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authorGregory CLEMENT <gregory.clement@bootlin.com>2019-09-18 12:03:44 +0200
committerMark Brown <broonie@kernel.org>2019-09-18 11:12:24 +0100
commit0dce49efc70536a8c3b4bb5354a71b727ba31b80 (patch)
tree5ad1e15f8f6188b90de37bb6f0ab025ad07b106b
parenta0a4bf57a977ed37bcbdfc8027a44485fe086a3d (diff)
ASoC: atmel_ssc_dai: Remove wrong spinlock usage
A potential bug was reported in the email "[BUG] atmel_ssc_dai: a possible sleep-in-atomic bug in atmel_ssc_shutdown"[1] Indeed in the function atmel_ssc_shutdown() free_irq() was called in a critical section protected by spinlock. However this spinlock is only used in atmel_ssc_shutdown() and atmel_ssc_startup() functions. After further analysis, it occurred that the call to these function are already protected by mutex used on the calling functions. Then we can remove the spinlock which will fix this bug as a side effect. Thanks to this patch the following message disappears: "BUG: sleeping function called from invalid context at kernel/locking/mutex.c:909" [1]: https://www.spinics.net/lists/alsa-devel/msg71286.html Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com> Link: https://lore.kernel.org/r/20190918100344.23629-1-gregory.clement@bootlin.com Signed-off-by: Mark Brown <broonie@kernel.org>
-rw-r--r--sound/soc/atmel/atmel_ssc_dai.c12
-rw-r--r--sound/soc/atmel/atmel_ssc_dai.h1
2 files changed, 2 insertions, 11 deletions
diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
index 48e9eef34c0f..ca603397651c 100644
--- a/sound/soc/atmel/atmel_ssc_dai.c
+++ b/sound/soc/atmel/atmel_ssc_dai.c
@@ -116,19 +116,16 @@ static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = {
static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = {
{
.name = "ssc0",
- .lock = __SPIN_LOCK_UNLOCKED(ssc_info[0].lock),
.dir_mask = SSC_DIR_MASK_UNUSED,
.initialized = 0,
},
{
.name = "ssc1",
- .lock = __SPIN_LOCK_UNLOCKED(ssc_info[1].lock),
.dir_mask = SSC_DIR_MASK_UNUSED,
.initialized = 0,
},
{
.name = "ssc2",
- .lock = __SPIN_LOCK_UNLOCKED(ssc_info[2].lock),
.dir_mask = SSC_DIR_MASK_UNUSED,
.initialized = 0,
},
@@ -317,13 +314,10 @@ static int atmel_ssc_startup(struct snd_pcm_substream *substream,
snd_soc_dai_set_dma_data(dai, substream, dma_params);
- spin_lock_irq(&ssc_p->lock);
- if (ssc_p->dir_mask & dir_mask) {
- spin_unlock_irq(&ssc_p->lock);
+ if (ssc_p->dir_mask & dir_mask)
return -EBUSY;
- }
+
ssc_p->dir_mask |= dir_mask;
- spin_unlock_irq(&ssc_p->lock);
return 0;
}
@@ -355,7 +349,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
dir_mask = 1 << dir;
- spin_lock_irq(&ssc_p->lock);
ssc_p->dir_mask &= ~dir_mask;
if (!ssc_p->dir_mask) {
if (ssc_p->initialized) {
@@ -369,7 +362,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
ssc_p->forced_divider = 0;
}
- spin_unlock_irq(&ssc_p->lock);
/* Shutdown the SSC clock. */
pr_debug("atmel_ssc_dai: Stopping clock\n");
diff --git a/sound/soc/atmel/atmel_ssc_dai.h b/sound/soc/atmel/atmel_ssc_dai.h
index ae764cb541c7..3470b966e449 100644
--- a/sound/soc/atmel/atmel_ssc_dai.h
+++ b/sound/soc/atmel/atmel_ssc_dai.h
@@ -93,7 +93,6 @@ struct atmel_ssc_state {
struct atmel_ssc_info {
char *name;
struct ssc_device *ssc;
- spinlock_t lock; /* lock for dir_mask */
unsigned short dir_mask; /* 0=unused, 1=playback, 2=capture */
unsigned short initialized; /* true if SSC has been initialized */
unsigned short daifmt;