linux-kernel - [PATCH 15/33] dmaengine: at_hdmac: Free the memset buf without holding the chan lock

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Date:   Sat, 20 Aug 2022 15:56:59 +0300
From:   Tudor Ambarus <tudor.ambarus@...rochip.com>
To:     <vkoul@...nel.org>, <peda@...ntia.se>, <du@...ntia.se>,
        <regressions@...mhuis.info>
CC:     <ludovic.desroches@...rochip.com>, <maciej.sosnowski@...el.com>,
        <tudor.ambarus@...rochip.com>, <dan.j.williams@...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>, <stable@...r.kernel.org>
Subject: [PATCH 15/33] dmaengine: at_hdmac: Free the memset buf without holding the chan lock

There's no need to hold the channel lock when freeing the memset buf, as
the operation has already completed. Free the memset buf without holding
the channel lock.

Fixes: 4d112426c344 ("dmaengine: hdmac: Add memset capabilities")
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 | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index b3184da7ced4..c2b3d7b63920 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -897,13 +897,6 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
 	if (!atc_chan_is_cyclic(atchan))
 		dma_cookie_complete(txd);
 
-	/* If the transfer was a memset, free our temporary buffer */
-	if (desc->memset_buffer) {
-		dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
-			      desc->memset_paddr);
-		desc->memset_buffer = false;
-	}
-
 	/* Remove transfer node from the active list. */
 	list_del_init(&desc->desc_node);
 	spin_unlock_irqrestore(&atchan->lock, flags);
@@ -922,6 +915,13 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
 	/* add myself to free_list */
 	list_add(&desc->desc_node, &atchan->free_list);
 	spin_unlock_irqrestore(&atchan->lock, flags);
+
+	/* If the transfer was a memset, free our temporary buffer */
+	if (desc->memset_buffer) {
+		dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
+			      desc->memset_paddr);
+		desc->memset_buffer = false;
+	}
 }
 
 /**
-- 
2.25.1