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From:   Tudor Ambarus <tudor.ambarus@microchip.com>
To:     <vkoul@kernel.org>, <peda@axentia.se>, <du@axentia.se>,
        <regressions@leemhuis.info>
CC:     <ludovic.desroches@microchip.com>, <maciej.sosnowski@intel.com>,
        <tudor.ambarus@microchip.com>, <dan.j.williams@intel.com>,
        <nicolas.ferre@microchip.com>, <mripard@kernel.org>,
        <torfl6749@gmail.com>, <linux-kernel@vger.kernel.org>,
        <dmaengine@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <stable@vger.kernel.org>
Subject: [PATCH 17/33] dmaengine: at_hdmac: Fix descriptor handling when issuing it to hardware
Date:   Sat, 20 Aug 2022 15:57:01 +0300
Message-ID: <20220820125717.588722-18-tudor.ambarus@microchip.com>
In-Reply-To: <20220820125717.588722-1-tudor.ambarus@microchip.com>
References: <20220820125717.588722-1-tudor.ambarus@microchip.com>
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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 <peda@axentia.se>
Cc: stable@vger.kernel.org
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/
---
 drivers/dma/at_hdmac.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 635c3be74399..e5ac73768d13 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -945,8 +945,11 @@ 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);
 }
 
@@ -958,6 +961,7 @@ 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;
 
@@ -975,8 +979,11 @@ 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
-- 
2.25.1