From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kolorific.com ([61.63.28.39]:34876 "EHLO mail.kolorific.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751403AbZESCOu (ORCPT ); Mon, 18 May 2009 22:14:50 -0400 Subject: [PATCH v2]saa7134-video.c: poll method lose race condition for capture video From: "figo.zhang" To: Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, figo1802@126.com, kraxel@bytesex.org, Hans Verkuil , =?UTF-8?Q?Old=C5=99ich_Jedli=C4=8Dka?= Content-Type: text/plain Date: Tue, 19 May 2009 10:14:30 +0800 Message-Id: <1242699272.3436.6.camel@myhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: 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 --- 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);