diff --git a/drivers/media/video/videobuf-core.c b/drivers/media/video/videobuf-core.c index 1ba3aaa29dd0..3ab556093ca7 100644 --- a/drivers/media/video/videobuf-core.c +++ b/drivers/media/video/videobuf-core.c @@ -141,6 +141,7 @@ void videobuf_queue_core_init(struct videobuf_queue *q, BUG_ON(!q->int_ops); mutex_init(&q->vb_lock); + init_waitqueue_head(&q->wait); INIT_LIST_HEAD(&q->stream); } @@ -188,6 +189,10 @@ void videobuf_queue_cancel(struct videobuf_queue *q) unsigned long flags = 0; int i; + q->streaming = 0; + q->reading = 0; + wake_up_interruptible_sync(&q->wait); + /* remove queued buffers from list */ if (q->irqlock) spin_lock_irqsave(q->irqlock, flags); @@ -565,6 +570,7 @@ int videobuf_qbuf(struct videobuf_queue *q, } dprintk(1, "qbuf: succeded\n"); retval = 0; + wake_up_interruptible_sync(&q->wait); done: mutex_unlock(&q->vb_lock); @@ -575,37 +581,88 @@ int videobuf_qbuf(struct videobuf_queue *q, return retval; } + +/* Locking: Caller holds q->vb_lock */ +static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock) +{ + int retval; + +checks: + if (!q->streaming) { + dprintk(1, "next_buffer: Not streaming\n"); + retval = -EINVAL; + goto done; + } + + if (list_empty(&q->stream)) { + if (noblock) { + retval = -EAGAIN; + dprintk(2, "next_buffer: no buffers to dequeue\n"); + goto done; + } else { + dprintk(2, "next_buffer: waiting on buffer\n"); + + /* Drop lock to avoid deadlock with qbuf */ + mutex_unlock(&q->vb_lock); + + /* Checking list_empty and streaming is safe without + * locks because we goto checks to validate while + * holding locks before proceeding */ + retval = wait_event_interruptible(q->wait, + !list_empty(&q->stream) || !q->streaming); + mutex_lock(&q->vb_lock); + + if (retval) + goto done; + + goto checks; + } + } + + retval = 0; + +done: + return retval; +} + + +/* Locking: Caller holds q->vb_lock */ +static int stream_next_buffer(struct videobuf_queue *q, + struct videobuf_buffer **vb, int nonblocking) +{ + int retval; + struct videobuf_buffer *buf = NULL; + + retval = stream_next_buffer_check_queue(q, nonblocking); + if (retval) + goto done; + + buf = list_entry(q->stream.next, struct videobuf_buffer, stream); + retval = videobuf_waiton(buf, nonblocking, 1); + if (retval < 0) + goto done; + + *vb = buf; +done: + return retval; +} + int videobuf_dqbuf(struct videobuf_queue *q, struct v4l2_buffer *b, int nonblocking) { - struct videobuf_buffer *buf; + struct videobuf_buffer *buf = NULL; int retval; MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS); mutex_lock(&q->vb_lock); - retval = -EBUSY; - if (q->reading) { - dprintk(1, "dqbuf: Reading running...\n"); - goto done; - } - retval = -EINVAL; - if (b->type != q->type) { - dprintk(1, "dqbuf: Wrong type.\n"); - goto done; - } - if (list_empty(&q->stream)) { - dprintk(1, "dqbuf: stream running\n"); - goto done; - } - buf = list_entry(q->stream.next, struct videobuf_buffer, stream); - mutex_unlock(&q->vb_lock); - retval = videobuf_waiton(buf, nonblocking, 1); - mutex_lock(&q->vb_lock); + + retval = stream_next_buffer(q, &buf, nonblocking); if (retval < 0) { - dprintk(1, "dqbuf: waiton returned %d\n", retval); + dprintk(1, "dqbuf: next_buffer error: %i\n", retval); goto done; } + switch (buf->state) { case VIDEOBUF_ERROR: dprintk(1, "dqbuf: state is error\n"); @@ -654,6 +711,7 @@ int videobuf_streamon(struct videobuf_queue *q) if (q->irqlock) spin_unlock_irqrestore(q->irqlock, flags); + wake_up_interruptible_sync(&q->wait); done: mutex_unlock(&q->vb_lock); return retval; @@ -666,7 +724,6 @@ static int __videobuf_streamoff(struct videobuf_queue *q) return -EINVAL; videobuf_queue_cancel(q); - q->streaming = 0; return 0; } @@ -869,7 +926,6 @@ static void __videobuf_read_stop(struct videobuf_queue *q) q->bufs[i] = NULL; } q->read_buf = NULL; - q->reading = 0; } diff --git a/include/media/videobuf-core.h b/include/media/videobuf-core.h index fcdffdd63304..377a6c6e931b 100644 --- a/include/media/videobuf-core.h +++ b/include/media/videobuf-core.h @@ -153,6 +153,8 @@ struct videobuf_queue { spinlock_t *irqlock; struct device *dev; + wait_queue_head_t wait; /* wait if queue is empty */ + enum v4l2_buf_type type; unsigned int inputs; /* for V4L2_BUF_FLAG_INPUT */ unsigned int msize;