Commit dd8695e4 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
Browse files

media: v4l2-mem2mem: fix epoll() by calling poll_wait first 



The epoll function expects that whenever the poll file op is
called, the poll_wait function is also called. That didn't
always happen in v4l2_m2m_poll(). Fix this, otherwise
epoll() would timeout when it shouldn't.

Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent 398d7680

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

+7 −12
Original line number Diff line number Diff line
@@ -617,20 +617,22 @@ __poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx, 
	__poll_t rc = 0;

	unsigned long flags;



	src_q = v4l2_m2m_get_src_vq(m2m_ctx);

	dst_q = v4l2_m2m_get_dst_vq(m2m_ctx);



	poll_wait(file, &src_q->done_wq, wait);

	poll_wait(file, &dst_q->done_wq, wait);



	if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {

		struct v4l2_fh *fh = file->private_data;



		poll_wait(file, &fh->wait, wait);

		if (v4l2_event_pending(fh))

			rc = EPOLLPRI;

		else if (req_events & EPOLLPRI)

			poll_wait(file, &fh->wait, wait);

		if (!(req_events & (EPOLLOUT | EPOLLWRNORM | EPOLLIN | EPOLLRDNORM)))

			return rc;

	}



	src_q = v4l2_m2m_get_src_vq(m2m_ctx);

	dst_q = v4l2_m2m_get_dst_vq(m2m_ctx);



	/*

	 * There has to be at least one buffer queued on each queued_list, which

	 * means either in driver already or waiting for driver to claim it
@@ -642,11 +644,6 @@ __poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx, 
		goto end;

	}



	spin_lock_irqsave(&src_q->done_lock, flags);

	if (list_empty(&src_q->done_list))

		poll_wait(file, &src_q->done_wq, wait);

	spin_unlock_irqrestore(&src_q->done_lock, flags);



	spin_lock_irqsave(&dst_q->done_lock, flags);

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

		/*
@@ -657,8 +654,6 @@ __poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx, 
			spin_unlock_irqrestore(&dst_q->done_lock, flags);

			return rc | EPOLLIN | EPOLLRDNORM;

		}



		poll_wait(file, &dst_q->done_wq, wait);

	}

	spin_unlock_irqrestore(&dst_q->done_lock, flags);

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