Re: [PATCH V2] poll method lose race condition

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hi Mauro,

 is it ok for this v2?

Best Regards,
Figo.zhang

> 2009/6/1 Figo.zhang <figo1802@xxxxxxxxx>
>          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@xxxxxxxxx>
>         ---
>          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)
>         
>         
> 

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