From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752465AbaBZLIf (ORCPT ); Wed, 26 Feb 2014 06:08:35 -0500 Received: from moutng.kundenserver.de ([212.227.126.130]:62692 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751497AbaBZLCn (ORCPT ); Wed, 26 Feb 2014 06:02:43 -0500 From: Arnd Bergmann To: linux-kernel@vger.kernel.org Cc: Arnd Bergmann , Mauro Carvalho Chehab , linux-media@vger.kernel.org Subject: [PATCH 08/16] [media] arv: fix sleep_on race Date: Wed, 26 Feb 2014 12:01:48 +0100 Message-Id: <1393412516-3762435-9-git-send-email-arnd@arndb.de> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1393412516-3762435-1-git-send-email-arnd@arndb.de> References: <1393412516-3762435-1-git-send-email-arnd@arndb.de> X-Provags-ID: V02:K0:U70/+C0uOX6kp8Z2qf+pTDXwAOnX8B5LFC/qEIUkqmQ 0VsHFg78gNY6q4OOwFLbiLZjUqk4Rk8XrJH1DdYYzxDJWphOjN 7An/eLrPao+yHDneHT49+PQzZwlsCIKgeWsz7UCsTvuzCBj2Gn duNLFfWVvMrJbSAp3hek0ii7SpsHlhXOKOW1yV0NtC4Bv7RZH2 uqZkHr2RpYAlN1m8Zb1f2nPXQK7GE3i+J9+mwS0vGXQIdaQuZh amyB9ORZrE+xqrKsm/J87/RjLOevbsNyx8kNfs7HMR5hzy9kJm S8/hXaxYm60dqzpzI4p26b/zmIhNOVD+xLy1ocZiUug7weWwzJ NZF/JlJPRK8jvI9DnAr+xKjQSqY/ac3ciOcO19q1O Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org interruptible_sleep_on is racy and going away. In the arv driver that race has probably never caused problems since it would require a whole video frame to be captured before the read function has a chance to go to sleep, but using wait_event_interruptible lets us kill off the old interface. In order to do this, we have to slightly adapt the meaning of the ar->start_capture field to distinguish between not having started a frame and having completed it. Signed-off-by: Arnd Bergmann Cc: Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org --- drivers/media/platform/arv.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/media/platform/arv.c b/drivers/media/platform/arv.c index e346d32d..e9410e4 100644 --- a/drivers/media/platform/arv.c +++ b/drivers/media/platform/arv.c @@ -109,7 +109,7 @@ extern struct cpuinfo_m32r boot_cpu_data; struct ar { struct v4l2_device v4l2_dev; struct video_device vdev; - unsigned int start_capture; /* duaring capture in INT. mode. */ + int start_capture; /* duaring capture in INT. mode. */ #if USE_INT unsigned char *line_buff; /* DMA line buffer */ #endif @@ -307,11 +307,11 @@ static ssize_t ar_read(struct file *file, char *buf, size_t count, loff_t *ppos) /* * Okay, kick AR LSI to invoke an interrupt */ - ar->start_capture = 0; + ar->start_capture = -1; ar_outl(arvcr1 | ARVCR1_HIEN, ARVCR1); local_irq_restore(flags); /* .... AR interrupts .... */ - interruptible_sleep_on(&ar->wait); + wait_event_interruptible(ar->wait, ar->start_capture == 0); if (signal_pending(current)) { printk(KERN_ERR "arv: interrupted while get frame data.\n"); ret = -EINTR; -- 1.8.3.2