From: Bhupesh Sharma Date: Thu, 22 Mar 2012 03:50:37 +0000 (-0300) Subject: [media] usb: gadget/uvc: Remove non-required locking from 'uvc_queue_next_buffer... X-Git-Tag: firefly_0821_release~3680^2~275^2~2485 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=95faf82bd3ea607f8e1ca78930c49b71078266e6;p=firefly-linux-kernel-4.4.55.git [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 Acked-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- 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);