From 831a7b5002940f83de024d66c233f6953e32c900 Mon Sep 17 00:00:00 2001 From: Andreas Pape Date: Mon, 26 Sep 2022 18:58:13 +0200 Subject: [PATCH] ALSA: dmaengine: increment buffer pointer atomically [ 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 Signed-off-by: Eugeniu Rosca Link: https://lore.kernel.org/r/1664211493-11789-1-git-send-email-erosca@de.adit-jv.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- 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 8eb58c709b14..6f6da1128edc 100644 --- a/sound/core/pcm_dmaengine.c +++ b/sound/core/pcm_dmaengine.c @@ -139,12 +139,14 @@ 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); } -- 2.20.1