From: Andreas Pape Date: Mon, 26 Sep 2022 16:58:13 +0000 (+0200) Subject: ALSA: dmaengine: increment buffer pointer atomically X-Git-Tag: Proxmox-5.15.83-1~1423 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=d06ab8b2dd7d3b3686763bf3ed54666015c0d54d;p=mirror_ubuntu-jammy-kernel.git ALSA: dmaengine: increment buffer pointer atomically BugLink: https://bugs.launchpad.net/bugs/1996825 [ 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 Signed-off-by: Kamal Mostafa Signed-off-by: Stefan Bader --- diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c index 1fc2fa077574..0fe93b423c4e 100644 --- a/sound/core/pcm_dmaengine.c +++ b/sound/core/pcm_dmaengine.c @@ -132,12 +132,14 @@ 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); }