msec);
+		delay_off = 1;	/* 0 leaves LED turned on */
+
+		led_blink_set_oneshot(btl->led, &delay_on, &delay_off, 0);
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * blkdev_trig_update_btb() - Update a BTB's activity counters and timestamps.
+ * @btb:	The BTB
+ * @now:	Timestamp (in jiffies)
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ */
+static void blkdev_trig_update_btb(struct blkdev_trig_bdev *btb,
+				   unsigned long now)
+{
+	unsigned long new_ios;
+	enum stat_group i;
+
+	for (i = STAT_READ; i <= STAT_FLUSH; ++i) {
+
+		new_ios = part_stat_read(btb->bdev, ios[i]);
+
+		if (new_ios != btb->ios[i]) {
+			btb->ios[i] = new_ios;
+			btb->last_activity[i] = now;
+		}
+	}
+
+	btb->last_checked = now;
+}
+
+/**
+ * blkdev_trig_check() - Check linked devices for activity and blink LEDs.
+ * @work:	Delayed work (&blkdev_trig_work)
+ *
+ * Context:	Process context.  Takes and releases &blkdev_trig_mutex.
+ */
+static void blkdev_trig_check(struct work_struct *work)
+{
+	struct blkdev_trig_led *btl;
+	struct blkdev_trig_bdev *btb;
+	unsigned long index, delay, now, led_check, led_delay;
+	bool blinked;
+
+	if (!mutex_trylock(&blkdev_trig_mutex)) {
+		delay = msecs_to_jiffies(BLKDEV_TRIG_CHECK_RETRY);
+		goto exit_reschedule;
+	}
+
+	now = jiffies;
+	delay = ULONG_MAX;
+
+	hlist_for_each_entry (btl, &blkdev_trig_all_btls, all_btls_node) {
+
+		led_check = btl->last_checked + btl->check_jiffies;
+
+		if (time_before_eq(led_check, now)) {
+
+			blinked = false;
+
+			xa_for_each (&btl->linked_btbs, index, btb) {
+
+				if (btb->last_checked != now)
+					blkdev_trig_update_btb(btb, now);
+				if (!blinked)
+					blinked = blkdev_trig_blink(btl, btb);
+			}
+
+			btl->last_checked = now;
+			led_delay = btl->check_jiffies;
+
+		} else {
+			led_delay = led_check - now;
+		}
+
+		if (led_delay < delay)
+			delay = led_delay;
+	}
+
+	mutex_unlock(&blkdev_trig_mutex);
+
+exit_reschedule:
+	WARN_ON_ONCE(delay == ULONG_MAX);
+	WARN_ON_ONCE(!schedule_delayed_work(&blkdev_trig_work, delay));
+}
+
+/**
+ * blkdev_trig_sched_led() - Set the schedule of the delayed work when a new
+ *	LED is added to the schedule.
+ * @btl:	The BTL that represents the LED
+ *
+ * Called when the number of block devices to which an LED is linked becomes
+ * non-zero.
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ */
+static void blkdev_trig_sched_led(const struct blkdev_trig_led *btl)
+{
+	unsigned long delay = READ_ONCE(btl->check_jiffies);
+	unsigned long check_by = jiffies + delay;
+
+	/*
+	 * If no other LED-to-block device links exist, simply schedule the
+	 * delayed work according to this LED's check_interval attribute
+	 * (check_jiffies).
+	 */
+	if (blkdev_trig_link_count == 0) {
+		WARN_ON(!schedule_delayed_work(&blkdev_trig_work, delay));
+		blkdev_trig_next_check = check_by;
+		return;
+	}
+
+	/*
+	 * If the next check is already scheduled to occur soon enough to
+	 * accomodate this LED's check_interval, the schedule doesn't need
+	 * to be changed.
+	 */
+	if (time_after_eq(check_by, blkdev_trig_next_check))
+		return;
+
+	/*
+	 * Modify the schedule, so that the delayed work runs soon enough for
+	 * this LED.
+	 */
+	WARN_ON(!mod_delayed_work(system_wq, &blkdev_trig_work, delay));
+	blkdev_trig_next_check = check_by;
+}
+
+
+/*
+ *
+ *	Linking and unlinking LEDs and block devices
+ *
+ */
+
+/**
+ * blkdev_trig_link() - Link a block device to an LED.
+ * @btl:	The BTL that represents the LED
+ * @btb:	The BTB that represents the block device
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ * Return:	&0 on success, negative &errno on error.
+ */
+static int blkdev_trig_link(struct blkdev_trig_led *btl,
+			    struct blkdev_trig_bdev *btb)
+{
+	bool led_first_link;
+	int err;
+
+	led_first_link = xa_empty(&btl->linked_btbs);
+
+	err = xa_insert(&btb->linked_btls, btl->index, btl, GFP_KERNEL);
+	if (err)
+		return err;
+
+	err = xa_insert(&btl->linked_btbs, btb->index, btb, GFP_KERNEL);
+	if (err)
+		goto error_erase_btl;
+
+	/* Create /sys/class/block/<bdev>/linked_leds/<led> symlink */
+	err = sysfs_add_link_to_group(bdev_kobj(btb->bdev),
+				      blkdev_trig_linked_leds.name,
+				      &btl->led->dev->kobj, btl->led->name);
+	if (err)
+		goto error_erase_btb;
+
+	/* Create /sys/class/leds/<led>/linked_devices/<bdev> symlink */
+	err = sysfs_add_link_to_group(&btl->led->dev->kobj,
+				      blkdev_trig_linked_devs.name,
+				      bdev_kobj(btb->bdev),
+				      dev_name(&btb->bdev->bd_device));
+	if (err)
+		goto error_remove_symlink;
+
+	/*
+	 * If this is the first block device linked to this LED, the delayed
+	 * work schedule may need to be changed.
+	 */
+	if (led_first_link)
+		blkdev_trig_sched_led(btl);
+
+	++blkdev_trig_link_count;
+
+	return 0;
+
+error_remove_symlink:
+	sysfs_remove_link_from_group(bdev_kobj(btb->bdev),
+				     blkdev_trig_linked_leds.name,
+				     btl->led->name);
+error_erase_btb:
+	xa_erase(&btl->linked_btbs, btb->index);
+error_erase_btl:
+	xa_erase(&btb->linked_btls, btl->index);
+	return err;
+}
+
+/**
+ * blkdev_trig_put_btb() - Remove and free a BTB, if it is no longer needed.
+ * @btb:	The BTB
+ *
+ * Does nothing if the BTB (block device) is still linked to at least one LED.
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ */
+static void blkdev_trig_put_btb(struct blkdev_trig_bdev *btb)
+{
+	struct block_device *bdev = btb->bdev;
+	int err;
+
+	if (xa_empty(&btb->linked_btls)) {
+
+		sysfs_remove_group(bdev_kobj(bdev), &blkdev_trig_linked_leds);
+		err = devres_destroy(&bdev->bd_device, blkdev_trig_btb_release,
+				     NULL, NULL);
+		WARN_ON(err);
+	}
+}
+
+/**
+ * _blkdev_trig_unlink_always() - Perform the unconditionally required steps of
+ *	unlinking a block device from an LED.
+ * @btl:	The BTL that represents the LED
+ * @btb:	The BTB that represents the block device
+ *
+ * When a block device is unlinked from an LED, certain steps must be performed
+ * only if the block device is **not** being released.  This function performs
+ * those steps that are **always** required, whether or not the block device is
+ * being released.
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ */
+static void _blkdev_trig_unlink_always(struct blkdev_trig_led *btl,
+				       struct blkdev_trig_bdev *btb)
+{
+	--blkdev_trig_link_count;
+
+	if (blkdev_trig_link_count == 0)
+		WARN_ON(!cancel_delayed_work_sync(&blkdev_trig_work));
+
+	xa_erase(&btb->linked_btls, btl->index);
+	xa_erase(&btl->linked_btbs, btb->index);
+
+	/* Remove /sys/class/leds/<led>/linked_devices/<bdev> symlink */
+	sysfs_remove_link_from_group(&btl->led->dev->kobj,
+				     blkdev_trig_linked_devs.name,
+				     dev_name(&btb->bdev->bd_device));
+}
+
+/**
+ * blkdev_trig_unlink_norelease() - Unlink an LED from a block device that is
+ *	**not** being released.
+ * @btl:	The BTL that represents the LED.
+ * @btb:	The BTB that represents the block device.
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ */
+static void blkdev_trig_unlink_norelease(struct blkdev_trig_led *btl,
+					 struct blkdev_trig_bdev *btb)
+{
+	_blkdev_trig_unlink_always(btl, btb);
+
+	/* Remove /sys/class/block/<bdev>/linked_leds/<led> symlink */
+	sysfs_remove_link_from_group(bdev_kobj(btb->bdev),
+				     blkdev_trig_linked_leds.name,
+				     btl->led->name);
+
+	blkdev_trig_put_btb(btb);
+}
+
+/**
+ * blkdev_trig_unlink_release() - Unlink an LED from a block device that is
+ *	being released.
+ * @btl:	The BTL that represents the LED
+ * @btb:	The BTB that represents the block device
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ */
+static void blkdev_trig_unlink_release(struct blkdev_trig_led *btl,
+				       struct blkdev_trig_bdev *btb)
+{
+	_blkdev_trig_unlink_always(btl, btb);
+
+	/*
+	 * If the BTB is being released, the driver core has already removed the
+	 * device's attribute groups, and the BTB will be freed automatically,
+	 * so there's nothing else to do.
+	 */
+}
+
+
+/*
+ *
+ *	BTB creation
+ *
+ */
+
+/**
+ * blkdev_trig_btb_release() - BTB device resource release function.
+ * @dev:	The block device
+ * @res:	The BTB
+ *
+ * Called by the driver core when a block device with a BTB is removed.
+ *
+ * Context:	Process context.  Takes and releases &blkdev_trig_mutex.
+ */
+static void blkdev_trig_btb_release(struct device *dev, void *res)
+{
+	struct blkdev_trig_bdev *btb = res;
+	struct blkdev_trig_led *btl;
+	unsigned long index;
+
+	mutex_lock(&blkdev_trig_mutex);
+
+	xa_for_each (&btb->linked_btls, index, btl)
+		blkdev_trig_unlink_release(btl, btb);
+
+	mutex_unlock(&blkdev_trig_mutex);
+}
+
+/**
+ * blkdev_trig_get_bdev() - Get a block device by path.
+ * @path:	The value written to an LED's &link_dev_by_path or
+ *		&unlink_dev_by_path attribute, which should be the path to a
+ *		special file that represents a block device
+ * @len:	The number of characters in &path (not including its
+ *		terminating null)
+ *
+ * The caller must call blkdev_put() when finished with the device.
+ *
+ * Context:	Process context.
+ * Return:	The block device, or an error pointer.
+ */
+static struct block_device *blkdev_trig_get_bdev(const char *path, size_t len)
+{
+	struct block_device *bdev;
+	char *buf;
+
+	buf = kmemdup(path, len + 1, GFP_KERNEL);  /* +1 to include null */
+	if (buf == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	bdev = blkdev_get_by_path(strim(buf), BLKDEV_TRIG_FMODE, THIS_MODULE);
+	kfree(buf);
+	return bdev;
+}
+
+/**
+ * blkdev_trig_get_btb() - Find or create the BTB for a block device.
+ * @path:	The value written to an LED's &link_dev_by_path attribute,
+ *		which should be the path to a special file that represents a
+ *		block device
+ * @len:	The number of characters in &path
+ *
+ * If a new BTB is created, because the block device was not previously linked
+ * to any LEDs, the block device's &linked_leds &sysfs directory is created.
+ *
+ * Context:	Process context.  Caller must hold &blkdev_trig_mutex.
+ * Return:	Pointer to the BTB, error pointer on error.
+ */
+static struct blkdev_trig_bdev *blkdev_trig_get_btb(const char *path,
+						    size_t len)
+{
+	struct block_device *bdev;
+	struct blkdev_trig_bdev *btb;
+	int err;
+
+	bdev = blkdev_trig_get_bdev(path, len);
+	if (IS_ERR(bdev))
+		return ERR_CAST(bdev);
+
+	btb = devres_find(&bdev->bd_device, blkdev_trig_btb_release,
+			  NULL, NULL);
+	if (btb != NULL) {
+		err = 0;
+		goto exit_put_bdev;
+	}
+
+	if (blkdev_trig_next_index == ULONG_MAX) {
+		err = -EOVERFLOW;
+		goto exit_put_bdev;
+	}
+
+	btb = devres_alloc(blkdev_trig_btb_release, sizeof(*btb), GFP_KERNEL);
+	if (btb == NULL) {
+		err = -ENOMEM;
+		goto exit_put_bdev;
+	}
+
+	err = sysfs_create_group(bdev_kobj(bdev), &blkdev_trig_linked_leds);
+	if (err)
+		goto exit_free_btb;
+
+	btb->index = blkdev_trig_next_index++;
+	btb->bdev = bdev;
+	xa_init(&btb->linked_btls);
+
+	/* Populate BTB activity counters */
+	blkdev_trig_update_btb(btb, jiffies);
+
+	devres_add(&bdev->bd_device, btb);
+
+exit_free_btb:
+	if (err)
+		devres_free(btb);
+exit_put_bdev:
+	blkdev_put(bdev, BLKDEV_TRIG_FMODE);
+	return err ? ERR_PTR(err) : btb;
+}
+
+
+/*
+ *
+ *	Activating and deactivating the trigger on an LED
+ *
+ */
+
+/**
+ * blkdev_trig_activate() - Called by the LEDs subsystem when an LED is
+ *	associated with the trigger.
+ * @led:	The LED
+ *
+ * Context:	Process context.  Takes and releases &blkdev_trig_mutex.
+ * Return:	&0 on success, negative &errno on error.
+ */
+static int blkdev_trig_activate(struct led_classdev *led)
+{
+	struct blkdev_trig_led *btl;
+	int err;
+
+	btl = kzalloc(sizeof(*btl), GFP_KERNEL);
+	if (btl == NULL)
+		return -ENOMEM;
+
+	err = mutex_lock_interruptible(&blkdev_trig_mutex);
+	if (err)
+		goto exit_free;
+
+	if (blkdev_trig_next_index == ULONG_MAX) {
+		err = -EOVERFLOW;
+		goto exit_unlock;
+	}
+
+	btl->index = blkdev_trig_next_index++;
+	btl->last_checked = jiffies;
+	btl->mode = -1;  /* set all bits */
+	btl->led = led;
+	btl->blink_msec = BLKDEV_TRIG_BLINK_DEF;
+	btl->check_jiffies = msecs_to_jiffies(BLKDEV_TRIG_CHECK_DEF);
+	xa_init(&btl->linked_btbs);
+
+	hlist_add_head(&btl->all_btls_node, &blkdev_trig_all_btls);
+	led_set_trigger_data(led, btl);
+
+exit_unlock:
+	mutex_unlock(&blkdev_trig_mutex);
+exit_free:
+	if (err)
+		kfree(btl);
+	return err;
+}
+
+/**
+ * blkdev_trig_deactivate() - Called by the the LEDs subsystem when an LED is
+ *	disassociated from the trigger.
+ * @led:	The LED
+ *
+ * The LEDs subsystem also calls this function when an LED associated with the
+ * trigger is removed or when the trigger is unregistered (if the module is
+ * unloaded).
+ *
+ * Context:	Process context.  Takes and releases &blkdev_trig_mutex.
+ */
+static void blkdev_trig_deactivate(struct led_classdev *led)
+{
+	struct blkdev_trig_led *btl = led_get_trigger_data(led);
+	struct blkdev_trig_bdev *btb;
+	unsigned long index;
+
+	mutex_lock(&blkdev_trig_mutex);
+
+	xa_for_each (&btl->linked_btbs, index, btb)
+		blkdev_trig_unlink_norelease(btl, btb);
+
+	hlist_del(&btl->all_btls_node);
+	kfree(btl);
+
+	mutex_unlock(&blkdev_trig_mutex);
+}
+
+
+/*
+ *
+ *	Link-related attribute store functions
+ *
+ */
+
+/**
+ * link_dev_by_path_store() - &link_dev_by_path device attribute store function.
+ * @dev:	The LED device
+ * @attr:	The &link_dev_by_path attribute (&dev_attr_link_dev_by_path)
+ * @buf:	The value written to the attribute, which should be the path to
+ *		a special file that represents a block device to be linked to
+ *		the LED (e.g. ``/dev/sda``)
+ * @count:	The number of characters in &buf
+ *
+ * Context:	Process context.  Takes and releases &blkdev_trig_mutex.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t link_dev_by_path_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct blkdev_trig_led *btl = led_trigger_get_drvdata(dev);
+	struct blkdev_trig_bdev *btb;
+	int err;
+
+	err = mutex_lock_interruptible(&blkdev_trig_mutex);
+	if (err)
+		return err;
+
+	btb = blkdev_trig_get_btb(buf, count);
+	if (IS_ERR(btb)) {
+		err = PTR_ERR(btb);
+		goto exit_unlock;
+	}
+
+	if (xa_load(&btb->linked_btls, btl->index) != NULL) {
+		err = -EEXIST;
+		goto exit_put_btb;
+	}
+
+	err = blkdev_trig_link(btl, btb);
+
+exit_put_btb:
+	if (err)
+		blkdev_trig_put_btb(btb);
+exit_unlock:
+	mutex_unlock(&blkdev_trig_mutex);
+	return err ? : count;
+}
+
+/**
+ * unlink_dev_by_path_store() - &unlink_dev_by_path device attribute store
+ *	function.
+ * @dev:	The LED device
+ * @attr:	The &unlink_dev_by_path attribute (&dev_attr_unlink_dev_by_path)
+ * @buf:	The value written to the attribute, which should be the path to
+ *		a special file that represents a block device to be unlinked
+ *		from the LED (e.g. ``/dev/sda``)
+ * @count:	The number of characters in &buf
+ *
+ * Context:	Process context.  Takes and releases &blkdev_trig_mutex.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t unlink_dev_by_path_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct blkdev_trig_led *btl = led_trigger_get_drvdata(dev);
+	struct block_device *bdev;
+	struct blkdev_trig_bdev *btb;
+	int err;
+
+	bdev = blkdev_trig_get_bdev(buf, count);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
+
+	err = mutex_lock_interruptible(&blkdev_trig_mutex);
+	if (err)
+		goto exit_put_bdev;
+
+	btb = devres_find(&bdev->bd_device, blkdev_trig_btb_release,
+			  NULL, NULL);
+	if (btb == NULL) {
+		err = -EUNATCH;  /* bdev isn't linked to any LED */
+		goto exit_unlock;
+	}
+
+	if (xa_load(&btb->linked_btls, btl->index) == NULL) {
+		err = -EUNATCH;  /* bdev isn't linked to this LED */
+		goto exit_unlock;
+	}
+
+	blkdev_trig_unlink_norelease(btl, btb);
+
+exit_unlock:
+	mutex_unlock(&blkdev_trig_mutex);
+exit_put_bdev:
+	blkdev_put(bdev, BLKDEV_TRIG_FMODE);
+	return err ? : count;
+}
+
+/**
+ * unlink_dev_by_name_store() - &unlink_dev_by_name device attribute store
+ *	function.
+ * @dev:	The LED device
+ * @attr:	The &unlink_dev_by_name attribute (&dev_attr_unlink_dev_by_name)
+ * @buf:	The value written to the attribute, which should be the kernel
+ *		name of a block device to be unlinked from the LED (e.g.
+ *		``sda``)
+ * @count:	The number of characters in &buf
+ *
+ * Context:	Process context.  Takes and releases &blkdev_trig_mutex.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t unlink_dev_by_name_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct blkdev_trig_led *btl = led_trigger_get_drvdata(dev);
+	struct blkdev_trig_bdev *btb;
+	unsigned long index;
+	int err;
+
+	err = mutex_lock_interruptible(&blkdev_trig_mutex);
+	if (err)
+		return err;
+
+	err = -EUNATCH;
+
+	xa_for_each (&btl->linked_btbs, index, btb) {
+
+		if (sysfs_streq(dev_name(&btb->bdev->bd_device), buf)) {
+			blkdev_trig_unlink_norelease(btl, btb);
+			err = 0;
+			break;
+		}
+	}
+
+	mutex_unlock(&blkdev_trig_mutex);
+	return err ? : count;
+}
+
+
+/*
+ *
+ *	Atomic attribute show & store functions
+ *
+ */
+
+/**
+ * blink_time_show() - &blink_time device attribute show function.
+ * @dev:	The LED device
+ * @attr:	The &blink_time attribute (&dev_attr_blink_time)
+ * @buf:	Output buffer
+ *
+ * Writes the value of &blkdev_trig_led.blink_msec to &buf.
+ *
+ * Context:	Process context.
+ * Return:	The number of characters written to &buf.
+ */
+static ssize_t blink_time_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	const struct blkdev_trig_led *btl = led_trigger_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", READ_ONCE(btl->blink_msec));
+}
+
+/**
+ * blink_time_store() - &blink_time device attribute store function.
+ * @dev:	The LED device
+ * @attr:	The &blink_time attribute (&dev_attr_blink_time)
+ * @buf:	The new value (as written to the &sysfs attribute)
+ * @count:	The number of characters in &buf
+ *
+ * Sets &blkdev_trig_led.blink_msec to the value in &buf.
+ *
+ * Context:	Process context.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t blink_time_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct blkdev_trig_led *btl = led_trigger_get_drvdata(dev);
+	unsigned int value;
+	int err;
+
+	err = kstrtouint(buf, 0, &value);
+	if (err)
+		return err;
+
+	if (value < BLKDEV_TRIG_BLINK_MIN || value > BLKDEV_TRIG_BLINK_MAX)
+		return -ERANGE;
+
+	WRITE_ONCE(btl->blink_msec, value);
+	return count;
+}
+
+/**
+ * check_interval_show() - &check_interval device attribute show function.
+ * @dev:	The LED device
+ * @attr:	The &check_interval attribute (&dev_attr_check_interval)
+ * @buf:	Output buffer
+ *
+ * Writes the value of &blkdev_trig_led.check_jiffies (converted to
+ * milliseconds) to &buf.
+ *
+ * Context:	Process context.
+ * Return:	The number of characters written to &buf.
+ */
+static ssize_t check_interval_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct blkdev_trig_led *btl = led_trigger_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n",
+			  jiffies_to_msecs(READ_ONCE(btl->check_jiffies)));
+}
+
+/**
+ * check_interval_store() - &check_interval device attribute store function
+ * @dev:	The LED device
+ * @attr:	The &check_interval attribute (&dev_attr_check_interval)
+ * @buf:	The new value (as written to the &sysfs attribute)
+ * @count:	The number of characters in &buf
+ *
+ * Sets &blkdev_trig_led.check_jiffies to the value in &buf (after converting
+ * from milliseconds).
+ *
+ * Context:	Process context.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t check_interval_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	struct blkdev_trig_led *led = led_trigger_get_drvdata(dev);
+	unsigned int value;
+	int err;
+
+	err = kstrtouint(buf, 0, &value);
+	if (err)
+		return err;
+
+	if (value < BLKDEV_TRIG_CHECK_MIN || value > BLKDEV_TRIG_CHECK_MAX)
+		return -ERANGE;
+
+	WRITE_ONCE(led->check_jiffies, msecs_to_jiffies(value));
+
+	return count;
+}
+
+/**
+ * blkdev_trig_mode_show() - Helper for boolean attribute show functions.
+ * @led:	The LED
+ * @buf:	Output buffer
+ * @bit:	Which bit to show
+ *
+ * Context:	Process context.
+ * Return:	The number of characters written to &buf.
+ */
+static int blkdev_trig_mode_show(const struct blkdev_trig_led *led, char *buf,
+				 enum stat_group bit)
+{
+	return sysfs_emit(buf,
+			  READ_ONCE(led->mode) & (1 << bit) ? "Y\n" : "N\n");
+}
+
+/**
+ * blkdev_trig_mode_store() - Helper for boolean attribute store functions.
+ * @led:	The LED
+ * @buf:	The new value (as written to the &sysfs attribute)
+ * @count:	The number of characters in &buf
+ * @bit:	Which bit to set
+ *
+ * Context:	Process context.
+ * Return:	&count on success, negative &errno on error.
+ */
+static int blkdev_trig_mode_store(struct blkdev_trig_led *led,
+				  const char *buf, size_t count,
+				  enum stat_group bit)
+{
+	bool set;
+	int err;
+
+	err = kstrtobool(buf, &set);
+	if (err)
+		return err;
+
+	if (set)
+		set_bit(bit, &led->mode);
+	else
+		clear_bit(bit, &led->mode);
+
+	return count;
+}
+
+/**
+ * blink_on_read_show() - &blink_on_read device attribute show function.
+ * @dev:	The LED device
+ * @attr:	The &blink_on_read attribute (&dev_attr_blink_on_read)
+ * @buf:	Output buffer
+ *
+ * Writes ``Y`` or ``N`` to &buf, depending on whether the &STAT_READ bit in
+ * &blkdev_trig_led.mode is set or cleared.
+ *
+ * Context:	Process context.
+ * Return:	The number of characters written to &buf.
+ */
+static ssize_t blink_on_read_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	return blkdev_trig_mode_show(led_trigger_get_drvdata(dev),
+				     buf, STAT_READ);
+}
+
+/**
+ * blink_on_read_store() - &blink_on_read device attribute store function.
+ * @dev:	The LED device
+ * @attr:	The &blink_on_read attribute (&dev_attr_blink_on_read)
+ * @buf:	The new value (as written to the &sysfs attribute)
+ * @count:	The number of characters in &buf
+ *
+ * Sets the &STAT_READ bit in &blkdev_trig_led.mode to the value in &buf
+ * (interpretted as a boolean).
+ *
+ * Context:	Process context.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t blink_on_read_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	return blkdev_trig_mode_store(led_trigger_get_drvdata(dev),
+				      buf, count, STAT_READ);
+}
+
+/**
+ * blink_on_write_show() - &blink_on_write device attribute show function.
+ * @dev:	The LED device
+ * @attr:	The &blink_on_write attribute (&dev_attr_blink_on_write)
+ * @buf:	Output buffer
+ *
+ * Writes ``Y`` or ``N`` to &buf, depending on whether the &STAT_WRITE bit in
+ * in &blkdev_trig_led.mode is set or cleared.
+ *
+ * Context:	Process context.
+ * Return:	The number of characters written to &buf.
+ */
+static ssize_t blink_on_write_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	return blkdev_trig_mode_show(led_trigger_get_drvdata(dev),
+				     buf, STAT_WRITE);
+}
+
+/**
+ * blink_on_write_store() - &blink_on_write device attribute store function.
+ * @dev:	The LED device
+ * @attr:	The &blink_on_write attribute (&dev_attr_blink_on_write)
+ * @buf:	The new value (as written to the &sysfs attribute)
+ * @count:	The number of characters in &buf
+ *
+ * Sets the &STAT_WRITE bit in &blkdev_trig_led.mode to the value in &buf
+ * (interpretted as a boolean).
+ *
+ * Context:	Process context.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t blink_on_write_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	return blkdev_trig_mode_store(led_trigger_get_drvdata(dev),
+				      buf, count, STAT_WRITE);
+}
+
+/**
+ * blink_on_flush_show() - &blink_on_flush device attribute show function.
+ * @dev:	The LED device
+ * @attr:	The &blink_on_flush attribute (&dev_attr_blink_on_flush)
+ * @buf:	Output buffer
+ *
+ * Writes ``Y`` or ``N`` to &buf, depending whether the &STAT_FLUSH bit in
+ * &blkdev_trig_led.mode is set or cleared.
+ *
+ * Context:	Process context.
+ * Return:	The number of characters written to &buf.
+ */
+static ssize_t blink_on_flush_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	return blkdev_trig_mode_show(led_trigger_get_drvdata(dev),
+				     buf, STAT_FLUSH);
+}
+
+/**
+ * blink_on_flush_store() - &blink_on_flush device attribute store function.
+ * @dev:	The LED device
+ * @attr:	The &blink_on_flush attribute (&dev_attr_blink_on_flush)
+ * @buf:	The new value (as written to the &sysfs attribute)
+ * @count:	The number of characters in &buf
+ *
+ * Sets the &STAT_FLUSH bit in &blkdev_trig_led.mode to the value in &buf
+ * (interpretted as a boolean).
+ *
+ * Context:	Process context.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t blink_on_flush_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	return blkdev_trig_mode_store(led_trigger_get_drvdata(dev),
+				      buf, count, STAT_FLUSH);
+}
+
+/**
+ * blink_on_discard_show() - &blink_on_discard device attribute show function.
+ * @dev:	The LED device
+ * @attr:	The &blink_on_discard attribute (&dev_attr_blink_on_discard)
+ * @buf:	Output buffer
+ *
+ * Writes ``Y`` or ``N`` to &buf, depending on whether the &STAT_DISCARD bit in
+ * &blkdev_trig_led.mode is set or cleared.
+ *
+ * Context:	Process context.
+ * Return:	The number of characters written to &buf.
+ */
+static ssize_t blink_on_discard_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	return blkdev_trig_mode_show(led_trigger_get_drvdata(dev),
+				     buf, STAT_DISCARD);
+}
+
+/**
+ * blink_on_discard_store() - &blink_on_discard device attribute store function.
+ * @dev:	The LED device
+ * @attr:	The &blink_on_discard attribute (&dev_attr_blink_on_discard)
+ * @buf:	The new value (as written to the &sysfs attribute)
+ * @count:	The number of characters in &buf
+ *
+ * Sets the &STAT_DISCARD bit in &blkdev_trig_led.mode to the value in &buf
+ * (interpretted as a boolean).
+ *
+ * Context:	Process context.
+ * Return:	&count on success, negative &errno on error.
+ */
+static ssize_t blink_on_discard_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	return blkdev_trig_mode_store(led_trigger_get_drvdata(dev),
+				      buf, count, STAT_DISCARD);
+}
+
+/* Device attributes */
+static DEVICE_ATTR_WO(link_dev_by_path);
+static DEVICE_ATTR_WO(unlink_dev_by_path);
+static DEVICE_ATTR_WO(unlink_dev_by_name);
+static DEVICE_ATTR_RW(blink_time);
+static DEVICE_ATTR_RW(check_interval);
+static DEVICE_ATTR_RW(blink_on_read);
+static DEVICE_ATTR_RW(blink_on_write);
+static DEVICE_ATTR_RW(blink_on_flush);
+static DEVICE_ATTR_RW(blink_on_discard);
+
+/* Device attributes in LED directory (/sys/class/leds/<led>/...) */
+static struct attribute *blkdev_trig_attrs[] = {
+	&dev_attr_link_dev_by_path.attr,
+	&dev_attr_unlink_dev_by_path.attr,
+	&dev_attr_unlink_dev_by_name.attr,
+	&dev_attr_blink_time.attr,
+	&dev_attr_check_interval.attr,
+	&dev_attr_blink_on_read.attr,
+	&dev_attr_blink_on_write.attr,
+	&dev_attr_blink_on_flush.attr,
+	&dev_attr_blink_on_discard.attr,
+	NULL
+};
+
+/* Unnamed attribute group == no subdirectory */
+static const struct attribute_group blkdev_trig_attr_group = {
+	.attrs	= blkdev_trig_attrs,
+};
+
+/* Attribute groups for the trigger */
+static const struct attribute_group *blkdev_trig_attr_groups[] = {
+	&blkdev_trig_attr_group,   /* /sys/class/leds/<led>/... */
+	&blkdev_trig_linked_devs,  /* /sys/class/leds/<led>/linked_devices/ */
+	NULL
+};
+
+/* Trigger registration data */
+static struct led_trigger blkdev_trig_trigger = {
+	.name		= "blkdev",
+	.activate	= blkdev_trig_activate,
+	.deactivate	= blkdev_trig_deactivate,
+	.groups		= blkdev_trig_attr_groups,
+};
+
+/**
+ * blkdev_trig_init() - Block device LED trigger initialization.
+ *
+ * Registers the ``blkdev`` LED trigger.
+ *
+ * Return:	&0 on success, negative &errno on failure.
+ */
+static int __init blkdev_trig_init(void)
+{
+	return led_trigger_register(&blkdev_trig_trigger);
+}
+module_init(blkdev_trig_init);
+
+/**
+ * blkdev_trig_exit() - Block device LED trigger module exit.
+ *
+ * Unregisters the ``blkdev`` LED trigger.
+ */
+static void __exit blkdev_trig_exit(void)
+{
+	led_trigger_unregister(&blkdev_trig_trigger);
+}
+module_exit(blkdev_trig_exit);
+
+MODULE_DESCRIPTION("Block device LED trigger");
+MODULE_AUTHOR("Ian Pilcher <arequipeno@gmail.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.41.0.159.g0bfa463d37

From b9c32fbfdd7f2b8ff8cd8a9539195240e1a8971f Mon Sep 17 00:00:00 2001
From: Ian Pilcher <arequipeno@gmail.com>
Date: Tue, 27 Dec 2022 16:52:25 -0600
Subject: [PATCH 09/17] docs: Add block device (blkdev) LED trigger
 documentation

Add Documentation/ABI/testing/sysfs-class-led-trigger-blkdev to
document:

* /sys/class/leds/<led>/blink_time
  * /sys/class/leds/<led>/check_interval
  * /sys/class/leds/<led>/blink_on_{read,write,discard,flush}
  * /sys/class/leds/<led>/link_dev_by_path
  * /sys/class/leds/<led>/unlink_dev_by_path
  * /sys/class/leds/<led>/unlink_dev_by_name
  * /sys/class/leds/<led>/linked_devices

Add /sys/block/<disk>/linked_leds to
Documentation/ABI/stable/sysfs-block.

Add overview in Documentation/leds/ledtrig-blkdev.rst.

Signed-off-by: Ian Pilcher <arequipeno@gmail.com>
---
 Documentation/ABI/stable/sysfs-block          |  10 ++
 .../testing/sysfs-class-led-trigger-blkdev    |  78 +++++++++
 Documentation/leds/index.rst                  |   1 +
 Documentation/leds/ledtrig-blkdev.rst         | 158 ++++++++++++++++++
 4 files changed, 247 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-blkdev
 create mode 100644 Documentation/leds/ledtrig-blkdev.rst

diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block
index c57e5b7cb..2d1df6c9b 100644
--- a/Documentation/ABI/stable/sysfs-block
+++ b/Documentation/ABI/stable/sysfs-block
@@ -101,6 +101,16 @@ Description:
 		devices that support receiving integrity metadata.
 
 
+What:		/sys/block/<disk>/linked_leds
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Directory that contains symbolic links to all LEDs that
+		are associated with (linked to) this block device by the
+		blkdev LED trigger.  Only present when at least one LED
+		is linked.  (See Documentation/leds/ledtrig-blkdev.rst.)
+
+
 What:		/sys/block/<disk>/<partition>/alignment_offset
 Date:		April 2009
 Contact:	Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-blkdev b/Documentation/ABI/testing/sysfs-class-led-trigger-blkdev
new file mode 100644
index 000000000..28ce8c814
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-blkdev
@@ -0,0 +1,78 @@
+What:		/sys/class/leds/<led>/blink_time
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Time (in milliseconds) that the LED will be on during a single
+		"blink".
+
+What:		/sys/class/leds/<led>/check_interval
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Interval (in milliseconds) between checks of the block devices
+		linked to this LED.  The LED will be blinked if the correct type
+		of activity (see blink_on_{read,write,discard,flush} attributes)
+		has occurred on any of the linked devices since the previous
+		check.
+
+What:		/sys/class/leds/<led>/blink_on_read
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Boolean that determines whether the LED will blink in response
+		to read activity on any of its linked block devices.
+
+What:		/sys/class/leds/<led>/blink_on_write
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Boolean that determines whether the LED will blink in response
+		to write activity on any of its linked block devices.
+
+What:		/sys/class/leds/<led>/blink_on_discard
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Boolean that determines whether the LED will blink in response
+		to discard activity on any of its linked block devices.
+
+What:		/sys/class/leds/<led>/blink_on_flush
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gamil.com>
+Description:
+		Boolean that determines whether the LED will blink in response
+		to cache flush activity on any of its linked block devices.
+
+What:		/sys/class/leds/<led>/link_dev_by_path
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Associate a block device with this LED by writing the path to
+		the device special file (e.g. /dev/sda) to this attribute.
+		Symbolic links are followed.
+
+What:		/sys/class/leds/<led>/unlink_dev_by_path
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Remove the association between this LED and a block device by
+		writing the path to the device special file (e.g. /dev/sda) to
+		this attribute.  Symbolic links are followed.
+
+What:		/sys/class/leds/<led>/unlink_dev_by_name
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Remove the association between this LED and a block device by
+		writing the kernel name of the device (e.g. sda) to this
+		attribute.
+
+What:		/sys/class/leds/<led>/linked_devices
+Date:		January 2023
+Contact:	Ian Pilcher <arequipeno@gmail.com>
+Description:
+		Directory containing links to all block devices that are
+		associated with this LED.  (Note that the names of the
+		symbolic links in this directory are *kernel* names, which
+		may not match the device special file paths written to
+		link_device and unlink_device.)
diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst
index ce57254cb..bcbd55bf1 100644
--- a/Documentation/leds/index.rst
+++ b/Documentation/leds/index.rst
@@ -10,6 +10,7 @@ LEDs
    leds-class
    leds-class-flash
    leds-class-multicolor
+   ledtrig-blkdev
    ledtrig-oneshot
    ledtrig-transient
    ledtrig-usbport
diff --git a/Documentation/leds/ledtrig-blkdev.rst b/Documentation/leds/ledtrig-blkdev.rst
new file mode 100644
index 000000000..9ff5b99de
--- /dev/null
+++ b/Documentation/leds/ledtrig-blkdev.rst
@@ -0,0 +1,158 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=================================
+Block Device (blkdev) LED Trigger
+=================================
+
+Available when ``CONFIG_LEDS_TRIGGER_BLKDEV=y`` or
+``CONFIG_LEDS_TRIGGER_BLKDEV=m``.
+
+See also:
+
+* ``Documentation/ABI/testing/sysfs-class-led-trigger-blkdev``
+* ``Documentation/ABI/stable/sysfs-block`` (``/sys/block/<disk>/linked_leds``)
+
+Overview
+========
+
+.. note::
+	The examples below use ``<LED>`` to refer to the name of a
+	system-specific LED.  If no suitable LED is available on a test
+	system (in a virtual machine, for example), it is possible to
+	use a userspace LED.  (See ``Documentation/leds/uleds.rst``.)
+
+Verify that the ``blkdev`` LED trigger is available::
+
+	# grep blkdev /sys/class/leds/<LED>/trigger
+	... rfkill-none blkdev
+
+(If the previous command produces no output, you may need to load the trigger
+module - ``modprobe ledtrig_blkdev``.  If the module is not available, check
+the value of ``CONFIG_LEDS_TRIGGER_BLKDEV`` in your kernel configuration.)
+
+Associate the LED with the ``blkdev`` LED trigger::
+
+	# echo blkdev > /sys/class/leds/<LED>/trigger
+
+	# cat /sys/class/leds/<LED>/trigger
+	... rfkill-none [blkdev]
+
+Note that several new device attributes are available in the
+``/sys/class/leds/<LED>`` directory.
+
+* ``link_dev_by_path``, ``unlink_dev_by_path``, and ``unlink_dev_by_name`` are
+  used to manage the set of block devices associated with this LED.  The LED
+  will blink when activity occurs on any of its linked devices.
+
+* ``blink_on_read``, ``blink_on_write``, ``blink_on_discard``, and
+  ``blink_on_flush`` are boolean values that determine whether the LED will
+  blink when a particular type of activity is detected on one of its linked
+  block devices.
+
+* ``blink_time`` is the duration (in milliseconds) of each blink of this LED.
+  (The minimum value is 10 milliseconds.)
+
+* ``check_interval`` is the frequency (in milliseconds) with which block devices
+  linked to this LED will be checked for activity and the LED blinked (if the
+  correct type of activity has occurred).
+
+* The ``linked_devices`` directory will contain a symbolic link to every device
+  that is associated with this LED.
+
+Link a block device to the LED::
+
+	# echo /dev/sda > /sys/class/leds/<LED>/link_dev_by_path
+
+	# ls /sys/class/leds/<LED>/linked_devices
+	sda
+
+(The value written to ``link_dev_by_path`` must be the path of the device
+special file, such as ``/dev/sda``, that represents the block device - or the
+path of a symbolic link to such a device special file.)
+
+Activity on the device will now cause the LED to blink.  The duration of each
+blink (in milliseconds) can be adjusted by setting
+``/sys/class/leds/<LED>/blink_time``.  (But see **check_interval and
+blink_time** below.)
+
+Associate a second device with the LED::
+
+	# echo /dev/sdb > /sys/class/leds/<LED>/link_dev_by_path
+
+	# ls /sys/class/leds/<LED>/linked_devices
+	sda  sdb
+
+When a block device is linked to one or more LEDs, the LEDs are linked from
+the device's ``linked_leds`` directory::
+
+	# ls /sys/class/block/sd{a,b}/linked_leds
+	/sys/class/block/sda/linked_leds:
+	<LED>
+
+	/sys/class/block/sdb/linked_leds:
+	<LED>
+
+(The ``linked_leds`` directory only exists when the block device is linked to
+at least one LED.)
+
+``check_interval`` and ``blink_time``
+=====================================
+
+* By default, linked block devices are checked for activity every 100
+  milliseconds.  This frequency can be changed for an LED via the
+  ``/sys/class/leds/<led>/check_interval`` attribute.  (The minimum value is 25
+  milliseconds.)
+
+* All block devices associated with an LED are checked for activity every
+  ``check_interval`` milliseconds, and a blink is triggered if the correct type
+  of activity (as determined by the LED's ``blink_on_*`` attributes) is
+  detected.  The duration of an LED's blink is determined by its ``blink_time``
+  attribute.  Thus (when the correct type of activity is detected), the LED will
+  be on for ``blink_time`` milliseconds and off for
+  ``check_interval - blink_time`` milliseconds.
+
+* The LED subsystem ignores new blink requests for an LED that is already in
+  in the process of blinking, so setting a ``blink_time`` greater than or equal
+  to ``check_interval`` will cause some blinks to be missed.
+
+* Because of processing times, scheduling latencies, etc., avoiding missed
+  blinks actually requires a difference of at least a few milliseconds between
+  the ``blink_time`` and ``check_interval``.  The required difference is likely
+  to vary from system to system.  As a  reference, a Thecus N5550 NAS requires a
+  difference of 7 milliseconds (e.g. ``check_interval == 100``,
+  ``blink_time == 93``).
+
+* The default values (``check_interval == 100``, ``blink_time == 75``) cause the
+  LED associated with a continuously active device to blink rapidly.  For a more
+  "always on" effect, increase the ``blink_time`` (but not too much; see the
+  previous bullet).
+
+Other Notes
+===========
+
+* Many (possibly all) types of block devices work with this trigger, including:
+
+  * SCSI (including SATA and USB) hard disk drives and SSDs
+  * SCSI (including SATA and USB) optical drives
+  * NVMe SSDs
+  * SD cards
+  * loopback block devices (``/dev/loop*``)
+  * device mapper devices, such as LVM logical volumes
+  * MD RAID devices
+  * zRAM compressed RAM-disks
+  * partitions on block devices that support them
+
+* The names of the symbolic links in ``/sys/class/leds/<LED>/linked_devices``
+  are **kernel** names, which may not match the paths used for
+  ``link_dev_by_path`` and ``unlink_dev_by_path``.  This is most likely when a
+  symbolic link is used to refer to the device (as is common with logical
+  volumes), but it can be true for any device, because nothing prevents the
+  creation of device special files with arbitrary names (e.g.
+  ``sudo mknod /foo b 8 0``).
+
+  Kernel names can be used to unlink block devices from LEDs by writing them to
+  the LED's ``unlink_dev_by_name`` attribute.
+
+* The ``blkdev`` LED trigger supports many-to-many device/LED associations.
+  A device can be associated with multiple LEDs, and an LED can be associated
+  with multiple devices.
-- 
2.41.0.159.g0bfa463d37

From 14dd8bf0b310696a304e43d53f01afc767761170 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 17 May 2023 15:19:31 +0200
Subject: [PATCH 10/17] decompressor: provide missing prototypes

The entry points for the decompressor don't always have a prototype
included in the .c file:

lib/decompress_inflate.c:42:17: error: no previous prototype for '__gunzip' [-Werror=missing-prototypes]
lib/decompress_unxz.c:251:17: error: no previous prototype for 'unxz' [-Werror=missing-prototypes]
lib/decompress_unzstd.c:331:17: error: no previous prototype for 'unzstd' [-Werror=missing-prototypes]

Include the correct headers for unxz and unzstd, and mark the inflate
function above as unconditionally 'static' to avoid these warnings.

Link: https://lkml.kernel.org/r/20230517131936.936840-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 lib/decompress_inflate.c | 2 +-
 lib/decompress_unxz.c    | 2 ++
 lib/decompress_unzstd.c  | 2 ++
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/decompress_inflate.c b/lib/decompress_inflate.c
index 6130c42b8..e19199f4a 100644
--- a/lib/decompress_inflate.c
+++ b/lib/decompress_inflate.c
@@ -39,7 +39,7 @@ static long INIT nofill(void *buffer, unsigned long len)
 }
 
 /* Included from initramfs et al code */
-STATIC int INIT __gunzip(unsigned char *buf, long len,
+static int INIT __gunzip(unsigned char *buf, long len,
 		       long (*fill)(void*, unsigned long),
 		       long (*flush)(void*, unsigned long),
 		       unsigned char *out_buf, long out_len,
diff --git a/lib/decompress_unxz.c b/lib/decompress_unxz.c
index 9f4262ee3..353268b9f 100644
--- a/lib/decompress_unxz.c
+++ b/lib/decompress_unxz.c
@@ -102,6 +102,8 @@
  */
 #ifdef STATIC
 #	define XZ_PREBOOT
+#else
+#include <linux/decompress/unxz.h>
 #endif
 #ifdef __KERNEL__
 #	include <linux/decompress/mm.h>
diff --git a/lib/decompress_unzstd.c b/lib/decompress_unzstd.c
index a512b99ae..bba2c0bb1 100644
--- a/lib/decompress_unzstd.c
+++ b/lib/decompress_unzstd.c
@@ -69,6 +69,8 @@
 # define UNZSTD_PREBOOT
 # include "xxhash.c"
 # include "zstd/decompress_sources.h"
+#else
+#include <linux/decompress/unzstd.h>
 #endif
 
 #include <linux/decompress/mm.h>
-- 
2.41.0.159.g0bfa463d37

From 446eb3e33e73001556214cb8fcf7fefa4406ebe4 Mon Sep 17 00:00:00 2001
From: Noah Goldstein <goldstein.w.n@gmail.com>
Date: Wed, 10 May 2023 20:10:02 -0500
Subject: [PATCH 11/17] x86/csum: Improve performance of `csum_partial`

1) Add special case for len == 40 as that is the hottest value. The
   nets a ~8-9% latency improvement and a ~30% throughput improvement
   in the len == 40 case.

2) Use multiple accumulators in the 64-byte loop. This dramatically
   improves ILP and results in up to a 40% latency/throughput
   improvement (better for more iterations).

Results from benchmarking on Icelake. Times measured with rdtsc()
 len   lat_new   lat_old      r    tput_new  tput_old      r
   8      3.58      3.47  1.032        3.58      3.51  1.021
  16      4.14      4.02  1.028        3.96      3.78  1.046
  24      4.99      5.03  0.992        4.23      4.03  1.050
  32      5.09      5.08  1.001        4.68      4.47  1.048
  40      5.57      6.08  0.916        3.05      4.43  0.690
  48      6.65      6.63  1.003        4.97      4.69  1.059
  56      7.74      7.72  1.003        5.22      4.95  1.055
  64      6.65      7.22  0.921        6.38      6.42  0.994
  96      9.43      9.96  0.946        7.46      7.54  0.990
 128      9.39     12.15  0.773        8.90      8.79  1.012
 200     12.65     18.08  0.699       11.63     11.60  1.002
 272     15.82     23.37  0.677       14.43     14.35  1.005
 440     24.12     36.43  0.662       21.57     22.69  0.951
 952     46.20     74.01  0.624       42.98     53.12  0.809
1024     47.12     78.24  0.602       46.36     58.83  0.788
1552     72.01    117.30  0.614       71.92     96.78  0.743
2048     93.07    153.25  0.607       93.28    137.20  0.680
2600    114.73    194.30  0.590      114.28    179.32  0.637
3608    156.34    268.41  0.582      154.97    254.02  0.610
4096    175.01    304.03  0.576      175.89    292.08  0.602

There is no such thing as a free lunch, however, and the special case
for len == 40 does add overhead to the len != 40 cases. This seems to
amount to be ~5% throughput and slightly less in terms of latency.

Testing:
Part of this change is a new kunit test. The tests check all
alignment X length pairs in [0, 64) X [0, 512).
There are three cases.
    1) Precomputed random inputs/seed. The expected results where
       generated use the generic implementation (which is assumed to be
       non-buggy).
    2) An input of all 1s. The goal of this test is to catch any case
       a carry is missing.
    3) An input that never carries. The goal of this test si to catch
       any case of incorrectly carrying.

More exhaustive tests that test all alignment X length pairs in
[0, 8192) X [0, 8192] on random data are also available here:
https://github.com/goldsteinn/csum-reproduction

The reposity also has the code for reproducing the above benchmark
numbers.

Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230511011002.935690-1-goldstein.w.n%40gmail.com
---
 arch/x86/lib/csum-partial_64.c |  97 ++++++----
 lib/Kconfig.debug              |  17 ++
 lib/Makefile                   |   1 +
 lib/checksum_kunit.c           | 334 +++++++++++++++++++++++++++++++++
 4 files changed, 417 insertions(+), 32 deletions(-)
 create mode 100644 lib/checksum_kunit.c

diff --git a/arch/x86/lib/csum-partial_64.c b/arch/x86/lib/csum-partial_64.c
index 50734a230..fe5861951 100644
--- a/arch/x86/lib/csum-partial_64.c
+++ b/arch/x86/lib/csum-partial_64.c
@@ -5,22 +5,32 @@
  * This file contains network checksum routines that are better done
  * in an architecture-specific manner due to speed.
  */
- 
+
 #include <linux/compiler.h>
 #include <linux/export.h>
 #include <asm/checksum.h>
 #include <asm/word-at-a-time.h>
 
-static inline unsigned short from32to16(unsigned a) 
+static inline unsigned short from32to16(unsigned a)
 {
-	unsigned short b = a >> 16; 
+	unsigned short b = a >> 16;
 	asm("addw %w2,%w0\n\t"
-	    "adcw $0,%w0\n" 
+	    "adcw $0,%w0\n"
 	    : "=r" (b)
 	    : "0" (b), "r" (a));
 	return b;
 }
 
+static inline __wsum csum_tail(unsigned int result, u64 temp64, int odd)
+{
+	result = add32_with_carry(temp64 >> 32, temp64 & 0xffffffff);
+	if (unlikely(odd)) {
+		result = from32to16(result);
+		result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
+	}
+	return (__force __wsum)result;
+}
+
 /*
  * Do a checksum on an arbitrary memory area.
  * Returns a 32bit checksum.
@@ -47,21 +57,52 @@ __wsum csum_partial(const void *buff, int len, __wsum sum)
 		buff++;
 	}
 
-	while (unlikely(len >= 64)) {
+	/*
+	 * len == 40 is the hot case due to IPv6 headers, but annotating it likely()
+	 * has noticeable negative affect on codegen for all other cases with
+	 * minimal performance benefit here.
+	 */
+	if (len == 40) {
 		asm("addq 0*8(%[src]),%[res]\n\t"
 		    "adcq 1*8(%[src]),%[res]\n\t"
 		    "adcq 2*8(%[src]),%[res]\n\t"
 		    "adcq 3*8(%[src]),%[res]\n\t"
 		    "adcq 4*8(%[src]),%[res]\n\t"
-		    "adcq 5*8(%[src]),%[res]\n\t"
-		    "adcq 6*8(%[src]),%[res]\n\t"
-		    "adcq 7*8(%[src]),%[res]\n\t"
 		    "adcq $0,%[res]"
-		    : [res] "+r" (temp64)
-		    : [src] "r" (buff)
-		    : "memory");
-		buff += 64;
-		len -= 64;
+		    : [res] "+r"(temp64)
+		    : [src] "r"(buff), "m"(*(const char(*)[40])buff));
+		return csum_tail(result, temp64, odd);
+	}
+	if (unlikely(len >= 64)) {
+		/*
+		 * Extra accumulators for better ILP in the loop.
+		 */
+		u64 tmp_accum, tmp_carries;
+
+		asm("xorl %k[tmp_accum],%k[tmp_accum]\n\t"
+		    "xorl %k[tmp_carries],%k[tmp_carries]\n\t"
+		    "subl $64, %[len]\n\t"
+		    "1:\n\t"
+		    "addq 0*8(%[src]),%[res]\n\t"
+		    "adcq 1*8(%[src]),%[res]\n\t"
+		    "adcq 2*8(%[src]),%[res]\n\t"
+		    "adcq 3*8(%[src]),%[res]\n\t"
+		    "adcl $0,%k[tmp_carries]\n\t"
+		    "addq 4*8(%[src]),%[tmp_accum]\n\t"
+		    "adcq 5*8(%[src]),%[tmp_accum]\n\t"
+		    "adcq 6*8(%[src]),%[tmp_accum]\n\t"
+		    "adcq 7*8(%[src]),%[tmp_accum]\n\t"
+		    "adcl $0,%k[tmp_carries]\n\t"
+		    "addq $64, %[src]\n\t"
+		    "subl $64, %[len]\n\t"
+		    "jge 1b\n\t"
+		    "addq %[tmp_accum],%[res]\n\t"
+		    "adcq %[tmp_carries],%[res]\n\t"
+		    "adcq $0,%[res]"
+		    : [tmp_accum] "=&r"(tmp_accum),
+		      [tmp_carries] "=&r"(tmp_carries), [res] "+r"(temp64),
+		      [len] "+r"(len), [src] "+r"(buff)
+		    : "m"(*(const char *)buff));
 	}
 
 	if (len & 32) {
@@ -70,45 +111,37 @@ __wsum csum_partial(const void *buff, int len, __wsum sum)
 		    "adcq 2*8(%[src]),%[res]\n\t"
 		    "adcq 3*8(%[src]),%[res]\n\t"
 		    "adcq $0,%[res]"
-			: [res] "+r" (temp64)
-			: [src] "r" (buff)
-			: "memory");
+		    : [res] "+r"(temp64)
+		    : [src] "r"(buff), "m"(*(const char(*)[32])buff));
 		buff += 32;
 	}
 	if (len & 16) {
 		asm("addq 0*8(%[src]),%[res]\n\t"
 		    "adcq 1*8(%[src]),%[res]\n\t"
 		    "adcq $0,%[res]"
-			: [res] "+r" (temp64)
-			: [src] "r" (buff)
-			: "memory");
+		    : [res] "+r"(temp64)
+		    : [src] "r"(buff), "m"(*(const char(*)[16])buff));
 		buff += 16;
 	}
 	if (len & 8) {
 		asm("addq 0*8(%[src]),%[res]\n\t"
 		    "adcq $0,%[res]"
-			: [res] "+r" (temp64)
-			: [src] "r" (buff)
-			: "memory");
+		    : [res] "+r"(temp64)
+		    : [src] "r"(buff), "m"(*(const char(*)[8])buff));
 		buff += 8;
 	}
 	if (len & 7) {
-		unsigned int shift = (8 - (len & 7)) * 8;
+		unsigned int shift = (-len << 3) & 63;
 		unsigned long trail;
 
 		trail = (load_unaligned_zeropad(buff) << shift) >> shift;
 
 		asm("addq %[trail],%[res]\n\t"
 		    "adcq $0,%[res]"
-			: [res] "+r" (temp64)
-			: [trail] "r" (trail));
+		    : [res] "+r"(temp64)
+		    : [trail] "r"(trail));
 	}
-	result = add32_with_carry(temp64 >> 32, temp64 & 0xffffffff);
-	if (unlikely(odd)) {
-		result = from32to16(result);
-		result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
-	}
-	return (__force __wsum)result;
+	return csum_tail(result, temp64, odd);
 }
 EXPORT_SYMBOL(csum_partial);
 
@@ -118,6 +151,6 @@ EXPORT_SYMBOL(csum_partial);
  */
 __sum16 ip_compute_csum(const void *buff, int len)
 {
-	return csum_fold(csum_partial(buff,len,0));
+	return csum_fold(csum_partial(buff, len, 0));
 }
 EXPORT_SYMBOL(ip_compute_csum);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ce51d4dc6..f2d6e9dd8 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2453,6 +2453,23 @@ config BITFIELD_KUNIT
 
 	  If unsure, say N.
 
+config CHECKSUM_KUNIT
+	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Enable this option to test the checksum functions at boot.
+
+	  KUnit tests run during boot and output the results to the debug log
+	  in TAP format (http://testanything.org/). Only useful for kernel devs
+	  running the KUnit test harness, and not intended for inclusion into a
+	  production build.
+
+	  For more information on KUnit and unit tests in general please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.
+
 config HASH_KUNIT_TEST
 	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
 	depends on KUNIT
diff --git a/lib/Makefile b/lib/Makefile
index 876fcdeae..cd37ec1d9 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -377,6 +377,7 @@ obj-$(CONFIG_PLDMFW) += pldmfw/
 # KUnit tests
 CFLAGS_bitfield_kunit.o := $(DISABLE_STRUCTLEAK_PLUGIN)
 obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o
+obj-$(CONFIG_CHECKSUM_KUNIT) += checksum_kunit.o
 obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
 obj-$(CONFIG_HASHTABLE_KUNIT_TEST) += hashtable_test.o
 obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
diff --git a/lib/checksum_kunit.c b/lib/checksum_kunit.c
new file mode 100644
index 000000000..ace3c4799
--- /dev/null
+++ b/lib/checksum_kunit.c
@@ -0,0 +1,334 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Test cases csum_partial and csum_fold
+ */
+
+#include <kunit/test.h>
+#include <asm/checksum.h>
+
+#define MAX_LEN 512
+#define MAX_ALIGN 64
+#define TEST_BUFLEN (MAX_LEN + MAX_ALIGN)
+
+static const __wsum random_init_sum = 0x2847aab;
+static const u8 random_buf[] = {
+	0xac, 0xd7, 0x76, 0x69, 0x6e, 0xf2, 0x93, 0x2c, 0x1f, 0xe0, 0xde, 0x86,
+	0x8f, 0x54, 0x33, 0x90, 0x95, 0xbf, 0xff, 0xb9, 0xea, 0x62, 0x6e, 0xb5,
+	0xd3, 0x4f, 0xf5, 0x60, 0x50, 0x5c, 0xc7, 0xfa, 0x6d, 0x1a, 0xc7, 0xf0,
+	0xd2, 0x2c, 0x12, 0x3d, 0x88, 0xe3, 0x14, 0x21, 0xb1, 0x5e, 0x45, 0x31,
+	0xa2, 0x85, 0x36, 0x76, 0xba, 0xd8, 0xad, 0xbb, 0x9e, 0x49, 0x8f, 0xf7,
+	0xce, 0xea, 0xef, 0xca, 0x2c, 0x29, 0xf7, 0x15, 0x5c, 0x1d, 0x4d, 0x09,
+	0x1f, 0xe2, 0x14, 0x31, 0x8c, 0x07, 0x57, 0x23, 0x1f, 0x6f, 0x03, 0xe1,
+	0x93, 0x19, 0x53, 0x03, 0x45, 0x49, 0x9a, 0x3b, 0x8e, 0x0c, 0x12, 0x5d,
+	0x8a, 0xb8, 0x9b, 0x8c, 0x9a, 0x03, 0xe5, 0xa2, 0x43, 0xd2, 0x3b, 0x4e,
+	0x7e, 0x30, 0x3c, 0x22, 0x2d, 0xc5, 0xfc, 0x9e, 0xdb, 0xc6, 0xf9, 0x69,
+	0x12, 0x39, 0x1f, 0xa0, 0x11, 0x0c, 0x3f, 0xf5, 0x53, 0xc9, 0x30, 0xfb,
+	0xb0, 0xdd, 0x21, 0x1d, 0x34, 0xe2, 0x65, 0x30, 0xf1, 0xe8, 0x1b, 0xe7,
+	0x55, 0x0d, 0xeb, 0xbd, 0xcc, 0x9d, 0x24, 0xa4, 0xad, 0xa7, 0x93, 0x47,
+	0x19, 0x2e, 0xc4, 0x5c, 0x3b, 0xc7, 0x6d, 0x95, 0x0c, 0x47, 0x60, 0xaf,
+	0x5b, 0x47, 0xee, 0xdc, 0x31, 0x31, 0x14, 0x12, 0x7e, 0x9e, 0x45, 0xb1,
+	0xc1, 0x69, 0x4b, 0x84, 0xfc, 0x88, 0xc1, 0x9e, 0x46, 0xb4, 0xc2, 0x25,
+	0xc5, 0x6c, 0x4c, 0x22, 0x58, 0x5c, 0xbe, 0xff, 0xea, 0x88, 0x88, 0x7a,
+	0xcb, 0x1c, 0x5d, 0x63, 0xa1, 0xf2, 0x33, 0x0c, 0xa2, 0x16, 0x0b, 0x6e,
+	0x2b, 0x79, 0x58, 0xf7, 0xac, 0xd3, 0x6a, 0x3f, 0x81, 0x57, 0x48, 0x45,
+	0xe3, 0x7c, 0xdc, 0xd6, 0x34, 0x7e, 0xe6, 0x73, 0xfa, 0xcb, 0x31, 0x18,
+	0xa9, 0x0b, 0xee, 0x6b, 0x99, 0xb9, 0x2d, 0xde, 0x22, 0x0e, 0x71, 0x57,
+	0x0e, 0x9b, 0x11, 0xd1, 0x15, 0x41, 0xd0, 0x6b, 0x50, 0x8a, 0x23, 0x64,
+	0xe3, 0x9c, 0xb3, 0x55, 0x09, 0xe9, 0x32, 0x67, 0xf9, 0xe0, 0x73, 0xf1,
+	0x60, 0x66, 0x0b, 0x88, 0x79, 0x8d, 0x4b, 0x52, 0x83, 0x20, 0x26, 0x78,
+	0x49, 0x27, 0xe7, 0x3e, 0x29, 0xa8, 0x18, 0x82, 0x41, 0xdd, 0x1e, 0xcc,
+	0x3b, 0xc4, 0x65, 0xd1, 0x21, 0x40, 0x72, 0xb2, 0x87, 0x5e, 0x16, 0x10,
+	0x80, 0x3f, 0x4b, 0x58, 0x1c, 0xc2, 0x79, 0x20, 0xf0, 0xe0, 0x80, 0xd3,
+	0x52, 0xa5, 0x19, 0x6e, 0x47, 0x90, 0x08, 0xf5, 0x50, 0xe2, 0xd6, 0xae,
+	0xe9, 0x2e, 0xdc, 0xd5, 0xb4, 0x90, 0x1f, 0x79, 0x49, 0x82, 0x21, 0x84,
+	0xa0, 0xb5, 0x2f, 0xff, 0x30, 0x71, 0xed, 0x80, 0x68, 0xb1, 0x6d, 0xef,
+	0xf6, 0xcf, 0xb8, 0x41, 0x79, 0xf5, 0x01, 0xbc, 0x0c, 0x9b, 0x0e, 0x06,
+	0xf3, 0xb0, 0xbb, 0x97, 0xb8, 0xb1, 0xfd, 0x51, 0x4e, 0xef, 0x0a, 0x3d,
+	0x7a, 0x3d, 0xbd, 0x61, 0x00, 0xa2, 0xb3, 0xf0, 0x1d, 0x77, 0x7b, 0x6c,
+	0x01, 0x61, 0xa5, 0xa3, 0xdb, 0xd5, 0xd5, 0xf4, 0xb5, 0x28, 0x9f, 0x0a,
+	0xa3, 0x82, 0x5f, 0x4b, 0x40, 0x0f, 0x05, 0x0e, 0x78, 0xed, 0xbf, 0x17,
+	0xf6, 0x5a, 0x8a, 0x7d, 0xf9, 0x45, 0xc1, 0xd7, 0x1b, 0x9d, 0x6c, 0x07,
+	0x88, 0xf3, 0xbc, 0xf1, 0xea, 0x28, 0x1f, 0xb8, 0x7a, 0x60, 0x3c, 0xce,
+	0x3e, 0x50, 0xb2, 0x0b, 0xcf, 0xe5, 0x08, 0x1f, 0x48, 0x04, 0xf9, 0x35,
+	0x29, 0x15, 0xbe, 0x82, 0x96, 0xc2, 0x55, 0x04, 0x6c, 0x19, 0x45, 0x29,
+	0x0b, 0xb6, 0x49, 0x12, 0xfb, 0x8d, 0x1b, 0x75, 0x8b, 0xd9, 0x6a, 0x5c,
+	0xbe, 0x46, 0x2b, 0x41, 0xfe, 0x21, 0xad, 0x1f, 0x75, 0xe7, 0x90, 0x3d,
+	0xe1, 0xdf, 0x4b, 0xe1, 0x81, 0xe2, 0x17, 0x02, 0x7b, 0x58, 0x8b, 0x92,
+	0x1a, 0xac, 0x46, 0xdd, 0x2e, 0xce, 0x40, 0x09
+};
+static const __sum16 expected_results[] = {
+	0x82d0, 0x8224, 0xab23, 0xaaad, 0x41ad, 0x413f, 0x4f3e, 0x4eab, 0x22ab,
+	0x228c, 0x428b, 0x41ad, 0xbbac, 0xbb1d, 0x671d, 0x66ea, 0xd6e9, 0xd654,
+	0x1754, 0x1655, 0x5d54, 0x5c6a, 0xfa69, 0xf9fb, 0x44fb, 0x4428, 0xf527,
+	0xf432, 0x9432, 0x93e2, 0x37e2, 0x371b, 0x3d1a, 0x3cad, 0x22ad, 0x21e6,
+	0x31e5, 0x3113, 0x0513, 0x0501, 0xc800, 0xc778, 0xe477, 0xe463, 0xc363,
+	0xc2b2, 0x64b2, 0x646d, 0x336d, 0x32cb, 0xadca, 0xad94, 0x3794, 0x36da,
+	0x5ed9, 0x5e2c, 0xa32b, 0xa28d, 0x598d, 0x58fe, 0x61fd, 0x612f, 0x772e,
+	0x763f, 0xac3e, 0xac12, 0x8312, 0x821b, 0x6d1b, 0x6cbf, 0x4fbf, 0x4f72,
+	0x4672, 0x4653, 0x6452, 0x643e, 0x333e, 0x32b2, 0x2bb2, 0x2b5b, 0x085b,
+	0x083c, 0x993b, 0x9938, 0xb837, 0xb7a4, 0x9ea4, 0x9e51, 0x9b51, 0x9b0c,
+	0x520c, 0x5172, 0x1672, 0x15e4, 0x09e4, 0x09d2, 0xacd1, 0xac47, 0xf446,
+	0xf3ab, 0x67ab, 0x6711, 0x6411, 0x632c, 0xc12b, 0xc0e8, 0xeee7, 0xeeac,
+	0xa0ac, 0xa02e, 0x702e, 0x6ff2, 0x4df2, 0x4dc5, 0x88c4, 0x87c8, 0xe9c7,
+	0xe8ec, 0x22ec, 0x21f3, 0xb8f2, 0xb8e0, 0x7fe0, 0x7fc1, 0xdfc0, 0xdfaf,
+	0xd3af, 0xd370, 0xde6f, 0xde1c, 0x151c, 0x14ec, 0x19eb, 0x193b, 0x3c3a,
+	0x3c19, 0x1f19, 0x1ee5, 0x3ce4, 0x3c7f, 0x0c7f, 0x0b8e, 0x238d, 0x2372,
+	0x3c71, 0x3c1c, 0x2f1c, 0x2e31, 0x7130, 0x7064, 0xd363, 0xd33f, 0x2f3f,
+	0x2e92, 0x8791, 0x86fe, 0x3ffe, 0x3fe5, 0x11e5, 0x1121, 0xb520, 0xb4e5,
+	0xede4, 0xed77, 0x5877, 0x586b, 0x116b, 0x110b, 0x620a, 0x61af, 0x1aaf,
+	0x19c1, 0x3dc0, 0x3d8f, 0x0c8f, 0x0c7b, 0xfa7a, 0xf9fc, 0x5bfc, 0x5bb7,
+	0xaab6, 0xa9f5, 0x40f5, 0x40aa, 0xbca9, 0xbbad, 0x33ad, 0x32ec, 0x94eb,
+	0x94a5, 0xe0a4, 0xdfe2, 0xbae2, 0xba1d, 0x4e1d, 0x4dd1, 0x2bd1, 0x2b79,
+	0xcf78, 0xceba, 0xcfb9, 0xcecf, 0x46cf, 0x4647, 0xcc46, 0xcb7b, 0xaf7b,
+	0xaf1e, 0x4c1e, 0x4b7d, 0x597c, 0x5949, 0x4d49, 0x4ca7, 0x36a7, 0x369c,
+	0xc89b, 0xc870, 0x4f70, 0x4f18, 0x5817, 0x576b, 0x846a, 0x8400, 0x4500,
+	0x447f, 0xed7e, 0xed36, 0xa836, 0xa753, 0x2b53, 0x2a77, 0x5476, 0x5442,
+	0xd641, 0xd55b, 0x625b, 0x6161, 0x9660, 0x962f, 0x7e2f, 0x7d86, 0x7286,
+	0x7198, 0x0698, 0x05ff, 0x4cfe, 0x4cd1, 0x6ed0, 0x6eae, 0x60ae, 0x603d,
+	0x093d, 0x092f, 0x6e2e, 0x6e1d, 0x9d1c, 0x9d07, 0x5c07, 0x5b37, 0xf036,
+	0xefe6, 0x65e6, 0x65c3, 0x01c3, 0x00e0, 0x64df, 0x642c, 0x0f2c, 0x0f23,
+	0x2622, 0x25f0, 0xbeef, 0xbdf6, 0xddf5, 0xdd82, 0xec81, 0xec21, 0x8621,
+	0x8616, 0xfe15, 0xfd9c, 0x709c, 0x7051, 0x1e51, 0x1dce, 0xfdcd, 0xfda7,
+	0x85a7, 0x855e, 0x5e5e, 0x5d77, 0x1f77, 0x1f4e, 0x774d, 0x7735, 0xf534,
+	0xf4f3, 0x17f3, 0x17d5, 0x4bd4, 0x4b99, 0x8798, 0x8733, 0xb632, 0xb611,
+	0x7611, 0x759f, 0xc39e, 0xc317, 0x6517, 0x6501, 0x5501, 0x5481, 0x1581,
+	0x1536, 0xbd35, 0xbd19, 0xfb18, 0xfa9f, 0xda9f, 0xd9af, 0xf9ae, 0xf92e,
+	0x262e, 0x25dc, 0x80db, 0x80c2, 0x12c2, 0x127b, 0x827a, 0x8272, 0x8d71,
+	0x8d21, 0xab20, 0xaa4a, 0xfc49, 0xfb60, 0xcd60, 0xcc84, 0xf783, 0xf6cf,
+	0x66cf, 0x66b0, 0xedaf, 0xed66, 0x6b66, 0x6b45, 0xe744, 0xe6a4, 0x31a4,
+	0x3175, 0x3274, 0x3244, 0xc143, 0xc056, 0x4056, 0x3fee, 0x8eed, 0x8e80,
+	0x9f7f, 0x9e89, 0xcf88, 0xced0, 0x8dd0, 0x8d57, 0x9856, 0x9855, 0xdc54,
+	0xdc48, 0x4148, 0x413a, 0x3b3a, 0x3a47, 0x8a46, 0x898b, 0xf28a, 0xf1d2,
+	0x40d2, 0x3fd5, 0xeed4, 0xee86, 0xff85, 0xff7b, 0xc27b, 0xc201, 0x8501,
+	0x8444, 0x2344, 0x2344, 0x8143, 0x8090, 0x908f, 0x9072, 0x1972, 0x18f7,
+	0xacf6, 0xacf5, 0x4bf5, 0x4b50, 0xa84f, 0xa774, 0xd273, 0xd19e, 0xdd9d,
+	0xdce8, 0xb4e8, 0xb449, 0xaa49, 0xa9a6, 0x27a6, 0x2747, 0xdc46, 0xdc06,
+	0xcd06, 0xcd01, 0xbf01, 0xbe89, 0xd188, 0xd0c9, 0xb9c9, 0xb8d3, 0x5ed3,
+	0x5e49, 0xe148, 0xe04f, 0x9b4f, 0x9a8e, 0xc38d, 0xc372, 0x2672, 0x2606,
+	0x1f06, 0x1e7e, 0x2b7d, 0x2ac1, 0x39c0, 0x38d6, 0x10d6, 0x10b7, 0x58b6,
+	0x583c, 0xf83b, 0xf7ff, 0x29ff, 0x29c1, 0xd9c0, 0xd90e, 0xce0e, 0xcd3f,
+	0xe83e, 0xe836, 0xc936, 0xc8ee, 0xc4ee, 0xc3f5, 0x8ef5, 0x8ecc, 0x79cc,
+	0x790e, 0xf70d, 0xf677, 0x3477, 0x3422, 0x3022, 0x2fb6, 0x16b6, 0x1671,
+	0xed70, 0xed65, 0x3765, 0x371c, 0x251c, 0x2421, 0x9720, 0x9705, 0x2205,
+	0x217a, 0x4879, 0x480f, 0xec0e, 0xeb50, 0xa550, 0xa525, 0x6425, 0x6327,
+	0x4227, 0x417a, 0x227a, 0x2205, 0x3b04, 0x3a74, 0xfd73, 0xfc92, 0x1d92,
+	0x1d47, 0x3c46, 0x3bc5, 0x59c4, 0x59ad, 0x57ad, 0x5732, 0xff31, 0xfea6,
+	0x6ca6, 0x6c8c, 0xc08b, 0xc045, 0xe344, 0xe316, 0x1516, 0x14d6,
+};
+static const __wsum init_sums_no_overflow[] = {
+	0xffffffff, 0xfffffffb, 0xfffffbfb, 0xfffffbf7, 0xfffff7f7, 0xfffff7f3,
+	0xfffff3f3, 0xfffff3ef, 0xffffefef, 0xffffefeb, 0xffffebeb, 0xffffebe7,
+	0xffffe7e7, 0xffffe7e3, 0xffffe3e3, 0xffffe3df, 0xffffdfdf, 0xffffdfdb,
+	0xffffdbdb, 0xffffdbd7, 0xffffd7d7, 0xffffd7d3, 0xffffd3d3, 0xffffd3cf,
+	0xffffcfcf, 0xffffcfcb, 0xffffcbcb, 0xffffcbc7, 0xffffc7c7, 0xffffc7c3,
+	0xffffc3c3, 0xffffc3bf, 0xffffbfbf, 0xffffbfbb, 0xffffbbbb, 0xffffbbb7,
+	0xffffb7b7, 0xffffb7b3, 0xffffb3b3, 0xffffb3af, 0xffffafaf, 0xffffafab,
+	0xffffabab, 0xffffaba7, 0xffffa7a7, 0xffffa7a3, 0xffffa3a3, 0xffffa39f,
+	0xffff9f9f, 0xffff9f9b, 0xffff9b9b, 0xffff9b97, 0xffff9797, 0xffff9793,
+	0xffff9393, 0xffff938f, 0xffff8f8f, 0xffff8f8b, 0xffff8b8b, 0xffff8b87,
+	0xffff8787, 0xffff8783, 0xffff8383, 0xffff837f, 0xffff7f7f, 0xffff7f7b,
+	0xffff7b7b, 0xffff7b77, 0xffff7777, 0xffff7773, 0xffff7373, 0xffff736f,
+	0xffff6f6f, 0xffff6f6b, 0xffff6b6b, 0xffff6b67, 0xffff6767, 0xffff6763,
+	0xffff6363, 0xffff635f, 0xffff5f5f, 0xffff5f5b, 0xffff5b5b, 0xffff5b57,
+	0xffff5757, 0xffff5753, 0xffff5353, 0xffff534f, 0xffff4f4f, 0xffff4f4b,
+	0xffff4b4b, 0xffff4b47, 0xffff4747, 0xffff4743, 0xffff4343, 0xffff433f,
+	0xffff3f3f, 0xffff3f3b, 0xffff3b3b, 0xffff3b37, 0xffff3737, 0xffff3733,
+	0xffff3333, 0xffff332f, 0xffff2f2f, 0xffff2f2b, 0xffff2b2b, 0xffff2b27,
+	0xffff2727, 0xffff2723, 0xffff2323, 0xffff231f, 0xffff1f1f, 0xffff1f1b,
+	0xffff1b1b, 0xffff1b17, 0xffff1717, 0xffff1713, 0xffff1313, 0xffff130f,
+	0xffff0f0f, 0xffff0f0b, 0xffff0b0b, 0xffff0b07, 0xffff0707, 0xffff0703,
+	0xffff0303, 0xffff02ff, 0xfffffefe, 0xfffffefa, 0xfffffafa, 0xfffffaf6,
+	0xfffff6f6, 0xfffff6f2, 0xfffff2f2, 0xfffff2ee, 0xffffeeee, 0xffffeeea,
+	0xffffeaea, 0xffffeae6, 0xffffe6e6, 0xffffe6e2, 0xffffe2e2, 0xffffe2de,
+	0xffffdede, 0xffffdeda, 0xffffdada, 0xffffdad6, 0xffffd6d6, 0xffffd6d2,
+	0xffffd2d2, 0xffffd2ce, 0xffffcece, 0xffffceca, 0xffffcaca, 0xffffcac6,
+	0xffffc6c6, 0xffffc6c2, 0xffffc2c2, 0xffffc2be, 0xffffbebe, 0xffffbeba,
+	0xffffbaba, 0xffffbab6, 0xffffb6b6, 0xffffb6b2, 0xffffb2b2, 0xffffb2ae,
+	0xffffaeae, 0xffffaeaa, 0xffffaaaa, 0xffffaaa6, 0xffffa6a6, 0xffffa6a2,
+	0xffffa2a2, 0xffffa29e, 0xffff9e9e, 0xffff9e9a, 0xffff9a9a, 0xffff9a96,
+	0xffff9696, 0xffff9692, 0xffff9292, 0xffff928e, 0xffff8e8e, 0xffff8e8a,
+	0xffff8a8a, 0xffff8a86, 0xffff8686, 0xffff8682, 0xffff8282, 0xffff827e,
+	0xffff7e7e, 0xffff7e7a, 0xffff7a7a, 0xffff7a76, 0xffff7676, 0xffff7672,
+	0xffff7272, 0xffff726e, 0xffff6e6e, 0xffff6e6a, 0xffff6a6a, 0xffff6a66,
+	0xffff6666, 0xffff6662, 0xffff6262, 0xffff625e, 0xffff5e5e, 0xffff5e5a,
+	0xffff5a5a, 0xffff5a56, 0xffff5656, 0xffff5652, 0xffff5252, 0xffff524e,
+	0xffff4e4e, 0xffff4e4a, 0xffff4a4a, 0xffff4a46, 0xffff4646, 0xffff4642,
+	0xffff4242, 0xffff423e, 0xffff3e3e, 0xffff3e3a, 0xffff3a3a, 0xffff3a36,
+	0xffff3636, 0xffff3632, 0xffff3232, 0xffff322e, 0xffff2e2e, 0xffff2e2a,
+	0xffff2a2a, 0xffff2a26, 0xffff2626, 0xffff2622, 0xffff2222, 0xffff221e,
+	0xffff1e1e, 0xffff1e1a, 0xffff1a1a, 0xffff1a16, 0xffff1616, 0xffff1612,
+	0xffff1212, 0xffff120e, 0xffff0e0e, 0xffff0e0a, 0xffff0a0a, 0xffff0a06,
+	0xffff0606, 0xffff0602, 0xffff0202, 0xffff01fe, 0xfffffdfd, 0xfffffdf9,
+	0xfffff9f9, 0xfffff9f5, 0xfffff5f5, 0xfffff5f1, 0xfffff1f1, 0xfffff1ed,
+	0xffffeded, 0xffffede9, 0xffffe9e9, 0xffffe9e5, 0xffffe5e5, 0xffffe5e1,
+	0xffffe1e1, 0xffffe1dd, 0xffffdddd, 0xffffddd9, 0xffffd9d9, 0xffffd9d5,
+	0xffffd5d5, 0xffffd5d1, 0xffffd1d1, 0xffffd1cd, 0xffffcdcd, 0xffffcdc9,
+	0xffffc9c9, 0xffffc9c5, 0xffffc5c5, 0xffffc5c1, 0xffffc1c1, 0xffffc1bd,
+	0xffffbdbd, 0xffffbdb9, 0xffffb9b9, 0xffffb9b5, 0xffffb5b5, 0xffffb5b1,
+	0xffffb1b1, 0xffffb1ad, 0xffffadad, 0xffffada9, 0xffffa9a9, 0xffffa9a5,
+	0xffffa5a5, 0xffffa5a1, 0xffffa1a1, 0xffffa19d, 0xffff9d9d, 0xffff9d99,
+	0xffff9999, 0xffff9995, 0xffff9595, 0xffff9591, 0xffff9191, 0xffff918d,
+	0xffff8d8d, 0xffff8d89, 0xffff8989, 0xffff8985, 0xffff8585, 0xffff8581,
+	0xffff8181, 0xffff817d, 0xffff7d7d, 0xffff7d79, 0xffff7979, 0xffff7975,
+	0xffff7575, 0xffff7571, 0xffff7171, 0xffff716d, 0xffff6d6d, 0xffff6d69,
+	0xffff6969, 0xffff6965, 0xffff6565, 0xffff6561, 0xffff6161, 0xffff615d,
+	0xffff5d5d, 0xffff5d59, 0xffff5959, 0xffff5955, 0xffff5555, 0xffff5551,
+	0xffff5151, 0xffff514d, 0xffff4d4d, 0xffff4d49, 0xffff4949, 0xffff4945,
+	0xffff4545, 0xffff4541, 0xffff4141, 0xffff413d, 0xffff3d3d, 0xffff3d39,
+	0xffff3939, 0xffff3935, 0xffff3535, 0xffff3531, 0xffff3131, 0xffff312d,
+	0xffff2d2d, 0xffff2d29, 0xffff2929, 0xffff2925, 0xffff2525, 0xffff2521,
+	0xffff2121, 0xffff211d, 0xffff1d1d, 0xffff1d19, 0xffff1919, 0xffff1915,
+	0xffff1515, 0xffff1511, 0xffff1111, 0xffff110d, 0xffff0d0d, 0xffff0d09,
+	0xffff0909, 0xffff0905, 0xffff0505, 0xffff0501, 0xffff0101, 0xffff00fd,
+	0xfffffcfc, 0xfffffcf8, 0xfffff8f8, 0xfffff8f4, 0xfffff4f4, 0xfffff4f0,
+	0xfffff0f0, 0xfffff0ec, 0xffffecec, 0xffffece8, 0xffffe8e8, 0xffffe8e4,
+	0xffffe4e4, 0xffffe4e0, 0xffffe0e0, 0xffffe0dc, 0xffffdcdc, 0xffffdcd8,
+	0xffffd8d8, 0xffffd8d4, 0xffffd4d4, 0xffffd4d0, 0xffffd0d0, 0xffffd0cc,
+	0xffffcccc, 0xffffccc8, 0xffffc8c8, 0xffffc8c4, 0xffffc4c4, 0xffffc4c0,
+	0xffffc0c0, 0xffffc0bc, 0xffffbcbc, 0xffffbcb8, 0xffffb8b8, 0xffffb8b4,
+	0xffffb4b4, 0xffffb4b0, 0xffffb0b0, 0xffffb0ac, 0xffffacac, 0xffffaca8,
+	0xffffa8a8, 0xffffa8a4, 0xffffa4a4, 0xffffa4a0, 0xffffa0a0, 0xffffa09c,
+	0xffff9c9c, 0xffff9c98, 0xffff9898, 0xffff9894, 0xffff9494, 0xffff9490,
+	0xffff9090, 0xffff908c, 0xffff8c8c, 0xffff8c88, 0xffff8888, 0xffff8884,
+	0xffff8484, 0xffff8480, 0xffff8080, 0xffff807c, 0xffff7c7c, 0xffff7c78,
+	0xffff7878, 0xffff7874, 0xffff7474, 0xffff7470, 0xffff7070, 0xffff706c,
+	0xffff6c6c, 0xffff6c68, 0xffff6868, 0xffff6864, 0xffff6464, 0xffff6460,
+	0xffff6060, 0xffff605c, 0xffff5c5c, 0xffff5c58, 0xffff5858, 0xffff5854,
+	0xffff5454, 0xffff5450, 0xffff5050, 0xffff504c, 0xffff4c4c, 0xffff4c48,
+	0xffff4848, 0xffff4844, 0xffff4444, 0xffff4440, 0xffff4040, 0xffff403c,
+	0xffff3c3c, 0xffff3c38, 0xffff3838, 0xffff3834, 0xffff3434, 0xffff3430,
+	0xffff3030, 0xffff302c, 0xffff2c2c, 0xffff2c28, 0xffff2828, 0xffff2824,
+	0xffff2424, 0xffff2420, 0xffff2020, 0xffff201c, 0xffff1c1c, 0xffff1c18,
+	0xffff1818, 0xffff1814, 0xffff1414, 0xffff1410, 0xffff1010, 0xffff100c,
+	0xffff0c0c, 0xffff0c08, 0xffff0808, 0xffff0804, 0xffff0404, 0xffff0400,
+	0xffff0000, 0xfffffffb,
+};
+
+static u8 tmp_buf[TEST_BUFLEN];
+
+#define full_csum(buff, len, sum) csum_fold(csum_partial(buff, len, sum))
+
+#define CHECK_EQ(lhs, rhs) KUNIT_ASSERT_EQ(test, lhs, rhs)
+
+static void assert_setup_correct(struct kunit *test)
+{
+	CHECK_EQ(sizeof(random_buf) / sizeof(random_buf[0]), MAX_LEN);
+	CHECK_EQ(sizeof(expected_results) / sizeof(expected_results[0]),
+		 MAX_LEN);
+	CHECK_EQ(sizeof(init_sums_no_overflow) /
+			 sizeof(init_sums_no_overflow[0]),
+		 MAX_LEN);
+}
+
+/*
+ * Test with randomized input (pre determined random with known results).
+ */
+static void test_csum_fixed_random_inputs(struct kunit *test)
+{
+	int len, align;
+	__wsum result, expec, sum;
+
+	assert_setup_correct(test);
+	for (align = 0; align < TEST_BUFLEN; ++align) {
+		memcpy(&tmp_buf[align], random_buf,
+		       min(MAX_LEN, TEST_BUFLEN - align));
+		for (len = 0; len < MAX_LEN && (align + len) < TEST_BUFLEN;
+		     ++len) {
+			/*
+			 * Test the precomputed random input.
+			 */
+			sum = random_init_sum;
+			result = full_csum(&tmp_buf[align], len, sum);
+			expec = expected_results[len];
+			CHECK_EQ(result, expec);
+		}
+	}
+}
+
+/*
+ * All ones input test. If there are any missing carry operations, it fails.
+ */
+static void test_csum_all_carry_inputs(struct kunit *test)
+{
+	int len, align;
+	__wsum result, expec, sum;
+
+	assert_setup_correct(test);
+	memset(tmp_buf, 0xff, TEST_BUFLEN);
+	for (align = 0; align < TEST_BUFLEN; ++align) {
+		for (len = 0; len < MAX_LEN && (align + len) < TEST_BUFLEN;
+		     ++len) {
+			/*
+			 * All carries from input and initial sum.
+			 */
+			sum = 0xffffffff;
+			result = full_csum(&tmp_buf[align], len, sum);
+			expec = (len & 1) ? 0xff00 : 0;
+			CHECK_EQ(result, expec);
+
+			/*
+			 * All carries from input.
+			 */
+			sum = 0;
+			result = full_csum(&tmp_buf[align], len, sum);
+			if (len & 1)
+				expec = 0xff00;
+			else if (len)
+				expec = 0;
+			else
+				expec = 0xffff;
+			CHECK_EQ(result, expec);
+		}
+	}
+}
+
+/*
+ * Test with input that alone doesn't cause any carries. By selecting the
+ * maximum initial sum, this allows us to test that there are no carries
+ * where there shouldn't be.
+ */
+static void test_csum_no_carry_inputs(struct kunit *test)
+{
+	int len, align;
+	__wsum result, expec, sum;
+
+	assert_setup_correct(test);
+	memset(tmp_buf, 0x4, TEST_BUFLEN);
+	for (align = 0; align < TEST_BUFLEN; ++align) {
+		for (len = 0; len < MAX_LEN && (align + len) < TEST_BUFLEN;
+		     ++len) {
+			/*
+			 * Expect no carries.
+			 */
+			sum = init_sums_no_overflow[len];
+			result = full_csum(&tmp_buf[align], len, sum);
+			expec = 0;
+			CHECK_EQ(result, expec);
+
+			/*
+			 * Expect one carry.
+			 */
+			sum = init_sums_no_overflow[len] + 1;
+			result = full_csum(&tmp_buf[align], len, sum);
+			expec = len ? 0xfffe : 0xffff;
+			CHECK_EQ(result, expec);
+		}
+	}
+}
+
+static struct kunit_case __refdata checksum_test_cases[] = {
+	KUNIT_CASE(test_csum_fixed_random_inputs),
+	KUNIT_CASE(test_csum_all_carry_inputs),
+	KUNIT_CASE(test_csum_no_carry_inputs),
+	{}
+};
+
+static struct kunit_suite checksum_test_suite = {
+	.name = "checksum",
+	.test_cases = checksum_test_cases,
+};
+
+kunit_test_suites(&checksum_test_suite);
+
+MODULE_AUTHOR("Noah Goldstein <goldstein.w.n@gmail.com>");
+MODULE_LICENSE("GPL");
-- 
2.41.0.159.g0bfa463d37

From e79af2ddbfe5df55ddca5f1fa1199b91a1c783cb Mon Sep 17 00:00:00 2001
From: Khalid Aziz <khalid.aziz@oracle.com>
Date: Thu, 25 May 2023 13:15:07 -0600
Subject: [PATCH 12/17] mm, compaction: skip all non-migratable pages during
 scan

Pages pinned in memory through extra refcounts can not be migrated.
Currently as isolate_migratepages_block() scans pages for compaction, it
skips any pinned anonymous pages.  All non-migratable pages should be
skipped and not just the anonymous pinned pages.  This patch adds a check
for extra refcounts on a page to determine if the page can be migrated.
This was seen as a real issue on a customer workload where a large number
of pages were pinned by vfio on the host and any attempts to allocate
hugepages resulted in significant amount of cpu time spent in either
direct compaction or in kcompactd scanning vfio pinned pages over and over
again that can not be migrated.  These are the changes in relevant stats
with this patch for a test run of this scenario:

Before			After
compact_migrate_scanned		329,798,858		370,984,387
compact_free_scanned		40,478,406		25,843,262
compact_isolated		135,470,452		777,235
pgmigrate_success		544,255			507,325
pgmigrate_fail			134,616,282		47
kcompactd CPU time		5:12.81			0:12.28

Before the patch, large number of pages were isolated but most of
them failed to migrate.

Link: https://lkml.kernel.org/r/20230525191507.160076-1-khalid.aziz@oracle.com
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Suggested-by: Steve Sistare <steven.sistare@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 include/linux/migrate.h | 16 +++++++++++++++
 mm/compaction.c         | 44 +++++++++++++++++++++++++++++++++++++----
 mm/migrate.c            | 14 -------------
 3 files changed, 56 insertions(+), 18 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 6241a1596..4f59e15ea 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -141,6 +141,22 @@ const struct movable_operations *page_movable_ops(struct page *page)
 		((unsigned long)page->mapping - PAGE_MAPPING_MOVABLE);
 }
 
+static inline
+int folio_expected_refs(struct address_space *mapping,
+		struct folio *folio)
+{
+	int refs = 1;
+
+	if (!mapping)
+		return refs;
+
+	refs += folio_nr_pages(folio);
+	if (folio_test_private(folio))
+		refs++;
+
+	return refs;
+}
+
 #ifdef CONFIG_NUMA_BALANCING
 int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
 			   int node);
diff --git a/mm/compaction.c b/mm/compaction.c
index c8bcdea15..d3c06bfcb 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -765,6 +765,42 @@ static bool too_many_isolated(pg_data_t *pgdat)
 	return too_many;
 }
 
+/*
+ * Check if this base page should be skipped from isolation because
+ * it has extra refcounts that will prevent it from being migrated.
+ * This code is inspired by similar code in migrate_vma_check_page(),
+ * can_split_folio() and folio_migrate_mapping()
+ */
+static inline bool page_has_extra_refs(struct page *page,
+					struct address_space *mapping)
+{
+	unsigned long extra_refs;
+	struct folio *folio;
+
+	/*
+	 * Skip this check for pages in ZONE_MOVABLE or MIGRATE_CMA
+	 * pages that can not be long term pinned
+	 */
+	if (is_zone_movable_page(page) || is_migrate_cma_page(page))
+		return false;
+
+	folio = page_folio(page);
+
+	/*
+	 * caller holds a ref already from get_page_unless_zero()
+	 * which is accounted for in folio_expected_refs()
+	 */
+	extra_refs = folio_expected_refs(mapping, folio);
+
+	/*
+	 * This is an admittedly racy check but good enough to determine
+	 * if a page is pinned and can not be migrated
+	 */
+	if ((folio_ref_count(folio) - extra_refs) > folio_mapcount(folio))
+		return true;
+	return false;
+}
+
 /**
  * isolate_migratepages_block() - isolate all migrate-able pages within
  *				  a single pageblock
@@ -1003,12 +1039,12 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 			goto isolate_fail;
 
 		/*
-		 * Migration will fail if an anonymous page is pinned in memory,
-		 * so avoid taking lru_lock and isolating it unnecessarily in an
-		 * admittedly racy check.
+		 * Migration will fail if a page has extra refcounts
+		 * from long term pinning preventing it from migrating,
+		 * so avoid taking lru_lock and isolating it unnecessarily.
 		 */
 		mapping = page_mapping(page);
-		if (!mapping && (page_count(page) - 1) > total_mapcount(page))
+		if (!cc->alloc_contig && page_has_extra_refs(page, mapping))
 			goto isolate_fail_put;
 
 		/*
diff --git a/mm/migrate.c b/mm/migrate.c
index 01cac26a3..2b215d9be 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -379,20 +379,6 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd)
 }
 #endif
 
-static int folio_expected_refs(struct address_space *mapping,
-		struct folio *folio)
-{
-	int refs = 1;
-	if (!mapping)
-		return refs;
-
-	refs += folio_nr_pages(folio);
-	if (folio_test_private(folio))
-		refs++;
-
-	return refs;
-}
-
 /*
  * Replace the page in the mapping.
  *
-- 
2.41.0.159.g0bfa463d37

From b4e701b6469f033057bcff93f4cf4c3228043304 Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 15 May 2023 10:35:36 -0400
Subject: [PATCH 13/17] mm: Move mm_count into its own cache line

The mm_struct mm_count field is frequently updated by mmgrab/mmdrop
performed by context switch. This causes false-sharing for surrounding
mm_struct fields which are read-mostly.

This has been observed on a 2sockets/112core/224cpu Intel Sapphire
Rapids server running hackbench, and by the kernel test robot
will-it-scale testcase.

Move the mm_count field into its own cache line to prevent false-sharing
with other mm_struct fields.

Move mm_count to the first field of mm_struct to minimize the amount of
padding required: rather than adding padding before and after the
mm_count field, padding is only added after mm_count.

Note that I noticed this odd comment in mm_struct:

commit 2e3025434a6b ("mm: relocate 'write_protect_seq' in struct mm_struct")

/*
                 * With some kernel config, the current mmap_lock's offset
                 * inside 'mm_struct' is at 0x120, which is very optimal, as
                 * its two hot fields 'count' and 'owner' sit in 2 different
                 * cachelines,  and when mmap_lock is highly contended, both
                 * of the 2 fields will be accessed frequently, current layout
                 * will help to reduce cache bouncing.
                 *
                 * So please be careful with adding new fields before
                 * mmap_lock, which can easily push the 2 fields into one
                 * cacheline.
                 */
                struct rw_semaphore mmap_lock;

This comment is rather odd for a few reasons:

- It requires addition/removal of mm_struct fields to carefully consider
  field alignment of _other_ fields,
- It expresses the wish to keep an "optimal" alignment for a specific
  kernel config.

I suspect that the author of this comment may want to revisit this topic
and perhaps introduce a split-struct approach for struct rw_semaphore,
if the need is to place various fields of this structure in different
cache lines.

Fixes: 223baf9d17f2 ("sched: Fix performance regression introduced by mm_cid")
Fixes: af7f588d8f73 ("sched: Introduce per-memory-map concurrency ID")
Link: https://lore.kernel.org/lkml/7a0c1db1-103d-d518-ed96-1584a28fbf32@efficios.com
Reported-by: kernel test robot <yujie.liu@intel.com>
Link: https://lore.kernel.org/oe-lkp/202305151017.27581d75-yujie.liu@intel.com
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Olivier Dion <odion@efficios.com>
Cc: michael.christie@oracle.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Feng Tang <feng.tang@intel.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: linux-mm@kvack.org
---
 include/linux/mm_types.h | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 306a3d1a0..de10fc797 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -583,6 +583,21 @@ struct mm_cid {
 struct kioctx_table;
 struct mm_struct {
 	struct {
+		/*
+		 * Fields which are often written to are placed in a separate
+		 * cache line.
+		 */
+		struct {
+			/**
+			 * @mm_count: The number of references to &struct
+			 * mm_struct (@mm_users count as 1).
+			 *
+			 * Use mmgrab()/mmdrop() to modify. When this drops to
+			 * 0, the &struct mm_struct is freed.
+			 */
+			atomic_t mm_count;
+		} ____cacheline_aligned_in_smp;
+
 		struct maple_tree mm_mt;
 #ifdef CONFIG_MMU
 		unsigned long (*get_unmapped_area) (struct file *filp,
@@ -620,14 +635,6 @@ struct mm_struct {
 		 */
 		atomic_t mm_users;
 
-		/**
-		 * @mm_count: The number of references to &struct mm_struct
-		 * (@mm_users count as 1).
-		 *
-		 * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
-		 * &struct mm_struct is freed.
-		 */
-		atomic_t mm_count;
 #ifdef CONFIG_SCHED_MM_CID
 		/**
 		 * @pcpu_cid: Per-cpu current cid.
-- 
2.41.0.159.g0bfa463d37

From e7f38950bfc77074c896c77869292f32959a2acf Mon Sep 17 00:00:00 2001
From: Tero Kristo <tero.kristo@linux.intel.com>
Date: Wed, 21 Jun 2023 09:58:39 +0300
Subject: [PATCH 14/17] cpufreq: intel_pstate: Fix
 energy_performance_preference for passive

If the intel_pstate driver is set to passive mode, then writing the
same value to the energy_performance_preference sysfs twice will fail.
This is caused by the wrong return value used (index of the matched
energy_perf_string), instead of the length of the passed in parameter.
Fix by forcing the internal return value to zero when the same
preference is passed in by user. This same issue is not present when
active mode is used for the driver.

Fixes: f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled")
Reported-by: Niklas Neronin <niklas.neronin@intel.com>
Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
---
 drivers/cpufreq/intel_pstate.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 2548ec92f..f29182512 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -824,6 +824,8 @@ static ssize_t store_energy_performance_preference(
 			err = cpufreq_start_governor(policy);
 			if (!ret)
 				ret = err;
+		} else {
+			ret = 0;
 		}
 	}
 
-- 
2.41.0.159.g0bfa463d37

From 1d42548e55797eddc57ede3a4e8c3141ba789e4c Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@alien8.de>
Date: Thu, 22 Jun 2023 11:52:12 +0200
Subject: [PATCH 15/17] x86/barrier: Do not serialize MSR accesses on AMD

AMD does not have the requirement for a synchronization barrier when
acccessing a certain group of MSRs. Do not incur that unnecessary
penalty there.

While at it, move to processor.h to avoid include hell. Untangling that
file properly is a matter for another day.

Some notes on the performance aspect of why this is relevant, courtesy
of Kishon VijayAbraham <Kishon.VijayAbraham@amd.com>:

On a AMD Zen4 system with 96 cores, a modified ipi-bench[1] on a VM
shows x2AVIC IPI rate is 3% to 4% lower than AVIC IPI rate. The
ipi-bench is modified so that the IPIs are sent between two vCPUs in the
same CCX. This also requires to pin the vCPU to a physical core to
prevent any latencies. This simulates the use case of pinning vCPUs to
the thread of a single CCX to avoid interrupt IPI latency.

In order to avoid run-to-run variance (for both x2AVIC and AVIC), the
below configurations are done:

1) Disable Power States in BIOS (to prevent the system from going to
     lower power state)

2) Run the system at fixed frequency 2500MHz (to prevent the system
     from increasing the frequency when the load is more)

With the above configuration:

*) Performance measured using ipi-bench for AVIC:
  Average Latency:  1124.98ns [Time to send IPI from one vCPU to another vCPU]

Cumulative throughput: 42.6759M/s [Total number of IPIs sent in a second from
  				     48 vCPUs simultaneously]

*) Performance measured using ipi-bench for x2AVIC:
  Average Latency:  1172.42ns [Time to send IPI from one vCPU to another vCPU]

Cumulative throughput: 40.9432M/s [Total number of IPIs sent in a second from
  				     48 vCPUs simultaneously]

From above, x2AVIC latency is ~4% more than AVIC. However, the expectation is
x2AVIC performance to be better or equivalent to AVIC. Upon analyzing
the perf captures, it is observed significant time is spent in
weak_wrmsr_fence() invoked by x2apic_send_IPI().

With the fix to skip weak_wrmsr_fence()

*) Performance measured using ipi-bench for x2AVIC:
  Average Latency:  1117.44ns [Time to send IPI from one vCPU to another vCPU]

Cumulative throughput: 42.9608M/s [Total number of IPIs sent in a second from
  				     48 vCPUs simultaneously]

Comparing the performance of x2AVIC with and without the fix, it can be seen
the performance improves by ~4%.

Performance captured using an unmodified ipi-bench using the 'mesh-ipi' option
with and without weak_wrmsr_fence() on a Zen4 system also showed significant
performance improvement without weak_wrmsr_fence(). The 'mesh-ipi' option ignores
CCX or CCD and just picks random vCPU.

Average throughput (10 iterations) with weak_wrmsr_fence(),
        Cumulative throughput: 4933374 IPI/s

Average throughput (10 iterations) without weak_wrmsr_fence(),
        Cumulative throughput: 6355156 IPI/s

[1] https://github.com/bytedance/kvm-utils/tree/master/microbenchmark/ipi-bench

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
 arch/x86/include/asm/barrier.h   | 18 ------------------
 arch/x86/include/asm/processor.h | 19 +++++++++++++++++++
 2 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 35389b2af..0216f63a3 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -81,22 +81,4 @@ do {									\
 
 #include <asm-generic/barrier.h>
 
-/*
- * Make previous memory operations globally visible before
- * a WRMSR.
- *
- * MFENCE makes writes visible, but only affects load/store
- * instructions.  WRMSR is unfortunately not a load/store
- * instruction and is unaffected by MFENCE.  The LFENCE ensures
- * that the WRMSR is not reordered.
- *
- * Most WRMSRs are full serializing instructions themselves and
- * do not require this barrier.  This is only required for the
- * IA32_TSC_DEADLINE and X2APIC MSRs.
- */
-static inline void weak_wrmsr_fence(void)
-{
-	asm volatile("mfence; lfence" : : : "memory");
-}
-
 #endif /* _ASM_X86_BARRIER_H */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index a1e4fa58b..23707cb33 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -728,4 +728,23 @@ bool arch_is_platform_page(u64 paddr);
 #define arch_is_platform_page arch_is_platform_page
 #endif
 
+/*
+ * Make previous memory operations globally visible before
+ * a WRMSR.
+ *
+ * MFENCE makes writes visible, but only affects load/store
+ * instructions.  WRMSR is unfortunately not a load/store
+ * instruction and is unaffected by MFENCE.  The LFENCE ensures
+ * that the WRMSR is not reordered.
+ *
+ * Most WRMSRs are full serializing instructions themselves and
+ * do not require this barrier.  This is only required for the
+ * IA32_TSC_DEADLINE and X2APIC MSRs.
+ */
+static inline void weak_wrmsr_fence(void)
+{
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+		asm volatile("mfence; lfence" : : : "memory");
+}
+
 #endif /* _ASM_X86_PROCESSOR_H */
-- 
2.41.0.159.g0bfa463d37

From e87f6b361ff13249f3dccd03d319b64e128ba049 Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw@amazon.co.uk>
Date: Wed, 28 Jun 2023 11:42:45 +0100
Subject: [PATCH 16/17] mm/mmap: Fix error return in do_vmi_align_munmap()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

If mas_store_gfp() in the gather loop failed, the 'error' variable that
ultimately gets returned was not being set. In many cases, its original
value of -ENOMEM was still in place, and that was fine. But if VMAs had
been split at the start or end of the range, then 'error' could be zero.

Change to the 'error = foo(); if (error) goto …' idiom to fix the bug.

Also clean up a later case which avoided the same bug by *explicitly*
setting error = -ENOMEM right before calling the function that might
return -ENOMEM.

In a final cosmetic change, move the 'Point of no return' comment to
*after* the goto. That's been in the wrong place since the preallocation
was removed, and this new error path was added.

Fixes: 606c812eb1d5 ("mm/mmap: Fix error path in do_vmi_align_munmap()")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 mm/mmap.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index bc510361a..d3d939d84 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2476,7 +2476,8 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		}
 		vma_start_write(next);
 		mas_set_range(&mas_detach, next->vm_start, next->vm_end - 1);
-		if (mas_store_gfp(&mas_detach, next, GFP_KERNEL))
+		error = mas_store_gfp(&mas_detach, next, GFP_KERNEL);
+		if (error)
 			goto munmap_gather_failed;
 		vma_mark_detached(next, true);
 		if (next->vm_flags & VM_LOCKED)
@@ -2525,12 +2526,12 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		BUG_ON(count != test_count);
 	}
 #endif
-	/* Point of no return */
-	error = -ENOMEM;
 	vma_iter_set(vmi, start);
-	if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL))
+	error = vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL);
+	if (error)
 		goto clear_tree_failed;
 
+	/* Point of no return */
 	mm->locked_vm -= locked_vm;
 	mm->map_count -= count;
 	/*
-- 
2.41.0.159.g0bfa463d37

From dd346472853947aabc0203745f972b9ec06c3af2 Mon Sep 17 00:00:00 2001
From: Yin Fengwei <fengwei.yin@intel.com>
Date: Wed, 28 Jun 2023 12:43:03 +0800
Subject: [PATCH 17/17] readahead: correct the start and size in
 ondemand_readahead()

Commit 9425c591e06a ("page cache: fix page_cache_next/prev_miss off by
one") updated the page_cache_next_miss() to return the index beyond range.

But it breaks the start/size of ra in ondemand_readahead() because the
offset by one is accumulated to readahead_index.  As a consequence, not
best readahead order is picked.

Tracing of the order parameter of filemap_alloc_folio() showed:
     page order    : count     distribution
        0          : 892073   |                                        |
        1          : 0        |                                        |
        2          : 65120457 |****************************************|
        3          : 32914005 |********************                    |
        4          : 33020991 |********************                    |
with 9425c591e06a9.

With parent commit:
     page order    : count     distribution
        0          : 3417288  |****                                    |
        1          : 0        |                                        |
        2          : 877012   |*                                       |
        3          : 288      |                                        |
        4          : 5607522  |*******                                 |
        5          : 29974228 |****************************************|

Fix the issue by removing the offset by one when page_cache_next_miss()
returns no gaps in the range.

After the fix:
    page order     : count     distribution
        0          : 2598561  |***                                     |
        1          : 0        |                                        |
        2          : 687739   |                                        |
        3          : 288      |                                        |
        4          : 207210   |                                        |
        5          : 32628260 |****************************************|

Link: https://lkml.kernel.org/r/20230628044303.1412624-1-fengwei.yin@intel.com
Fixes: 9425c591e06a ("page cache: fix page_cache_next/prev_miss off by one")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202306211346.1e9ff03e-oliver.sang@intel.com
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/readahead.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/mm/readahead.c b/mm/readahead.c
index 47afbca1d..a93af7736 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -614,9 +614,17 @@ static void ondemand_readahead(struct readahead_control *ractl,
 				max_pages);
 		rcu_read_unlock();
 
-		if (!start || start - index > max_pages)
+		if (!start || start - index - 1 > max_pages)
 			return;
 
+		/*
+		 * If no gaps in the range, page_cache_next_miss() returns
+		 * index beyond range. Adjust it back to make sure
+		 * ractl->_index is updated correctly later.
+		 */
+		if ((start - index - 1) == max_pages)
+			start--;
+
 		ra->start = start;
 		ra->size = start - index;	/* old async_size */
 		ra->size += req_size;
-- 
2.41.0.159.g0bfa463d37

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