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platform_kernel-5.15
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Revert "ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock" 

This reverts commit 7777744e92.

It breaks the kernel abi so revert it for now.  We will add it back
later at the next kabi update.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I09fe568c08e50679adf930aadb79a8544789af81
This commit is contained in:
Greg Kroah-Hartman 2022-04-12 16:11:50 +02:00
parent 93d8bbeafb
commit 990e8bd6d9
4 changed files with 11 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/sound/pcm.h
View File

@ -399,7 +399,6 @@ struct snd_pcm_runtime {
struct fasync_struct *fasync;
bool stop_operating; /* sync_stop will be called */
struct mutex buffer_mutex; /* protect for buffer changes */
atomic_t buffer_accessing; /* >0: in r/w operation, <0: blocked */
/* -- private section -- */
void *private_data;

1
sound/core/pcm.c
View File

@ -970,7 +970,6 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
runtime->status->state = SNDRV_PCM_STATE_OPEN;
mutex_init(&runtime->buffer_mutex);
atomic_set(&runtime->buffer_accessing, 0);
substream->runtime = runtime;
substream->private_data = pcm->private_data;

9
sound/core/pcm_lib.c
View File

@ -1905,9 +1905,11 @@ static int wait_for_avail(struct snd_pcm_substream *substream,
if (avail >= runtime->twake)
break;
snd_pcm_stream_unlock_irq(substream);
mutex_unlock(&runtime->buffer_mutex);
tout = schedule_timeout(wait_time);
mutex_lock(&runtime->buffer_mutex);
snd_pcm_stream_lock_irq(substream);
set_current_state(TASK_INTERRUPTIBLE);
switch (runtime->status->state) {
@ -2201,6 +2203,7 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
nonblock = !!(substream->f_flags & O_NONBLOCK);
mutex_lock(&runtime->buffer_mutex);
snd_pcm_stream_lock_irq(substream);
err = pcm_accessible_state(runtime);
if (err < 0)
@ -2255,15 +2258,10 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
err = -EINVAL;
goto _end_unlock;
}
if (!atomic_inc_unless_negative(&runtime->buffer_accessing)) {
err = -EBUSY;
goto _end_unlock;
}
snd_pcm_stream_unlock_irq(substream);
err = writer(substream, appl_ofs, data, offset, frames,
transfer);
snd_pcm_stream_lock_irq(substream);
atomic_dec(&runtime->buffer_accessing);
if (err < 0)
goto _end_unlock;
err = pcm_accessible_state(runtime);
@ -2293,6 +2291,7 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
if (xfer > 0 && err >= 0)
snd_pcm_update_state(substream, runtime);
snd_pcm_stream_unlock_irq(substream);
mutex_unlock(&runtime->buffer_mutex);
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
EXPORT_SYMBOL(__snd_pcm_lib_xfer);

39
sound/core/pcm_native.c
View File

@ -672,24 +672,6 @@ static int snd_pcm_hw_params_choose(struct snd_pcm_substream *pcm,
return 0;
}
/* acquire buffer_mutex; if it's in r/w operation, return -EBUSY, otherwise
* block the further r/w operations
*/
static int snd_pcm_buffer_access_lock(struct snd_pcm_runtime *runtime)
{
if (!atomic_dec_unless_positive(&runtime->buffer_accessing))
return -EBUSY;
mutex_lock(&runtime->buffer_mutex);
return 0; /* keep buffer_mutex, unlocked by below */
}
/* release buffer_mutex and clear r/w access flag */
static void snd_pcm_buffer_access_unlock(struct snd_pcm_runtime *runtime)
{
mutex_unlock(&runtime->buffer_mutex);
atomic_inc(&runtime->buffer_accessing);
}
#if IS_ENABLED(CONFIG_SND_PCM_OSS)
#define is_oss_stream(substream) ((substream)->oss.oss)
#else
@ -700,16 +682,14 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
struct snd_pcm_runtime *runtime;
int err, usecs;
int err = 0, usecs;
unsigned int bits;
snd_pcm_uframes_t frames;
if (PCM_RUNTIME_CHECK(substream))
return -ENXIO;
runtime = substream->runtime;
err = snd_pcm_buffer_access_lock(runtime);
if (err < 0)
return err;
mutex_lock(&runtime->buffer_mutex);
snd_pcm_stream_lock_irq(substream);
switch (runtime->status->state) {
case SNDRV_PCM_STATE_OPEN:
@ -827,7 +807,7 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
snd_pcm_lib_free_pages(substream);
}
unlock:
snd_pcm_buffer_access_unlock(runtime);
mutex_unlock(&runtime->buffer_mutex);
return err;
}
@ -872,9 +852,7 @@ static int snd_pcm_hw_free(struct snd_pcm_substream *substream)
if (PCM_RUNTIME_CHECK(substream))
return -ENXIO;
runtime = substream->runtime;
result = snd_pcm_buffer_access_lock(runtime);
if (result < 0)
return result;
mutex_lock(&runtime->buffer_mutex);
snd_pcm_stream_lock_irq(substream);
switch (runtime->status->state) {
case SNDRV_PCM_STATE_SETUP:
@ -893,7 +871,7 @@ static int snd_pcm_hw_free(struct snd_pcm_substream *substream)
snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
cpu_latency_qos_remove_request(&substream->latency_pm_qos_req);
unlock:
snd_pcm_buffer_access_unlock(runtime);
mutex_unlock(&runtime->buffer_mutex);
return result;
}
@ -1378,15 +1356,12 @@ static int snd_pcm_action_nonatomic(const struct action_ops *ops,
/* Guarantee the group members won't change during non-atomic action */
down_read(&snd_pcm_link_rwsem);
res = snd_pcm_buffer_access_lock(substream->runtime);
if (res < 0)
goto unlock;
mutex_lock(&substream->runtime->buffer_mutex);
if (snd_pcm_stream_linked(substream))
res = snd_pcm_action_group(ops, substream, state, false);
else
res = snd_pcm_action_single(ops, substream, state);
snd_pcm_buffer_access_unlock(substream->runtime);
unlock:
mutex_unlock(&substream->runtime->buffer_mutex);
up_read(&snd_pcm_link_rwsem);
return res;
}