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V4L/DVB (7562): videobuf: Require spinlocks for all videobuf users 

A spinlock is necessary for queue_cancel to work with every driver in the tree.
Otherwise a race exists between IRQ handlers removing buffers from the queue
and queue_cancel invalidating the queue.

Signed-off-by: Brandon Philips <bphilips@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Brandon Philips 2008-03-28 10:18:33 -07:00 committed by Mauro Carvalho Chehab
parent aa9479ed50
commit 0cf4daee31
1 changed files with 18 additions and 28 deletions
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46
drivers/media/video/videobuf-core.c
View File

@ -123,6 +123,9 @@ void videobuf_queue_core_init(struct videobuf_queue *q,
BUG_ON(!q->ops->buf_queue);
BUG_ON(!q->ops->buf_release);
/* Lock is mandatory for queue_cancel to work */
BUG_ON(!irqlock);
/* Having implementations for abstract methods are mandatory */
BUG_ON(!q->int_ops);
@ -180,8 +183,7 @@ void videobuf_queue_cancel(struct videobuf_queue *q)
wake_up_interruptible_sync(&q->wait);
/* remove queued buffers from list */
if (q->irqlock)
spin_lock_irqsave(q->irqlock, flags);
spin_lock_irqsave(q->irqlock, flags);
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (NULL == q->bufs[i])
continue;
@ -191,8 +193,7 @@ void videobuf_queue_cancel(struct videobuf_queue *q)
wake_up_all(&q->bufs[i]->done);
}
}
if (q->irqlock)
spin_unlock_irqrestore(q->irqlock, flags);
spin_unlock_irqrestore(q->irqlock, flags);
/* free all buffers + clear queue */
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
@ -548,11 +549,9 @@ int videobuf_qbuf(struct videobuf_queue *q,
list_add_tail(&buf->stream, &q->stream);
if (q->streaming) {
if (q->irqlock)
spin_lock_irqsave(q->irqlock, flags);
spin_lock_irqsave(q->irqlock, flags);
q->ops->buf_queue(q, buf);
if (q->irqlock)
spin_unlock_irqrestore(q->irqlock, flags);
spin_unlock_irqrestore(q->irqlock, flags);
}
dprintk(1, "qbuf: succeded\n");
retval = 0;
@ -689,13 +688,11 @@ int videobuf_streamon(struct videobuf_queue *q)
if (q->streaming)
goto done;
q->streaming = 1;
if (q->irqlock)
spin_lock_irqsave(q->irqlock, flags);
spin_lock_irqsave(q->irqlock, flags);
list_for_each_entry(buf, &q->stream, stream)
if (buf->state == VIDEOBUF_PREPARED)
q->ops->buf_queue(q, buf);
if (q->irqlock)
spin_unlock_irqrestore(q->irqlock, flags);
spin_unlock_irqrestore(q->irqlock, flags);
wake_up_interruptible_sync(&q->wait);
done:
@ -751,11 +748,9 @@ static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
goto done;
/* start capture & wait */
if (q->irqlock)
spin_lock_irqsave(q->irqlock, flags);
spin_lock_irqsave(q->irqlock, flags);
q->ops->buf_queue(q, q->read_buf);
if (q->irqlock)
spin_unlock_irqrestore(q->irqlock, flags);
spin_unlock_irqrestore(q->irqlock, flags);
retval = videobuf_waiton(q->read_buf, 0, 0);
if (0 == retval) {
CALL(q, sync, q, q->read_buf);
@ -816,12 +811,11 @@ ssize_t videobuf_read_one(struct videobuf_queue *q,
q->read_buf = NULL;
goto done;
}
if (q->irqlock)
spin_lock_irqsave(q->irqlock, flags);
spin_lock_irqsave(q->irqlock, flags);
q->ops->buf_queue(q, q->read_buf);
if (q->irqlock)
spin_unlock_irqrestore(q->irqlock, flags);
spin_unlock_irqrestore(q->irqlock, flags);
q->read_off = 0;
}
@ -887,12 +881,10 @@ static int __videobuf_read_start(struct videobuf_queue *q)
return err;
list_add_tail(&q->bufs[i]->stream, &q->stream);
}
if (q->irqlock)
spin_lock_irqsave(q->irqlock, flags);
spin_lock_irqsave(q->irqlock, flags);
for (i = 0; i < count; i++)
q->ops->buf_queue(q, q->bufs[i]);
if (q->irqlock)
spin_unlock_irqrestore(q->irqlock, flags);
spin_unlock_irqrestore(q->irqlock, flags);
q->reading = 1;
return 0;
}
@ -1004,11 +996,9 @@ ssize_t videobuf_read_stream(struct videobuf_queue *q,
if (q->read_off == q->read_buf->size) {
list_add_tail(&q->read_buf->stream,
&q->stream);
if (q->irqlock)
spin_lock_irqsave(q->irqlock, flags);
spin_lock_irqsave(q->irqlock, flags);
q->ops->buf_queue(q, q->read_buf);
if (q->irqlock)
spin_unlock_irqrestore(q->irqlock, flags);
spin_unlock_irqrestore(q->irqlock, flags);
q->read_buf = NULL;
}
if (retval < 0)