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FAILED: patch "[PATCH] dmaengine: at_hdmac: Fix descriptor handling when issuing it" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Nov 14, 2022

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Stable branch dmaengine Microchip AT91 DMA drivers
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The patch below does not apply to the 5.4-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:

ba2423633ba6 ("dmaengine: at_hdmac: Fix descriptor handling when issuing it to hardware") c6babed879fb ("dmaengine: at_hdmac: Fix concurrency problems by removing atc_complete_all()") 078a6506141a ("dmaengine: at_hdmac: Fix deadlocks")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ba2423633ba646e1df20e30cb3cf35495c16f173 Mon Sep 17 00:00:00 2001
From: Tudor Ambarus <[email protected]>
Date: Tue, 25 Oct 2022 12:02:45 +0300
Subject: [PATCH] dmaengine: at_hdmac: Fix descriptor handling when issuing it
to hardware

As it was before, the descriptor was issued to the hardware without adding it to the active (issued) list. This could result in a completion of other descriptor, or/and in the descriptor never being completed.

Fixes dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller")
Reported-by Peter Rosin <[email protected]>
Signed-off-by Tudor Ambarus <[email protected]>
Cc [email protected]
Link https://lore.kernel.org/lkml/[email protected]/ open here
Acked-by Nicolas Ferre <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Vinod Koul <[email protected]>
drivers/dma/at_hdmac.c +11 -4
index b53a9fc15dd9..9e5a30396c1c 100644
@@ -510,8 +510,11 @@ static void atc_advance_work(struct at_dma_chan *atchan)
 
 	/* advance work */
 	spin_lock_irqsave(&atchan->lock, flags);
-	if (!list_empty(&atchan->active_list))
-		atc_dostart(atchan, atc_first_active(atchan));
+	if (!list_empty(&atchan->active_list)) {
+		desc = atc_first_queued(atchan);
+		list_move_tail(&desc->desc_node, &atchan->active_list);
+		atc_dostart(atchan, desc);
+	}
 	spin_unlock_irqrestore(&atchan->lock, flags);
 }
 

@@ -523,6 +526,7 @@ static void atc_advance_work(struct at_dma_chan *atchan)
 static void atc_handle_error(struct at_dma_chan *atchan)
 {
 	struct at_desc *bad_desc;
+	struct at_desc *desc;
 	struct at_desc *child;
 	unsigned long flags;
 

@@ -540,8 +544,11 @@ static void atc_handle_error(struct at_dma_chan *atchan)
 	list_splice_init(&atchan->queue, atchan->active_list.prev);
 
 	/* Try to restart the controller */
-	if (!list_empty(&atchan->active_list))
-		atc_dostart(atchan, atc_first_active(atchan));
+	if (!list_empty(&atchan->active_list)) {
+		desc = atc_first_queued(atchan);
+		list_move_tail(&desc->desc_node, &atchan->active_list);
+		atc_dostart(atchan, desc);
+	}
 
 	/*
 	 * KERN_CRITICAL may seem harsh, but since this only happens