From fdba9e1bad8f769a6137e565471f0227f23a3132 Mon Sep 17 00:00:00 2001 From: Takashi Iwai 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 Signed-off-by: Takashi Iwai --- 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 b26a5c79..007d3566 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 58e47bbe..adb3587a 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 576c35b1..8ff0ba57 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; } -- 2.47.1