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Commit 009a9059 authored by Brandon Philips's avatar Brandon Philips Committed by Mauro Carvalho Chehab
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V4L/DVB (7488): videobuf: Simplify videobuf_waiton logic and possibly avoid missed wakeup 

Possible missed wakeup- use kernel helpers for wait queues
  http://www.mail-archive.com/linux-usb-devel@lists.sourceforge.net/msg27983.html



Signed-off-by: default avatarBrandon Philips <bphilips@suse.de>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent b608f432

drivers/media/video/videobuf-core.c

+15 −22
Original line number Diff line number Diff line
@@ -64,32 +64,25 @@ void *videobuf_alloc(struct videobuf_queue *q) 
	return vb;

}



#define WAITON_CONDITION (vb->state != VIDEOBUF_ACTIVE &&\

				vb->state != VIDEOBUF_QUEUED)

int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr)

{

	int retval = 0;

	DECLARE_WAITQUEUE(wait, current);



	MAGIC_CHECK(vb->magic, MAGIC_BUFFER);

	add_wait_queue(&vb->done, &wait);

	while (vb->state == VIDEOBUF_ACTIVE || vb->state == VIDEOBUF_QUEUED) {



	if (non_blocking) {

			retval = -EAGAIN;

			break;

		}

		set_current_state(intr  ? TASK_INTERRUPTIBLE

					: TASK_UNINTERRUPTIBLE);

		if (vb->state == VIDEOBUF_ACTIVE ||

		    vb->state == VIDEOBUF_QUEUED)

			schedule();

		set_current_state(TASK_RUNNING);

		if (intr && signal_pending(current)) {

			dprintk(1, "buffer waiton: -EINTR\n");

			retval = -EINTR;

			break;

		}

		if (WAITON_CONDITION)

			return 0;

		else

			return -EAGAIN;

	}

	remove_wait_queue(&vb->done, &wait);

	return retval;



	if (intr)

		return wait_event_interruptible(vb->done, WAITON_CONDITION);

	else

		wait_event(vb->done, WAITON_CONDITION);



	return 0;

}



int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,