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media: v4l2-mem2mem: simplify poll logic

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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: Alexandre Courbot <gnurou@gmail.com>
Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Alexandre Courbot 2020-08-27 14:49:46 +02:00 committed by Mauro Carvalho Chehab
parent 566463afdb
commit 1698a7f151
1 changed files with 5 additions and 21 deletions
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26
drivers/media/v4l2-core/v4l2-mem2mem.c
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@ -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);