On Fri, Jan 06, 2012 at 05:59:29PM -0800, Daniel Walker wrote:

quoted

diff --git a/drivers/dma/msm-dma.c b/drivers/dma/msm-dma.c
new file mode 100644
index 0000000..51d9a2b
--- /dev/null
+++ b/drivers/dma/msm-dma.c

...
+static void msm_chan_desc_cleanup(struct msm_dma_chan *chan)
+{
+	struct msm_dma_desc_sw *desc, *_desc;
+	unsigned long flags;
+
+	dev_dbg(chan->dev, "Cleaning completed descriptor of channel %d\n",
+							chan->chan_id);
+	spin_lock_irqsave(&chan->lock, flags);
+
+	list_for_each_entry_safe(desc, _desc, &chan->active_list, node) {
+		dma_async_tx_callback callback;
+		void *callback_param;
+
+		if (msm_dma_desc_status(chan, desc) == DMA_IN_PROGRESS)
+			break;
+
+		/* Remove from the list of running transactions */
+		list_del(&desc->node);
+
+		/* Run the link descriptor callback function */
+		callback = desc->async_tx.callback;
+		callback_param = desc->async_tx.callback_param;
+		if (callback) {
+			spin_unlock_irqrestore(&chan->lock, flags);
+			callback(callback_param);

Are you sure unlocking here is safe? at_hdmac.c holds the lock the
entire time, and fsldma.c deletes the entire list, then runs the
operations.

Good catch.

According to a comment in at_hdmac.c, it is safe to hold the lock
while calling the callbacks, so that's probably the easiest solution.
I suspect that you've got something in another driver expecting the
lock to be released, and that might have to be changed.

I do think the way fsldma.c does it is cleaner, though, since it
allows the lock to be released for longer periods of times.

In either case, it can't be releasing a lock in the middle of a loop
like this.

David

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
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