linux-kernel - [PATCH 02/10] dmaengine: at_hdmac: Drop locking in at_hdmac_alloc_chan

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Message-ID: <20200123140237.125799-2-tudor.ambarus@microchip.com>
Date:   Thu, 23 Jan 2020 14:03:04 +0000
From:   <Tudor.Ambarus@...rochip.com>
To:     <Ludovic.Desroches@...rochip.com>, <dan.j.williams@...el.com>,
        <vkoul@...nel.org>
CC:     <dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <Tudor.Ambarus@...rochip.com>
Subject: [PATCH 02/10] dmaengine: at_hdmac: Drop locking in
 at_hdmac_alloc_chan_resources()

From: Tudor Ambarus <tudor.ambarus@...rochip.com>

There is no need for locking in device_alloc_chan_resources(),
the DMA core takes care of it by using a dma_list_mutex around
the DMA devices.

Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
---
 drivers/dma/at_hdmac.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index cad6dcd9cfb5..301bae45cf8d 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1542,10 +1542,8 @@ static int atc_alloc_chan_resources(struct dma_chan *chan)
 	struct at_dma		*atdma = to_at_dma(chan->device);
 	struct at_desc		*desc;
 	struct at_dma_slave	*atslave;
-	unsigned long		flags;
 	int			i;
 	u32			cfg;
-	LIST_HEAD(tmp_list);
 
 	dev_vdbg(chan2dev(chan), "alloc_chan_resources\n");
 
@@ -1583,14 +1581,11 @@ static int atc_alloc_chan_resources(struct dma_chan *chan)
 				"Only %d initial descriptors\n", i);
 			break;
 		}
-		list_add_tail(&desc->desc_node, &tmp_list);
+		list_add_tail(&desc->desc_node, &atchan->free_list);
 	}
 
-	spin_lock_irqsave(&atchan->lock, flags);
 	atchan->descs_allocated = i;
-	list_splice(&tmp_list, &atchan->free_list);
 	dma_cookie_init(chan);
-	spin_unlock_irqrestore(&atchan->lock, flags);
 
 	/* channel parameters */
 	channel_writel(atchan, CFG, cfg);
-- 
2.23.0