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Commit 1a1e0a80 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Takashi Iwai
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sound: oss: dmasound: kill SLEEP() macro to avoid race 



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: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 76439c2a

sound/oss/dmasound/dmasound.h

+0 −1
Original line number Diff line number Diff line
@@ -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;

sound/oss/dmasound/dmasound_core.c

+19 −9
Original line number Diff line number Diff line
@@ -619,14 +619,26 @@ 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
@@ -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))

			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