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V4L/DVB (7488): videobuf: Simplify videobuf_waiton logic and possibly avoid missed wakeup

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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: Brandon Philips <bphilips@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Brandon Philips 2008-04-02 18:10:59 -03:00 committed by Mauro Carvalho Chehab
parent b608f4323a
commit 009a90597e
1 changed files with 15 additions and 22 deletions
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37
drivers/media/video/videobuf-core.c
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@ -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 (non_blocking) {
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,