From: Takashi Iwai tiwai@suse.de
[ Upstream commit b2ae80663008a7662febe7d13f14ea1b2eb0cd51 ]
When more than one FE is connected to a BE, e.g. in a mixing use case, the BE can be triggered multiple times when the FE are opened/started concurrently. This race condition is problematic in the case of SoundWire BE dailinks, and this is not desirable in a general case.
This patch relies on the existing BE PCM lock, which takes atomicity into account. The locking model assumes that all interactions start with the FE, so that there is no deadlock between FE and BE locks.
Signed-off-by: Takashi Iwai tiwai@suse.de [test, checkpatch fix and clarification of commit message by plbossart] Signed-off-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com Reviewed-by: Kai Vehmanen kai.vehmanen@linux.intel.com Reviewed-by: Bard Liao yung-chuan.liao@linux.intel.com Reviewed-by: Ranjani Sridharan ranjani.sridharan@linux.intel.com Link: https://lore.kernel.org/r/20211207173745.15850-5-pierre-louis.bossart@linux.... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- sound/soc/soc-pcm.c | 46 ++++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 17 deletions(-)
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c index d26a1f12c513a..7c7ae69f9410d 100644 --- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -46,12 +46,18 @@ static inline void snd_soc_dpcm_stream_lock_irq(struct snd_soc_pcm_runtime *rtd, snd_pcm_stream_lock_irq(snd_soc_dpcm_get_substream(rtd, stream)); }
+#define snd_soc_dpcm_stream_lock_irqsave(rtd, stream, flags) \ + snd_pcm_stream_lock_irqsave(snd_soc_dpcm_get_substream(rtd, stream), flags) + static inline void snd_soc_dpcm_stream_unlock_irq(struct snd_soc_pcm_runtime *rtd, int stream) { snd_pcm_stream_unlock_irq(snd_soc_dpcm_get_substream(rtd, stream)); }
+#define snd_soc_dpcm_stream_unlock_irqrestore(rtd, stream, flags) \ + snd_pcm_stream_unlock_irqrestore(snd_soc_dpcm_get_substream(rtd, stream), flags) + #define DPCM_MAX_BE_USERS 8
static inline const char *soc_cpu_dai_name(struct snd_soc_pcm_runtime *rtd) @@ -2094,6 +2100,7 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, { struct snd_soc_pcm_runtime *be; struct snd_soc_dpcm *dpcm; + unsigned long flags; int ret = 0;
for_each_dpcm_be(fe, stream, dpcm) { @@ -2102,9 +2109,11 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, be = dpcm->be; be_substream = snd_soc_dpcm_get_substream(be, stream);
+ snd_soc_dpcm_stream_lock_irqsave(be, stream, flags); + /* is this op for this BE ? */ if (!snd_soc_dpcm_be_can_update(fe, be, stream)) - continue; + goto next;
dev_dbg(be->dev, "ASoC: trigger BE %s cmd %d\n", be->dai_link->name, cmd); @@ -2114,77 +2123,80 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_PREPARE) && (be->dpcm[stream].state != SND_SOC_DPCM_STATE_STOP) && (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED)) - continue; + goto next;
ret = soc_pcm_trigger(be_substream, cmd); if (ret) - goto end; + goto next;
be->dpcm[stream].state = SND_SOC_DPCM_STATE_START; break; case SNDRV_PCM_TRIGGER_RESUME: if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_SUSPEND)) - continue; + goto next;
ret = soc_pcm_trigger(be_substream, cmd); if (ret) - goto end; + goto next;
be->dpcm[stream].state = SND_SOC_DPCM_STATE_START; break; case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED)) - continue; + goto next;
ret = soc_pcm_trigger(be_substream, cmd); if (ret) - goto end; + goto next;
be->dpcm[stream].state = SND_SOC_DPCM_STATE_START; break; case SNDRV_PCM_TRIGGER_STOP: if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_START) && (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED)) - continue; + goto next;
if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream)) - continue; + goto next;
ret = soc_pcm_trigger(be_substream, cmd); if (ret) - goto end; + goto next;
be->dpcm[stream].state = SND_SOC_DPCM_STATE_STOP; break; case SNDRV_PCM_TRIGGER_SUSPEND: if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START) - continue; + goto next;
if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream)) - continue; + goto next;
ret = soc_pcm_trigger(be_substream, cmd); if (ret) - goto end; + goto next;
be->dpcm[stream].state = SND_SOC_DPCM_STATE_SUSPEND; break; case SNDRV_PCM_TRIGGER_PAUSE_PUSH: if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START) - continue; + goto next;
if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream)) - continue; + goto next;
ret = soc_pcm_trigger(be_substream, cmd); if (ret) - goto end; + goto next;
be->dpcm[stream].state = SND_SOC_DPCM_STATE_PAUSED; break; } +next: + snd_soc_dpcm_stream_unlock_irqrestore(be, stream, flags); + if (ret) + break; } -end: if (ret < 0) dev_err(fe->dev, "ASoC: %s() failed at %s (%d)\n", __func__, be->dai_link->name, ret);