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dmaengine: zynqmp_dma: Reject zero-length memcpy transfers

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Zero-length prep_memcpy() needlessly consumed a descriptor slot. Reject
zero-length memcpy at prep time and document the behaviour.

Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260814045616.1661199-8-nagendra.golla@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Golla Nagendra 2026-08-14 10:26:15 +05:30 committed by Vinod Koul
parent bff5f96e79
commit cc38c812cb
1 changed files with 5 additions and 1 deletions
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6
drivers/dma/xilinx/zynqmp_dma.c
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@ -837,7 +837,8 @@ static void zynqmp_dma_synchronize(struct dma_chan *dchan)
* @len: Transfer length
* @flags: transfer ack flags
*
* Return: Async transaction descriptor on success and NULL on failure
* Return: Async transaction descriptor on success and NULL on failure or
* zero length transfer
*/
static struct dma_async_tx_descriptor *zynqmp_dma_prep_memcpy(
struct dma_chan *dchan, dma_addr_t dma_dst,
@ -852,6 +853,9 @@ static struct dma_async_tx_descriptor *zynqmp_dma_prep_memcpy(
chan = to_chan(dchan);
if (!len)
return NULL;
desc_cnt = DIV_ROUND_UP(len, ZYNQMP_DMA_MAX_TRANS_LEN);
spin_lock_irqsave(&chan->lock, irqflags);