upstream: [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>

diff --git a/drivers/media/platform/arv.c b/drivers/media/platform/arv.c
index e346d32..e9410e4 100644 (file)
--- 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;