From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pz0-f177.google.com ([209.85.222.177]:39552 "EHLO mail-pz0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753802AbZFACFY (ORCPT ); Sun, 31 May 2009 22:05:24 -0400 Received: by pzk7 with SMTP id 7so5722133pzk.33 for ; Sun, 31 May 2009 19:05:26 -0700 (PDT) Subject: [PATCH V2] poll method lose race condition From: "Figo.zhang" To: Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, kraxel@bytesex.org, Hans Verkuil , Trent Piepho Content-Type: text/plain Date: Mon, 01 Jun 2009 10:05:04 +0800 Message-Id: <1243821904.3499.5.camel@myhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: 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 --- 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)