V4L/DVB (9800): cx18: Eliminate q_io from stream buffer handling

Eliminate q_io from stream buffer handling in anticipation of upcoming
changes in buffer handling.  q_io was a holdover from ivtv and it's function
in cx18 was trivial and not necessary.  We just push things back onto the
front of q_full now, instead of maintaining a 1 buffer q_io queue.

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

5 files changed, 25 insertions, 15 deletions

diff --git a/drivers/media/video/cx18/cx18-driver.h b/drivers/media/video/cx18/cx18-driver.h
index 94c196a91295..f88d82348293 100644
--- a/drivers/media/video/cx18/cx18-driver.h
+++ b/drivers/media/video/cx18/cx18-driver.h
@@ -290,7 +290,6 @@ struct cx18_stream {
         /* Buffer Queues */
         struct cx18_queue q_free;       /* free buffers */
         struct cx18_queue q_full;       /* full buffers */
-        struct cx18_queue q_io;         /* waiting for I/O */
 
         /* DVB / Digital Transport */
         struct cx18_dvb dvb;
diff --git a/drivers/media/video/cx18/cx18-fileops.c b/drivers/media/video/cx18/cx18-fileops.c
index 2c8117510fb4..504a1f9edec6 100644
--- a/drivers/media/video/cx18/cx18-fileops.c
+++ b/drivers/media/video/cx18/cx18-fileops.c
@@ -195,11 +195,6 @@ static struct cx18_buffer *cx18_get_buffer(struct cx18_stream *s, int non_block,
                                 return buf;
                 }
 
-                /* do we have leftover data? */
-                buf = cx18_dequeue(s, &s->q_io);
-                if (buf)
-                        return buf;
-
                 /* do we have new data? */
                 buf = cx18_dequeue(s, &s->q_full);
                 if (buf) {
@@ -375,7 +370,7 @@ static ssize_t cx18_read(struct cx18_stream *s, char __user *ubuf,
                                           cx->enc_mem,
                                         1, buf->id, s->buf_size);
                         } else
-                                cx18_enqueue(s, buf, &s->q_io);
+                                cx18_push(s, buf, &s->q_full);
                 } else if (buf->readpos == buf->bytesused) {
                         int idx = cx->vbi.inserted_frame % CX18_VBI_FRAMES;
 
@@ -519,7 +514,7 @@ unsigned int cx18_v4l2_enc_poll(struct file *filp, poll_table *wait)
         CX18_DEBUG_HI_FILE("Encoder poll\n");
         poll_wait(filp, &s->waitq, wait);
 
-        if (atomic_read(&s->q_full.buffers) || atomic_read(&s->q_io.buffers))
+        if (atomic_read(&s->q_full.buffers))
                 return POLLIN | POLLRDNORM;
         if (eof)
                 return POLLHUP;
diff --git a/drivers/media/video/cx18/cx18-queue.c b/drivers/media/video/cx18/cx18-queue.c
index 7b09c9a3ee8f..fdfc83ee3d4e 100644
--- a/drivers/media/video/cx18/cx18-queue.c
+++ b/drivers/media/video/cx18/cx18-queue.c
@@ -42,8 +42,8 @@ void cx18_queue_init(struct cx18_queue *q)
         q->bytesused = 0;
 }
 
-void cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
-                struct cx18_queue *q)
+void _cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
+                   struct cx18_queue *q, int to_front)
 {
         /* clear the buffer if it is going to be enqueued to the free queue */
         if (q == &s->q_free) {
@@ -53,7 +53,10 @@ void cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
                 buf->skipped = 0;
         }
         mutex_lock(&s->qlock);
-        list_add_tail(&buf->list, &q->list);
+        if (to_front)
+                list_add(&buf->list, &q->list); /* LIFO */
+        else
+                list_add_tail(&buf->list, &q->list); /* FIFO */
         atomic_inc(&q->buffers);
         q->bytesused += buf->bytesused - buf->readpos;
         mutex_unlock(&s->qlock);
@@ -159,7 +162,6 @@ static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
 
 void cx18_flush_queues(struct cx18_stream *s)
 {
-        cx18_queue_flush(s, &s->q_io);
         cx18_queue_flush(s, &s->q_full);
 }
 
diff --git a/drivers/media/video/cx18/cx18-queue.h b/drivers/media/video/cx18/cx18-queue.h
index ff50a2b7e5bc..d184e55ce624 100644
--- a/drivers/media/video/cx18/cx18-queue.h
+++ b/drivers/media/video/cx18/cx18-queue.h
@@ -43,9 +43,24 @@ static inline void cx18_buf_sync_for_device(struct cx18_stream *s,
 void cx18_buf_swap(struct cx18_buffer *buf);
 
 /* cx18_queue utility functions */
-void cx18_queue_init(struct cx18_queue *q);
+void _cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
+                   struct cx18_queue *q, int to_front);
+
+static inline
 void cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
-        struct cx18_queue *q);
+                  struct cx18_queue *q)
+{
+        _cx18_enqueue(s, buf, q, 0); /* FIFO */
+}
+
+static inline
+void cx18_push(struct cx18_stream *s, struct cx18_buffer *buf,
+               struct cx18_queue *q)
+{
+        _cx18_enqueue(s, buf, q, 1); /* LIFO */
+}
+
+void cx18_queue_init(struct cx18_queue *q);
 struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q);
 struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
         u32 bytesused);
diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c
index 8c8e92b20c7b..a1cf434f7975 100644
--- a/drivers/media/video/cx18/cx18-streams.c
+++ b/drivers/media/video/cx18/cx18-streams.c
@@ -138,7 +138,6 @@ static void cx18_stream_init(struct cx18 *cx, int type)
         s->id = -1;
         cx18_queue_init(&s->q_free);
         cx18_queue_init(&s->q_full);
-        cx18_queue_init(&s->q_io);
 }
 
 static int cx18_prep_dev(struct cx18 *cx, int type)