diff options
| author | Jiada Wang <jiada_wang@mentor.com> | 2017-12-07 22:15:38 -0800 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2017-12-08 18:51:32 +0000 |
| commit | 33f801366bdf3f8b67dfe325b84f4051a090d01e (patch) | |
| tree | 0f322e9b274164c3bd6e3726cb93ec438deaa493 | |
| parent | a91d7fb97092d6b840af5899ded3b389603fd7f1 (diff) | |
| download | linux-33f801366bdf3f8b67dfe325b84f4051a090d01e.tar.bz2 | |
ASoC: rsnd: ssi: fix race condition in rsnd_ssi_pointer_update
Currently there is race condition between set of byte_pos and wrap
it around when new buffer starts. If .pointer is called in-between
it will result in inconsistent pointer position be returned
from .pointer callback.
This patch increments buffer pointer atomically to avoid this issue.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Reviewed-by: Takashi Sakamoto <takashi.sakamoto@miraclelinux.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | sound/soc/sh/rcar/ssi.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/sound/soc/sh/rcar/ssi.c b/sound/soc/sh/rcar/ssi.c index fece1e5f582f..cbf3bf312d23 100644 --- a/sound/soc/sh/rcar/ssi.c +++ b/sound/soc/sh/rcar/ssi.c @@ -446,25 +446,29 @@ static bool rsnd_ssi_pointer_update(struct rsnd_mod *mod, int byte) { struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod); + bool ret = false; + int byte_pos; - ssi->byte_pos += byte; + byte_pos = ssi->byte_pos + byte; - if (ssi->byte_pos >= ssi->next_period_byte) { + if (byte_pos >= ssi->next_period_byte) { struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io); ssi->period_pos++; ssi->next_period_byte += ssi->byte_per_period; if (ssi->period_pos >= runtime->periods) { - ssi->byte_pos = 0; + byte_pos = 0; ssi->period_pos = 0; ssi->next_period_byte = ssi->byte_per_period; } - return true; + ret = true; } - return false; + WRITE_ONCE(ssi->byte_pos, byte_pos); + + return ret; } /* @@ -838,7 +842,7 @@ static int rsnd_ssi_pointer(struct rsnd_mod *mod, struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod); struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io); - *pointer = bytes_to_frames(runtime, ssi->byte_pos); + *pointer = bytes_to_frames(runtime, READ_ONCE(ssi->byte_pos)); return 0; } |