[PATCH 5.8 047/118] ASoC: soc-core: add snd_soc_find_dai_with_mutex()

Greg Kroah-Hartman
2020-09-21T16:56:56Z

From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

[ Upstream commit 20d9fdee72dfaa1fa7588c7a846283bd740e7157 ]

commit 25612477d20b52 ("ASoC: soc-dai: set dai_link dpcm_ flags with a helper")
added snd_soc_dai_link_set_capabilities().
But it is using snd_soc_find_dai() (A) which is required client_mutex (B).
And client_mutex is soc-core.c local.

struct snd_soc_dai *snd_soc_find_dai(xxx)
{
...
(B) lockdep_assert_held(&client_mutex);
...
}

void snd_soc_dai_link_set_capabilities(xxx)
{
...
for_each_pcm_streams(direction) {
...
for_each_link_cpus(dai_link, i, cpu) {
(A) dai = snd_soc_find_dai(cpu);
...
}
...
for_each_link_codecs(dai_link, i, codec) {
(A) dai = snd_soc_find_dai(codec);
...
}
}
...
}

Because of these background, we will get WARNING if .config has CONFIG_LOCKDEP.

WARNING: CPU: 2 PID: 53 at sound/soc/soc-core.c:814 snd_soc_find_dai+0xf8/0x100
CPU: 2 PID: 53 Comm: kworker/2:1 Not tainted 5.7.0-rc1+ #328
Hardware name: Renesas H3ULCB Kingfisher board based on r8a77951 (DT)
Workqueue: events deferred_probe_work_func
pstate: 60000005 (nZCv daif -PAN -UAO)
pc : snd_soc_find_dai+0xf8/0x100
lr : snd_soc_find_dai+0xf4/0x100
...
Call trace:
snd_soc_find_dai+0xf8/0x100
snd_soc_dai_link_set_capabilities+0xa0/0x16c
graph_dai_link_of_dpcm+0x390/0x3c0
graph_for_each_link+0x134/0x200
graph_probe+0x144/0x230
platform_drv_probe+0x5c/0xb0
really_probe+0xe4/0x430
driver_probe_device+0x60/0xf4

snd_soc_find_dai() will be used from (X) CPU/Codec/Platform driver with
mutex lock, and (Y) Card driver without mutex lock.
This snd_soc_dai_link_set_capabilities() is for Card driver,
this means called without mutex.
This patch adds snd_soc_find_dai_with_mutex() to solve it.

Fixes: 25612477d20b52 ("ASoC: soc-dai: set dai_link dpcm_ flags with a helper")
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87blixvuab.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/sound/soc.h | 2 ++
sound/soc/soc-core.c | 13 +++++++++++++
sound/soc/soc-dai.c | 4 ++--
3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index 3ce7f0f5aa929..bc6ecb10c7649 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -1373,6 +1373,8 @@ void snd_soc_unregister_dai(struct snd_soc_dai *dai);

struct snd_soc_dai *snd_soc_find_dai(
const struct snd_soc_dai_link_component *dlc);
+struct snd_soc_dai *snd_soc_find_dai_with_mutex(
+ const struct snd_soc_dai_link_component *dlc);

#include <sound/soc-dai.h>

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index f1d641cd48da9..20ca1d38b4b87 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -834,6 +834,19 @@ struct snd_soc_dai *snd_soc_find_dai(
}
EXPORT_SYMBOL_GPL(snd_soc_find_dai);

+struct snd_soc_dai *snd_soc_find_dai_with_mutex(
+ const struct snd_soc_dai_link_component *dlc)
+{
+ struct snd_soc_dai *dai;
+
+ mutex_lock(&client_mutex);
+ dai = snd_soc_find_dai(dlc);
+ mutex_unlock(&client_mutex);
+
+ return dai;
+}
+EXPORT_SYMBOL_GPL(snd_soc_find_dai_with_mutex);
+
static int soc_dai_link_sanity_check(struct snd_soc_card *card,
struct snd_soc_dai_link *link)
{
diff --git a/sound/soc/soc-dai.c b/sound/soc/soc-dai.c
index cecbbed2de9d5..0e04ad7689cd9 100644
--- a/sound/soc/soc-dai.c
+++ b/sound/soc/soc-dai.c
@@ -410,14 +410,14 @@ void snd_soc_dai_link_set_capabilities(struct snd_soc_dai_link *dai_link)
supported_codec = false;

for_each_link_cpus(dai_link, i, cpu) {
- dai = snd_soc_find_dai(cpu);
+ dai = snd_soc_find_dai_with_mutex(cpu);
if (dai && snd_soc_dai_stream_valid(dai, direction)) {
supported_cpu = true;
break;
}
}
for_each_link_codecs(dai_link, i, codec) {
- dai = snd_soc_find_dai(codec);
+ dai = snd_soc_find_dai_with_mutex(codec);
if (dai && snd_soc_dai_stream_valid(dai, direction)) {
supported_codec = true;
break;
--
2.25.1