From: Jiada Wang jiada_wang@mentor.com

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 --- sound/soc/sh/rcar/ssi.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/sound/soc/sh/rcar/ssi.c b/sound/soc/sh/rcar/ssi.c index fece1e5f..cbf3bf3 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; }