Commit 59861547 authored Nov 12, 2018 by Bin Liu Committed by Vinod Koul Dec 05, 2018

dmaengine: cppi41: delete channel from pending list when stop channel



The driver defines three states for a cppi channel.
- idle: .chan_busy == 0 && not in .pending list
- pending: .chan_busy == 0 && in .pending list
- busy: .chan_busy == 1 && not in .pending list

There are cases in which the cppi channel could be in the pending state
when cppi41_dma_issue_pending() is called after cppi41_runtime_suspend()
is called.

cppi41_stop_chan() has a bug for these cases to set channels to idle state.
It only checks the .chan_busy flag, but not the .pending list, then later
when cppi41_runtime_resume() is called the channels in .pending list will
be transitioned to busy state.

Removing channels from the .pending list solves the problem.

Fixes: 975faaeb ("dma: cppi41: start tear down only if channel is busy")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Bin Liu <b-liu@ti.com>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

parent 64068853

drivers/dma/ti/cppi41.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -723,8 +723,22 @@ static int cppi41_stop_chan(struct dma_chan *chan)

		desc_phys = lower_32_bits(c->desc_phys);
		desc_num = (desc_phys - cdd->descs_phys) / sizeof(struct cppi41_desc);
		if (!cdd->chan_busy[desc_num])
		if (!cdd->chan_busy[desc_num]) {
		struct cppi41_channel cc, _ct;

		/*
		* channels might still be in the pendling list if
		* cppi41_dma_issue_pending() is called after
		* cppi41_runtime_suspend() is called
		*/
		list_for_each_entry_safe(cc, _ct, &cdd->pending, node) {
		if (cc != c)
		continue;
		list_del(&cc->node);
		break;
		}
		return 0;
		}

		ret = cppi41_tear_down_chan(c);
		if (ret)

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