The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Possible dependencies:
fcd37565efda ("dmaengine: at_hdmac: Fix premature completion of desc in issue_pending") 8a47221fc284 ("dmaengine: at_hdmac: Start transfer for cyclic channels in issue_pending") 078a6506141a ("dmaengine: at_hdmac: Fix deadlocks")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From fcd37565efdaffeac179d0f0ce980ac79bfdf569 Mon Sep 17 00:00:00 2001 From: Tudor Ambarus tudor.ambarus@microchip.com Date: Tue, 25 Oct 2022 12:02:38 +0300 Subject: [PATCH] dmaengine: at_hdmac: Fix premature completion of desc in issue_pending
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... Acked-by: Nicolas Ferre nicolas.ferre@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.co... Link: https://lore.kernel.org/r/20221025090306.297886-5-tudor.ambarus@microchip.co... Signed-off-by: Vinod Koul vkoul@kernel.org
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); }
/**