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authorHans Verkuil <hverkuil@xs4all.nl>2010-09-26 16:01:26 +0400
committerMauro Carvalho Chehab <mchehab@redhat.com>2010-10-21 07:06:14 +0400
commit0e0809a58869e3e422985f868ad5e0da1fc0ba85 (patch)
treee4895d60a050e15d6c4b21aa7dbc4090199efdf3 /drivers/media/video/videobuf-core.c
parent08bff03ed697a583612b62a6ac566bd5bce98012 (diff)
downloadlinux-0e0809a58869e3e422985f868ad5e0da1fc0ba85.tar.xz
V4L/DVB: videobuf: add queue argument to videobuf_waiton()
videobuf_waiton() must unlock and relock ext_lock if it has to wait. For that to happen it needs the videobuf_queue pointer. Don't attempt to unlock/relock q->ext_lock unless it was locked in the first place. vb->state has to be protected by a spinlock to be safe. This patch is based on code from Mauro Carvalho Chehab <mchehab@redhat.com>. [mchehab@redhat.com: add extra argument to a few missing places] Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/videobuf-core.c')
-rw-r--r--drivers/media/video/videobuf-core.c47
1 files changed, 34 insertions, 13 deletions
diff --git a/drivers/media/video/videobuf-core.c b/drivers/media/video/videobuf-core.c
index a32ef8eafc01..8979f91fa8e5 100644
--- a/drivers/media/video/videobuf-core.c
+++ b/drivers/media/video/videobuf-core.c
@@ -73,25 +73,46 @@ struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q)
}
EXPORT_SYMBOL_GPL(videobuf_alloc_vb);
-#define WAITON_CONDITION (vb->state != VIDEOBUF_ACTIVE &&\
- vb->state != VIDEOBUF_QUEUED)
-int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr)
+static int is_state_active_or_queued(struct videobuf_queue *q, struct videobuf_buffer *vb)
{
+ unsigned long flags;
+ bool rc;
+
+ spin_lock_irqsave(q->irqlock, flags);
+ rc = vb->state != VIDEOBUF_ACTIVE && vb->state != VIDEOBUF_QUEUED;
+ spin_unlock_irqrestore(q->irqlock, flags);
+ return rc;
+};
+
+int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
+ int non_blocking, int intr)
+{
+ bool is_ext_locked;
+ int ret = 0;
+
MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
if (non_blocking) {
- if (WAITON_CONDITION)
+ if (is_state_active_or_queued(q, vb))
return 0;
- else
- return -EAGAIN;
+ return -EAGAIN;
}
+ is_ext_locked = q->ext_lock && mutex_is_locked(q->ext_lock);
+
+ /* Release vdev lock to prevent this wait from blocking outside access to
+ the device. */
+ if (is_ext_locked)
+ mutex_unlock(q->ext_lock);
if (intr)
- return wait_event_interruptible(vb->done, WAITON_CONDITION);
+ ret = wait_event_interruptible(vb->done, is_state_active_or_queued(q, vb));
else
- wait_event(vb->done, WAITON_CONDITION);
+ wait_event(vb->done, is_state_active_or_queued(q, vb));
+ /* Relock */
+ if (is_ext_locked)
+ mutex_lock(q->ext_lock);
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(videobuf_waiton);
@@ -671,7 +692,7 @@ static int stream_next_buffer(struct videobuf_queue *q,
goto done;
buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
- retval = videobuf_waiton(buf, nonblocking, 1);
+ retval = videobuf_waiton(q, buf, nonblocking, 1);
if (retval < 0)
goto done;
@@ -799,7 +820,7 @@ static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
spin_lock_irqsave(q->irqlock, flags);
q->ops->buf_queue(q, q->read_buf);
spin_unlock_irqrestore(q->irqlock, flags);
- retval = videobuf_waiton(q->read_buf, 0, 0);
+ retval = videobuf_waiton(q, q->read_buf, 0, 0);
if (0 == retval) {
CALL(q, sync, q, q->read_buf);
if (VIDEOBUF_ERROR == q->read_buf->state)
@@ -911,7 +932,7 @@ ssize_t videobuf_read_one(struct videobuf_queue *q,
}
/* wait until capture is done */
- retval = videobuf_waiton(q->read_buf, nonblocking, 1);
+ retval = videobuf_waiton(q, q->read_buf, nonblocking, 1);
if (0 != retval)
goto done;
@@ -1061,7 +1082,7 @@ ssize_t videobuf_read_stream(struct videobuf_queue *q,
list_del(&q->read_buf->stream);
q->read_off = 0;
}
- rc = videobuf_waiton(q->read_buf, nonblocking, 1);
+ rc = videobuf_waiton(q, q->read_buf, nonblocking, 1);
if (rc < 0) {
if (0 == retval)
retval = rc;