From: "Figo.zhang" <figo1802@gmail.com>
To: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [PATCH V2] poll method lose race condition
Date: Mon, 15 Jun 2009 21:28:21 +0800 [thread overview]
Message-ID: <1245072502.3312.5.camel@myhost> (raw)
In-Reply-To: <c6ed1ac50906150627x73586853redfd1abbff90dec7@mail.gmail.com>
hi Mauro,
is it ok for this v2?
Best Regards,
Figo.zhang
> 2009/6/1 Figo.zhang <figo1802@gmail.com>
> bttv-driver.c,cx23885-video.c,cx88-video.c: poll method lose
> race condition for capture video.
>
> In v2, use the clear logic.Thanks to Trent Piepho's help.
>
> Signed-off-by: Figo.zhang <figo1802@gmail.com>
> ---
> drivers/media/video/bt8xx/bttv-driver.c | 20
> ++++++++++++--------
> drivers/media/video/cx23885/cx23885-video.c | 15
> +++++++++++----
> drivers/media/video/cx88/cx88-video.c | 15
> +++++++++++----
> 3 files changed, 34 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/media/video/bt8xx/bttv-driver.c
> b/drivers/media/video/bt8xx/bttv-driver.c
> index 23b7499..8d20528 100644
> --- a/drivers/media/video/bt8xx/bttv-driver.c
> +++ b/drivers/media/video/bt8xx/bttv-driver.c
> @@ -3152,6 +3152,7 @@ static unsigned int bttv_poll(struct
> file *file, poll_table *wait)
> struct bttv_fh *fh = file->private_data;
> struct bttv_buffer *buf;
> enum v4l2_field field;
> + unsigned int rc = POLLERR;
>
> if (V4L2_BUF_TYPE_VBI_CAPTURE == fh->type) {
> if (!
> check_alloc_btres(fh->btv,fh,RESOURCE_VBI))
> @@ -3160,9 +3161,10 @@ static unsigned int bttv_poll(struct
> file *file, poll_table *wait)
> }
>
> if (check_btres(fh,RESOURCE_VIDEO_STREAM)) {
> + mutex_lock(&fh->cap.vb_lock);
> /* streaming capture */
> if (list_empty(&fh->cap.stream))
> - return POLLERR;
> + return done;
> buf = list_entry(fh->cap.stream.next,struct
> bttv_buffer,vb.stream);
> } else {
> /* read() capture */
> @@ -3170,16 +3172,16 @@ static unsigned int bttv_poll(struct
> file *file, poll_table *wait)
> if (NULL == fh->cap.read_buf) {
> /* need to capture a new frame */
> if
> (locked_btres(fh->btv,RESOURCE_VIDEO_STREAM))
> - goto err;
> + goto done;
> fh->cap.read_buf =
> videobuf_sg_alloc(fh->cap.msize);
> if (NULL == fh->cap.read_buf)
> - goto err;
> + goto done;
> fh->cap.read_buf->memory =
> V4L2_MEMORY_USERPTR;
> field = videobuf_next_field(&fh->cap);
> if (0 !=
> fh->cap.ops->buf_prepare(&fh->cap,fh->cap.read_buf,field)) {
> kfree (fh->cap.read_buf);
> fh->cap.read_buf = NULL;
> - goto err;
> + goto done;
> }
>
> fh->cap.ops->buf_queue(&fh->cap,fh->cap.read_buf);
> fh->cap.read_off = 0;
> @@ -3191,11 +3193,13 @@ static unsigned int bttv_poll(struct
> file *file, poll_table *wait)
> poll_wait(file, &buf->vb.done, wait);
> if (buf->vb.state == VIDEOBUF_DONE ||
> buf->vb.state == VIDEOBUF_ERROR)
> - return POLLIN|POLLRDNORM;
> - return 0;
> -err:
> + rc = POLLIN|POLLRDNORM;
> + else
> + rc = 0;
> +
> +done:
> mutex_unlock(&fh->cap.vb_lock);
> - return POLLERR;
> + return rc;
> }
>
> static int bttv_open(struct file *file)
> diff --git a/drivers/media/video/cx23885/cx23885-video.c
> b/drivers/media/video/cx23885/cx23885-video.c
> index 68068c6..f542493 100644
> --- a/drivers/media/video/cx23885/cx23885-video.c
> +++ b/drivers/media/video/cx23885/cx23885-video.c
> @@ -796,6 +796,7 @@ static unsigned int video_poll(struct file
> *file,
> {
> struct cx23885_fh *fh = file->private_data;
> struct cx23885_buffer *buf;
> + unsigned int rc = POLLERR;
>
> if (V4L2_BUF_TYPE_VBI_CAPTURE == fh->type) {
> if (!res_get(fh->dev, fh, RESOURCE_VBI))
> @@ -803,23 +804,29 @@ static unsigned int video_poll(struct
> file *file,
> return videobuf_poll_stream(file, &fh->vbiq,
> wait);
> }
>
> + mutex_lock(&fh->vidq.vb_lock);
> if (res_check(fh, RESOURCE_VIDEO)) {
> /* streaming capture */
> if (list_empty(&fh->vidq.stream))
> - return POLLERR;
> + goto done;
> buf = list_entry(fh->vidq.stream.next,
> struct cx23885_buffer, vb.stream);
> } else {
> /* read() capture */
> buf = (struct cx23885_buffer
> *)fh->vidq.read_buf;
> if (NULL == buf)
> - return POLLERR;
> + goto done;
> }
> poll_wait(file, &buf->vb.done, wait);
> if (buf->vb.state == VIDEOBUF_DONE ||
> buf->vb.state == VIDEOBUF_ERROR)
> - return POLLIN|POLLRDNORM;
> - return 0;
> + rc = POLLIN|POLLRDNORM;
> + else
> + rc = 0;
> +
> +done:
> + mutex_unlock(&fh->vidq.vb_lock);
> + return rc;
> }
>
> static int video_release(struct file *file)
> diff --git a/drivers/media/video/cx88/cx88-video.c
> b/drivers/media/video/cx88/cx88-video.c
> index b993d42..b1ca54b 100644
> --- a/drivers/media/video/cx88/cx88-video.c
> +++ b/drivers/media/video/cx88/cx88-video.c
> @@ -869,6 +869,7 @@ video_poll(struct file *file, struct
> poll_table_struct *wait)
> {
> struct cx8800_fh *fh = file->private_data;
> struct cx88_buffer *buf;
> + unsigned int rc = POLLERR;
>
> if (V4L2_BUF_TYPE_VBI_CAPTURE == fh->type) {
> if (!res_get(fh->dev,fh,RESOURCE_VBI))
> @@ -876,22 +877,28 @@ video_poll(struct file *file, struct
> poll_table_struct *wait)
> return videobuf_poll_stream(file, &fh->vbiq,
> wait);
> }
>
> + mutex_lock(&fh->vidq.vb_lock);
> if (res_check(fh,RESOURCE_VIDEO)) {
> /* streaming capture */
> if (list_empty(&fh->vidq.stream))
> - return POLLERR;
> + goto done;
> buf = list_entry(fh->vidq.stream.next,struct
> cx88_buffer,vb.stream);
> } else {
> /* read() capture */
> buf = (struct cx88_buffer*)fh->vidq.read_buf;
> if (NULL == buf)
> - return POLLERR;
> + goto done;
> }
> poll_wait(file, &buf->vb.done, wait);
> if (buf->vb.state == VIDEOBUF_DONE ||
> buf->vb.state == VIDEOBUF_ERROR)
> - return POLLIN|POLLRDNORM;
> - return 0;
> + rc = POLLIN|POLLRDNORM;
> + else
> + rc = 0;
> +
> +done:
> + mutex_unlock(&fh->vidq.vb_lock);
> + return rc;
> }
>
> static int video_release(struct file *file)
>
>
>
next prev parent reply other threads:[~2009-06-15 13:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-01 2:05 [PATCH V2] poll method lose race condition Figo.zhang
[not found] ` <c6ed1ac50906150627x73586853redfd1abbff90dec7@mail.gmail.com>
2009-06-15 13:28 ` Figo.zhang [this message]
2009-06-16 15:51 ` Mauro Carvalho Chehab
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