saa7134-video.c: poll method lose race condition for capture video.
In v2, when buf == NULL, it will goto err, return "PULLERR"
immediately.
Signed-off-by: Figo.zhang <figo.zhang@xxxxxxxxxxxxx>
---
drivers/media/video/saa7134/saa7134-video.c | 9 ++++++---
1 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/media/video/saa7134/saa7134-video.c b/drivers/media/video/saa7134/saa7134-video.c
index 493cad9..b1c2dbd 100644
--- a/drivers/media/video/saa7134/saa7134-video.c
+++ b/drivers/media/video/saa7134/saa7134-video.c
@@ -1423,11 +1423,13 @@ video_poll(struct file *file, struct poll_table_struct *wait)
{
struct saa7134_fh *fh = file->private_data;
struct videobuf_buffer *buf = NULL;
+ unsigned int rc = 0;
if (V4L2_BUF_TYPE_VBI_CAPTURE == fh->type)
return videobuf_poll_stream(file, &fh->vbi, wait);
if (res_check(fh,RESOURCE_VIDEO)) {
+ mutex_lock(&fh->cap.vb_lock);
if (!list_empty(&fh->cap.stream))
buf = list_entry(fh->cap.stream.next, struct videobuf_buffer, stream);
} else {
@@ -1446,13 +1448,14 @@ video_poll(struct file *file, struct poll_table_struct *wait)
}
if (!buf)
- return POLLERR;
+ goto err;
poll_wait(file, &buf->done, wait);
if (buf->state == VIDEOBUF_DONE ||
buf->state == VIDEOBUF_ERROR)
- return POLLIN|POLLRDNORM;
- return 0;
+ rc = POLLIN|POLLRDNORM;
+ mutex_unlock(&fh->cap.vb_lock);
+ return rc;
err:
mutex_unlock(&fh->cap.vb_lock);
--
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