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authorBhupesh Sharma <bhupesh.sharma@st.com>2012-03-22 00:50:37 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-04-10 15:46:02 -0300
commit95faf82bd3ea607f8e1ca78930c49b71078266e6 (patch)
tree325a5529c3c5b4d46dcbaecb3800f844321918ca /drivers/usb/gadget/uvc_queue.c
parent7cfce77d779f43299c1cfeddd72462fed596c168 (diff)
[media] usb: gadget/uvc: Remove non-required locking from 'uvc_queue_next_buffer' routine
This patch removes the non-required spinlock acquire/release calls on 'queue_irqlock' from 'uvc_queue_next_buffer' routine. This routine is called from 'video->encode' function (which translates to either 'uvc_video_encode_bulk' or 'uvc_video_encode_isoc') in 'uvc_video.c'. As, the 'video->encode' routines are called with 'queue_irqlock' already held, so acquiring a 'queue_irqlock' again in 'uvc_queue_next_buffer' routine causes a spin lock recursion. Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/usb/gadget/uvc_queue.c')
-rw-r--r--drivers/usb/gadget/uvc_queue.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/drivers/usb/gadget/uvc_queue.c b/drivers/usb/gadget/uvc_queue.c
index d776adb2da67..104ae9c81251 100644
--- a/drivers/usb/gadget/uvc_queue.c
+++ b/drivers/usb/gadget/uvc_queue.c
@@ -543,11 +543,11 @@ done:
return ret;
}
+/* called with &queue_irqlock held.. */
static struct uvc_buffer *
uvc_queue_next_buffer(struct uvc_video_queue *queue, struct uvc_buffer *buf)
{
struct uvc_buffer *nextbuf;
- unsigned long flags;
if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
buf->buf.length != buf->buf.bytesused) {
@@ -556,14 +556,12 @@ uvc_queue_next_buffer(struct uvc_video_queue *queue, struct uvc_buffer *buf)
return buf;
}
- spin_lock_irqsave(&queue->irqlock, flags);
list_del(&buf->queue);
if (!list_empty(&queue->irqqueue))
nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
queue);
else
nextbuf = NULL;
- spin_unlock_irqrestore(&queue->irqlock, flags);
buf->buf.sequence = queue->sequence++;
do_gettimeofday(&buf->buf.timestamp);

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