Multiple calls to atc_issue_pending() could result in a premature completion of a descriptor from the atchan->active list, as the method always completed the first active descriptor from the list. Instead, issue_pending() should just take the first transaction descriptor from the pending queue, move it to active_list and start the transfer.
Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin peda@axentia.se Signed-off-by: Tudor Ambarus tudor.ambarus@microchip.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se... --- drivers/dma/at_hdmac.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index e9d0c3632868..cb5522417db6 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -1527,16 +1527,26 @@ atc_tx_status(struct dma_chan *chan, }
/** - * atc_issue_pending - try to finish work + * atc_issue_pending - takes the first transaction descriptor in the pending + * queue and starts the transfer. * @chan: target DMA channel */ static void atc_issue_pending(struct dma_chan *chan) { - struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_desc *desc; + unsigned long flags;
dev_vdbg(chan2dev(chan), "issue_pending\n");
- atc_advance_work(atchan); + spin_lock_irqsave(&atchan->lock, flags); + if (atc_chan_is_enabled(atchan) || list_empty(&atchan->queue)) + return spin_unlock_irqrestore(&atchan->lock, flags); + + desc = atc_first_queued(atchan); + list_move_tail(&desc->desc_node, &atchan->active_list); + atc_dostart(atchan, desc); + spin_unlock_irqrestore(&atchan->lock, flags); }
/**