linux-kernel - [PATCH v2 12/32] dmaengine: at_hdmac: Fix completion of unissued descriptor in case of errors

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Message-ID: <20221025090306.297886-13-tudor.ambarus@microchip.com>
Date:   Tue, 25 Oct 2022 12:02:46 +0300
From:   Tudor Ambarus <tudor.ambarus@...rochip.com>
To:     <vkoul@...nel.org>, <peda@...ntia.se>, <du@...ntia.se>
CC:     <maciej.sosnowski@...el.com>, <nicolas.ferre@...rochip.com>,
        <mripard@...nel.org>, <torfl6749@...il.com>,
        <linux-kernel@...r.kernel.org>, <dmaengine@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        "Tudor Ambarus" <tudor.ambarus@...rochip.com>,
        <stable@...r.kernel.org>
Subject: [PATCH v2 12/32] dmaengine: at_hdmac: Fix completion of unissued descriptor in case of errors

In case the controller detected an error, the code took the chance to move
all the queued (submitted) descriptors to the active (issued) list. This
was wrong as if there were any descriptors in the submitted list they were
moved to the issued list without actually issuing them to the controller,
thus a completion could be raised without even fireing the descriptor.

Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller")
Reported-by: Peter Rosin <peda@...ntia.se>
Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/
---
 drivers/dma/at_hdmac.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 9e5a30396c1c..80eeb4fb88ef 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -539,10 +539,6 @@ static void atc_handle_error(struct at_dma_chan *atchan)
 	bad_desc = atc_first_active(atchan);
 	list_del_init(&bad_desc->desc_node);
 
-	/* As we are stopped, take advantage to push queued descriptors
-	 * in active_list */
-	list_splice_init(&atchan->queue, atchan->active_list.prev);
-
 	/* Try to restart the controller */
 	if (!list_empty(&atchan->active_list)) {
 		desc = atc_first_queued(atchan);
-- 
2.25.1