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From: Tudor Ambarus <tudor.ambarus@microchip.com>
To: <vkoul@kernel.org>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>,
	mripard@kernel.org, linux-kernel@vger.kernel.org,
	ludovic.desroches@microchip.com, dmaengine@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 06/12] dmaengine: at_xdmac: Move the free desc to the tail of the desc list
Date: Wed, 15 Dec 2021 13:01:09 +0200	[thread overview]
Message-ID: <20211215110115.191749-7-tudor.ambarus@microchip.com> (raw)
In-Reply-To: <20211215110115.191749-1-tudor.ambarus@microchip.com>

Move the free desc to the tail of the list, so that the sequence of
descriptors is more track-able in case of debug. One would know which
descriptor should come next and could easier catch concurrency over
descriptors for example. virt-dma uses list_splice_tail_init() as well,
follow the core driver.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
 drivers/dma/at_xdmac.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index d5b37459f906..b6547f1b5645 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -729,7 +729,8 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 		if (!desc) {
 			dev_err(chan2dev(chan), "can't get descriptor\n");
 			if (first)
-				list_splice_init(&first->descs_list, &atchan->free_descs_list);
+				list_splice_tail_init(&first->descs_list,
+						      &atchan->free_descs_list);
 			goto spin_unlock;
 		}
 
@@ -817,7 +818,8 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
 		if (!desc) {
 			dev_err(chan2dev(chan), "can't get descriptor\n");
 			if (first)
-				list_splice_init(&first->descs_list, &atchan->free_descs_list);
+				list_splice_tail_init(&first->descs_list,
+						      &atchan->free_descs_list);
 			spin_unlock_irqrestore(&atchan->lock, irqflags);
 			return NULL;
 		}
@@ -1051,8 +1053,8 @@ at_xdmac_prep_interleaved(struct dma_chan *chan,
 							       src_addr, dst_addr,
 							       xt, chunk);
 			if (!desc) {
-				list_splice_init(&first->descs_list,
-						 &atchan->free_descs_list);
+				list_splice_tail_init(&first->descs_list,
+						      &atchan->free_descs_list);
 				return NULL;
 			}
 
@@ -1132,7 +1134,8 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 		if (!desc) {
 			dev_err(chan2dev(chan), "can't get descriptor\n");
 			if (first)
-				list_splice_init(&first->descs_list, &atchan->free_descs_list);
+				list_splice_tail_init(&first->descs_list,
+						      &atchan->free_descs_list);
 			return NULL;
 		}
 
@@ -1308,8 +1311,8 @@ at_xdmac_prep_dma_memset_sg(struct dma_chan *chan, struct scatterlist *sgl,
 						   sg_dma_len(sg),
 						   value);
 		if (!desc && first)
-			list_splice_init(&first->descs_list,
-					 &atchan->free_descs_list);
+			list_splice_tail_init(&first->descs_list,
+					      &atchan->free_descs_list);
 
 		if (!first)
 			first = desc;
@@ -1701,7 +1704,8 @@ static void at_xdmac_tasklet(struct tasklet_struct *t)
 
 		spin_lock_irq(&atchan->lock);
 		/* Move the xfer descriptors into the free descriptors list. */
-		list_splice_init(&desc->descs_list, &atchan->free_descs_list);
+		list_splice_tail_init(&desc->descs_list,
+				      &atchan->free_descs_list);
 		at_xdmac_advance_work(atchan);
 		spin_unlock_irq(&atchan->lock);
 	}
@@ -1850,7 +1854,8 @@ static int at_xdmac_device_terminate_all(struct dma_chan *chan)
 	/* Cancel all pending transfers. */
 	list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node) {
 		list_del(&desc->xfer_node);
-		list_splice_init(&desc->descs_list, &atchan->free_descs_list);
+		list_splice_tail_init(&desc->descs_list,
+				      &atchan->free_descs_list);
 	}
 
 	clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
-- 
2.25.1


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  parent reply	other threads:[~2021-12-15 11:10 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-15 11:01 [PATCH v3 00/12] dmaengine: at_xdmac: Various fixes Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 01/12] dmaengine: at_xdmac: Don't start transactions at tx_submit level Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 02/12] dmaengine: at_xdmac: Start transfer for cyclic channels in issue_pending Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 03/12] dmaengine: at_xdmac: Print debug message after realeasing the lock Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 04/12] dmaengine: at_xdmac: Fix concurrency over chan's completed_cookie Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 05/12] dmaengine: at_xdmac: Fix race for the tx desc callback Tudor Ambarus
2021-12-15 11:01 ` Tudor Ambarus [this message]
2021-12-15 11:01 ` [PATCH v3 07/12] dmaengine: at_xdmac: Fix concurrency over xfers_list Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 08/12] dmaengine: at_xdmac: Remove a level of indentation in at_xdmac_advance_work() Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 09/12] dmaengine: at_xdmac: Fix lld view setting Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 10/12] dmaengine: at_xdmac: Fix at_xdmac_lld struct definition Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 11/12] dmaengine: at_xdmac: Remove a level of indentation in at_xdmac_tasklet() Tudor Ambarus
2021-12-15 11:01 ` [PATCH v3 12/12] dmaengine: at_xdmac: Fix race over irq_status Tudor Ambarus
2022-01-05 10:20 ` [PATCH v3 00/12] dmaengine: at_xdmac: Various fixes Vinod Koul

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