From: Andreas Pape apape@de.adit-jv.com
[ Upstream commit d1c442019594692c64a70a86ad88eb5b6db92216 ]
Setting pointer and afterwards checking for wraparound leads to the possibility of returning the inconsistent pointer position.
This patch increments buffer pointer atomically to avoid this issue.
Fixes: e7f73a1613567a ("ASoC: Add dmaengine PCM helper functions") Signed-off-by: Andreas Pape apape@de.adit-jv.com Signed-off-by: Eugeniu Rosca erosca@de.adit-jv.com Link: https://lore.kernel.org/r/1664211493-11789-1-git-send-email-erosca@de.adit-j... Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- sound/core/pcm_dmaengine.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c index af6f717e1e7e..c6ccb75036ae 100644 --- a/sound/core/pcm_dmaengine.c +++ b/sound/core/pcm_dmaengine.c @@ -131,12 +131,14 @@ EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data);
static void dmaengine_pcm_dma_complete(void *arg) { + unsigned int new_pos; struct snd_pcm_substream *substream = arg; struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
- prtd->pos += snd_pcm_lib_period_bytes(substream); - if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream)) - prtd->pos = 0; + new_pos = prtd->pos + snd_pcm_lib_period_bytes(substream); + if (new_pos >= snd_pcm_lib_buffer_bytes(substream)) + new_pos = 0; + prtd->pos = new_pos;
snd_pcm_period_elapsed(substream); }