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: Felipe Balbi <balbi@ti.com>

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..0cdf89d32a15 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);