V4L/DVB (6817): Cleanup kernel thread and provide overrun detection

The previous code were a little bit messy. Cleans it up.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

diff --git a/drivers/media/video/vivi.c b/drivers/media/video/vivi.c
index 004209d54498827f57310287d3bb849cc1784f2d..c9d23633fe42880a7fd95b94414585ac0024a8a7 100644 (file)
--- a/drivers/media/video/vivi.c
+++ b/drivers/media/video/vivi.c
@@ -425,48 +425,57 @@ static void vivi_thread_tick(struct vivi_dmaqueue  *dma_q)
        spin_unlock(&dev->slock);
 }
 
+#define frames_to_ms(frames)                                   \
+       ((frames * WAKE_NUMERATOR * 1000) / WAKE_DENOMINATOR)
+
 static void vivi_sleep(struct vivi_dmaqueue  *dma_q)
 {
        struct vivi_dev *dev = container_of(dma_q, struct vivi_dev, vidq);
-       int timeout;
+       int timeout, running_time;
        DECLARE_WAITQUEUE(wait, current);
 
        dprintk(dev, 1, "%s dma_q=0x%08lx\n", __FUNCTION__,
                (unsigned long)dma_q);
 
        add_wait_queue(&dma_q->wq, &wait);
-       if (!kthread_should_stop()) {
-               dma_q->frame++;
-
-               /* Calculate time to wake up */
-               timeout = dma_q->ini_jiffies+
-                         msecs_to_jiffies((dma_q->frame*WAKE_NUMERATOR * 1000)
-                                          / WAKE_DENOMINATOR) - jiffies;
-
-               if (timeout <= 0) {
-                       int old = dma_q->frame;
-                       dma_q->frame = (jiffies_to_msecs(jiffies -
-                                       dma_q->ini_jiffies) *
-                                       WAKE_DENOMINATOR) /
-                                       (WAKE_NUMERATOR * 1000) + 1;
-
-                       timeout = dma_q->ini_jiffies+
-                               msecs_to_jiffies((dma_q->frame *
-                                                 WAKE_NUMERATOR * 1000)
-                                                 / WAKE_DENOMINATOR) - jiffies;
-
-                       dprintk(dev, 1, "underrun, losed %d frames. "
-                                  "Now, frame is %d. Waking on %d jiffies\n",
-                                  dma_q->frame-old, dma_q->frame, timeout);
-               } else
-                       dprintk(dev, 1, "will sleep for %i jiffies\n",
-                               timeout);
-
-               vivi_thread_tick(dma_q);
-
-               schedule_timeout_interruptible(timeout);
-       }
+       if (kthread_should_stop())
+               goto stop_task;
+
+       running_time = jiffies - dma_q->ini_jiffies;
+       dma_q->frame++;
+
+       /* Calculate time to wake up */
+       timeout = msecs_to_jiffies(frames_to_ms(dma_q->frame)) - running_time;
+
+       if (timeout > msecs_to_jiffies(frames_to_ms(2)) || timeout <= 0) {
+               int old = dma_q->frame;
+               int nframes;
+
+               dma_q->frame = (jiffies_to_msecs(running_time) /
+                              frames_to_ms(1)) + 1;
+
+               timeout = msecs_to_jiffies(frames_to_ms(dma_q->frame))
+                         - running_time;
+
+               if (unlikely (timeout <= 0))
+                       timeout = 1;
+
+               nframes = (dma_q->frame > old)?
+                                 dma_q->frame - old : old - dma_q->frame;
+
+               dprintk(dev, 1, "%ld: %s %d frames. "
+                       "Current frame is %d. Will sleep for %d jiffies\n",
+                       jiffies,
+                       (dma_q->frame > old)? "Underrun, losed" : "Overrun of",
+                       nframes, dma_q->frame, timeout);
+       } else
+               dprintk(dev, 1, "will sleep for %d jiffies\n", timeout);
+
+       vivi_thread_tick(dma_q);
+
+       schedule_timeout_interruptible(timeout);
 
+stop_task:
        remove_wait_queue(&dma_q->wq, &wait);
        try_to_freeze();
 }