V4L/DVB (8772): cx18: Convert cx18_queue buffers member to atomic_t

cx18: Convert cx18_queue buffers member to atomic_t.  This allows safe
concurrent access to check if a queue has data without having to acquire the
queue spinlock.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/media/video/cx18/cx18-queue.c b/drivers/media/video/cx18/cx18-queue.c
index 4f3bd43ba802..a33ba04a2686 100644
--- a/drivers/media/video/cx18/cx18-queue.c
+++ b/drivers/media/video/cx18/cx18-queue.c
@@ -37,7 +37,7 @@ void cx18_buf_swap(struct cx18_buffer *buf)
 void cx18_queue_init(struct cx18_queue *q)
 {
         INIT_LIST_HEAD(&q->list);
-        q->buffers = 0;
+        atomic_set(&q->buffers, 0);
         q->bytesused = 0;
 }
 
@@ -54,7 +54,7 @@ void cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
         }
         spin_lock_irqsave(&s->qlock, flags);
         list_add_tail(&buf->list, &q->list);
-        q->buffers++;
+        atomic_inc(&q->buffers);
         q->bytesused += buf->bytesused - buf->readpos;
         spin_unlock_irqrestore(&s->qlock, flags);
 }
@@ -68,7 +68,7 @@ struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
         if (!list_empty(&q->list)) {
                 buf = list_entry(q->list.next, struct cx18_buffer, list);
                 list_del_init(q->list.next);
-                q->buffers--;
+                atomic_dec(&q->buffers);
                 q->bytesused -= buf->bytesused - buf->readpos;
         }
         spin_unlock_irqrestore(&s->qlock, flags);
@@ -92,8 +92,8 @@ struct cx18_buffer *cx18_queue_get_buf_irq(struct cx18_stream *s, u32 id,
                 /* the transport buffers are handled differently,
                    they are not moved to the full queue */
                 if (s->type != CX18_ENC_STREAM_TYPE_TS) {
-                        s->q_free.buffers--;
-                        s->q_full.buffers++;
+                        atomic_dec(&s->q_free.buffers);
+                        atomic_inc(&s->q_full.buffers);
                         s->q_full.bytesused += buf->bytesused;
                         list_move_tail(&buf->list, &s->q_full.list);
                 }
@@ -119,7 +119,7 @@ static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
                 buf = list_entry(q->list.next, struct cx18_buffer, list);
                 list_move_tail(q->list.next, &s->q_free.list);
                 buf->bytesused = buf->readpos = buf->b_flags = 0;
-                s->q_free.buffers++;
+                atomic_inc(&s->q_free.buffers);
         }
         cx18_queue_init(q);
         spin_unlock_irqrestore(&s->qlock, flags);