File 0003-pcm-Fallback-open-as-the-first-instance-fo... of Package alsa

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File 0003-pcm-Fallback-open-as-the-first-instance-for-dmix-co.patch of Package alsa (Revision e11bd280102f253778219b7734583edd)

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From fdba9e1bad8f769a6137e565471f0227f23a3132 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 14 Apr 2016 17:33:03 +0200
Subject: [PATCH] pcm: Fallback open as the first instance for dmix & co

dmix and other PCM plugins tries to open a secondary stream with
O_APPEND flag when the shmem was already attached by another.
However, when another streams have been already closed after the
shmem check, this open may return the error EBADFD, since the kernel
accepts O_APPEND only for the secondary streams.

This patch adds a workaround for such a case.  It just retries opening
the stream as the first instance (i.e. without O_APPEND flag).
This is basically safe behavior (the kernel takes care of races), even
we may do this even unconditionally.  But it's bad from the
performance POV, so we do it only when really needed.

Reported-by: Lars Lindqvist <lars.lindqvist@yandex.ru>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 src/pcm/pcm_dmix.c   | 8 ++++++++
 src/pcm/pcm_dshare.c | 8 ++++++++
 src/pcm/pcm_dsnoop.c | 8 ++++++++
 3 files changed, 24 insertions(+)

diff --git a/src/pcm/pcm_dmix.c b/src/pcm/pcm_dmix.c
index b26a5c790e7e..007d35664ce7 100644
--- a/src/pcm/pcm_dmix.c
+++ b/src/pcm/pcm_dmix.c
@@ -1020,6 +1020,7 @@ int snd_pcm_dmix_open(snd_pcm_t **pcmp, const char *name,
 	dmix->max_periods = opts->max_periods;
 	dmix->sync_ptr = snd_pcm_dmix_sync_ptr;
 
+ retry:
 	if (first_instance) {
 		/* recursion is already checked in
 		   snd_pcm_direct_get_slave_ipc_offset() */
@@ -1076,6 +1077,13 @@ int snd_pcm_dmix_open(snd_pcm_t **pcmp, const char *name,
 						 SND_PCM_APPEND,
 						 NULL);
 			if (ret < 0) {
+				/* all other streams have been closed;
+				 * retry as the first instance
+				 */
+				if (ret == -EBADFD) {
+					first_instance = 1;
+					goto retry;
+				}
 				SNDERR("unable to open slave");
 				goto _err;
 			}
diff --git a/src/pcm/pcm_dshare.c b/src/pcm/pcm_dshare.c
index 58e47bbeac67..adb3587a2869 100644
--- a/src/pcm/pcm_dshare.c
+++ b/src/pcm/pcm_dshare.c
@@ -690,6 +690,7 @@ int snd_pcm_dshare_open(snd_pcm_t **pcmp, const char *name,
 		break;
 	}
 
+ retry:
 	first_instance = ret = snd_pcm_direct_shm_create_or_connect(dshare);
 	if (ret < 0) {
 		SNDERR("unable to create IPC shm instance");
@@ -758,6 +759,13 @@ int snd_pcm_dshare_open(snd_pcm_t **pcmp, const char *name,
 						 SND_PCM_APPEND,
 						 NULL);
 			if (ret < 0) {
+				/* all other streams have been closed;
+				 * retry as the first instance
+				 */
+				if (ret == -EBADFD) {
+					first_instance = 1;
+					goto retry;
+				}
 				SNDERR("unable to open slave");
 				goto _err;
 			}
diff --git a/src/pcm/pcm_dsnoop.c b/src/pcm/pcm_dsnoop.c
index 576c35b111cd..8ff0ba57cb14 100644
--- a/src/pcm/pcm_dsnoop.c
+++ b/src/pcm/pcm_dsnoop.c
@@ -583,6 +583,7 @@ int snd_pcm_dsnoop_open(snd_pcm_t **pcmp, const char *name,
 		break;
 	}
 		
+ retry:
 	first_instance = ret = snd_pcm_direct_shm_create_or_connect(dsnoop);
 	if (ret < 0) {
 		SNDERR("unable to create IPC shm instance");
@@ -651,6 +652,13 @@ int snd_pcm_dsnoop_open(snd_pcm_t **pcmp, const char *name,
 						 SND_PCM_APPEND,
 						 NULL);
 			if (ret < 0) {
+				/* all other streams have been closed;
+				 * retry as the first instance
+				 */
+				if (ret == -EBADFD) {
+					first_instance = 1;
+					goto retry;
+				}
 				SNDERR("unable to open slave");
 				goto _err;
 			}
-- 
2.8.2

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File 0003-pcm-Fallback-open-as-the-first-instance-for-dmix-co.patch of Package alsa (Revision e11bd280102f253778219b7734583edd)

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