4.4-stable review patch. If anyone has any objections, please let me know.
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From: Bin Liu b-liu@ti.com
commit 59861547ec9a9736e7882f6fb0c096a720ff811a upstream.
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: 975faaeb9985 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/dma/cppi41.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
--- a/drivers/dma/cppi41.c +++ b/drivers/dma/cppi41.c @@ -628,8 +628,22 @@ static int cppi41_stop_chan(struct dma_c
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)