FAILED: patch "[PATCH] dmaengine: at_hdmac: Fix premature completion of desc in" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-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 <[email protected]>.

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 <[email protected]>
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.

index e9d0c3632868..cb5522417db6 100644
@@ -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);
 }
 
 /**