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Commit 93c86281 authored by Andreas Pape's avatar Andreas Pape Committed by Greg Kroah-Hartman
Browse files

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: e7f73a16 ("ASoC: Add dmaengine PCM helper functions")
Signed-off-by: default avatarAndreas Pape <apape@de.adit-jv.com>
Signed-off-by: default avatarEugeniu Rosca <erosca@de.adit-jv.com>
Link: https://lore.kernel.org/r/1664211493-11789-1-git-send-email-erosca@de.adit-jv.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 6c85495e

sound/core/pcm_dmaengine.c

+5 −3
Original line number Diff line number Diff line
@@ -130,12 +130,14 @@ 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);

}