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>

1 files changed, 41 insertions, 32 deletions

diff --git a/drivers/media/video/vivi.c b/drivers/media/video/vivi.c
index 004209d54498..c9d23633fe42 100644
--- 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();
 }