Commit 1698a7f1 authored by Alexandre Courbot's avatar Alexandre Courbot Committed by Mauro Carvalho Chehab
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media: v4l2-mem2mem: simplify poll logic 



Factorize redundant checks into a single code block, remove unneeded
checks (a buffer in done_list is necessarily in the DONE or ERROR
state), and we end up with a much simpler version of this function.

Signed-off-by: default avatarAlexandre Courbot <gnurou@gmail.com>
Reviewed-by: default avatarEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent 566463af

drivers/media/v4l2-core/v4l2-mem2mem.c

+5 −21
Original line number Diff line number Diff line
@@ -882,7 +882,6 @@ static __poll_t v4l2_m2m_poll_for_data(struct file *file, 
				       struct poll_table_struct *wait)

{

	struct vb2_queue *src_q, *dst_q;

	struct vb2_buffer *src_vb = NULL, *dst_vb = NULL;

	__poll_t rc = 0;

	unsigned long flags;
@@ -903,32 +902,17 @@ static __poll_t v4l2_m2m_poll_for_data(struct file *file, 
	     list_empty(&dst_q->queued_list)))

		return EPOLLERR;



	spin_lock_irqsave(&dst_q->done_lock, flags);

	if (list_empty(&dst_q->done_list)) {

		/*

		 * If the last buffer was dequeued from the capture queue,

		 * return immediately. DQBUF will return -EPIPE.

		 */

		if (dst_q->last_buffer_dequeued)

			rc |= EPOLLIN | EPOLLRDNORM;

	}

	spin_unlock_irqrestore(&dst_q->done_lock, flags);



	spin_lock_irqsave(&src_q->done_lock, flags);

	if (!list_empty(&src_q->done_list))

		src_vb = list_first_entry(&src_q->done_list, struct vb2_buffer,

						done_entry);

	if (src_vb && (src_vb->state == VB2_BUF_STATE_DONE

			|| src_vb->state == VB2_BUF_STATE_ERROR))

		rc |= EPOLLOUT | EPOLLWRNORM;

	spin_unlock_irqrestore(&src_q->done_lock, flags);



	spin_lock_irqsave(&dst_q->done_lock, flags);

	if (!list_empty(&dst_q->done_list))

		dst_vb = list_first_entry(&dst_q->done_list, struct vb2_buffer,

						done_entry);

	if (dst_vb && (dst_vb->state == VB2_BUF_STATE_DONE

			|| dst_vb->state == VB2_BUF_STATE_ERROR))

	/*

	 * If the last buffer was dequeued from the capture queue, signal

	 * userspace. DQBUF(CAPTURE) will return -EPIPE.

	 */

	if (!list_empty(&dst_q->done_list) || dst_q->last_buffer_dequeued)

		rc |= EPOLLIN | EPOLLRDNORM;

	spin_unlock_irqrestore(&dst_q->done_lock, flags);