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Commit 3cdadc50 authored by Richard Zidlicky's avatar Richard Zidlicky Committed by Mauro Carvalho Chehab
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V4L/DVB: dvb: fix smscore_getbuffer() logic 



Drivers shouldn't sleep while holding a spinlock. A previous workaround
were to release the spinlock before callinc schedule().

This patch uses a different approach: it just waits for the
siano hardware to answer.

Signed-off-by: default avatarRichard Zidlicky <rz@linux-m68k.org>
Cc: stable@kernel.org
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 970d14c6

drivers/media/dvb/siano/smscoreapi.c

+12 −19
Original line number Diff line number Diff line
@@ -1098,33 +1098,26 @@ EXPORT_SYMBOL_GPL(smscore_onresponse); 
 *

 * @return pointer to descriptor on success, NULL on error.

 */

struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev)



struct smscore_buffer_t *get_entry(struct smscore_device_t *coredev)

{

	struct smscore_buffer_t *cb = NULL;

	unsigned long flags;



	DEFINE_WAIT(wait);



	spin_lock_irqsave(&coredev->bufferslock, flags);



	/* This function must return a valid buffer, since the buffer list is

	 * finite, we check that there is an available buffer, if not, we wait

	 * until such buffer become available.

	 */



	prepare_to_wait(&coredev->buffer_mng_waitq, &wait, TASK_INTERRUPTIBLE);

	if (list_empty(&coredev->buffers)) {

	if (!list_empty(&coredev->buffers)) {

		cb = (struct smscore_buffer_t *) coredev->buffers.next;

		list_del(&cb->entry);

	}

	spin_unlock_irqrestore(&coredev->bufferslock, flags);

		schedule();

		spin_lock_irqsave(&coredev->bufferslock, flags);

	return cb;

}



	finish_wait(&coredev->buffer_mng_waitq, &wait);



	cb = (struct smscore_buffer_t *) coredev->buffers.next;

	list_del(&cb->entry);

struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev)

{

	struct smscore_buffer_t *cb = NULL;



	spin_unlock_irqrestore(&coredev->bufferslock, flags);

	wait_event(coredev->buffer_mng_waitq, (cb = get_entry(coredev)));



	return cb;

}