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[media] arv: fix sleep_on race 

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 <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Arnd Bergmann 2014-02-26 08:01:48 -03:00 committed by Mauro Carvalho Chehab
parent 111eeaa73a
commit f97881fe50
1 changed files with 3 additions and 3 deletions
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6
drivers/media/platform/arv.c
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@ -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;