V4L/DVB (11618): cx18: Convert per stream mutex locks to per queue spin locks
To avoid sleeps in providing buffers to user space and in handling incoming
buffers from the capture unit, converted the per stream mutex for locking
queues to 3 spin locks. There is now a spin lock per queue
to increase concurrency when moving buffers around.
Also simplified queue manipulations and buffer handling of incoming buffers
of data from the capture unit.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c
index bbeb01c..e1934e9 100644
--- a/drivers/media/video/cx18/cx18-streams.c
+++ b/drivers/media/video/cx18/cx18-streams.c
@@ -116,11 +116,13 @@
s->buffers = cx->stream_buffers[type];
s->buf_size = cx->stream_buf_size[type];
- mutex_init(&s->qlock);
init_waitqueue_head(&s->waitq);
s->id = -1;
+ spin_lock_init(&s->q_free.lock);
cx18_queue_init(&s->q_free);
+ spin_lock_init(&s->q_busy.lock);
cx18_queue_init(&s->q_busy);
+ spin_lock_init(&s->q_full.lock);
cx18_queue_init(&s->q_full);
}
@@ -685,13 +687,13 @@
/* Init all the cpu_mdls for this stream */
cx18_flush_queues(s);
- mutex_lock(&s->qlock);
+ spin_lock(&s->q_free.lock);
list_for_each_entry(buf, &s->q_free.list, list) {
cx18_writel(cx, buf->dma_handle,
&cx->scb->cpu_mdl[buf->id].paddr);
cx18_writel(cx, s->buf_size, &cx->scb->cpu_mdl[buf->id].length);
}
- mutex_unlock(&s->qlock);
+ spin_unlock(&s->q_free.lock);
_cx18_stream_load_fw_queue(s);
/* begin_capture */