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sound: oss: dmasound: kill SLEEP() macro to avoid race

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The use of interruptible_sleep_on_timeout in the dmasound driver
is questionable and we want to kill off all sleep_on variants.
This replaces the calls with wait_event_interruptible_timeout
where possible, to wait for a particular event instead of blocking
in a racy way. In the sq_write function, the easiest solution is
an open-coded prepare_to_wait loop.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Arnd Bergmann 2014-01-02 13:07:50 +01:00 committed by Takashi Iwai
parent 76439c2ac6
commit 1a1e0a80ce
2 changed files with 19 additions and 10 deletions
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1
sound/oss/dmasound/dmasound.h
View File

@ -239,7 +239,6 @@ struct sound_queue {
int busy, syncing, xruns, died;
};
#define SLEEP(queue) interruptible_sleep_on_timeout(&queue, HZ)
#define WAKE_UP(queue) (wake_up_interruptible(&queue))
extern struct sound_queue dmasound_write_sq;

28
sound/oss/dmasound/dmasound_core.c
View File

@ -619,15 +619,27 @@ static ssize_t sq_write(struct file *file, const char __user *src, size_t uLeft,
}
while (uLeft) {
DEFINE_WAIT(wait);
while (write_sq.count >= write_sq.max_active) {
prepare_to_wait(&write_sq.action_queue, &wait, TASK_INTERRUPTIBLE);
sq_play();
if (write_sq.non_blocking)
if (write_sq.non_blocking) {
finish_wait(&write_sq.action_queue, &wait);
return uWritten > 0 ? uWritten : -EAGAIN;
SLEEP(write_sq.action_queue);
if (signal_pending(current))
}
if (write_sq.count < write_sq.max_active)
break;
schedule_timeout(HZ);
if (signal_pending(current)) {
finish_wait(&write_sq.action_queue, &wait);
return uWritten > 0 ? uWritten : -EINTR;
}
}
finish_wait(&write_sq.action_queue, &wait);
/* Here, we can avoid disabling the interrupt by first
* copying and translating the data, and then updating
* the write_sq variables. Until this is done, the interrupt
@ -707,11 +719,8 @@ static int sq_open2(struct sound_queue *sq, struct file *file, fmode_t mode,
if (file->f_flags & O_NONBLOCK)
return rc;
rc = -EINTR;
while (sq->busy) {
SLEEP(sq->open_queue);
if (signal_pending(current))
return rc;
}
if (wait_event_interruptible(sq->open_queue, !sq->busy))
return rc;
rc = 0;
#else
/* OSS manual says we will return EBUSY regardless
@ -844,7 +853,8 @@ static int sq_fsync(void)
sq_play(); /* there may be an incomplete frame waiting */
while (write_sq.active) {
SLEEP(write_sq.sync_queue);
wait_event_interruptible_timeout(write_sq.sync_queue,
!write_sq.active, HZ);
if (signal_pending(current)) {
/* While waiting for audio output to drain, an
* interrupt occurred. Stop audio output immediately