linux-kernel - [PATCH 05/10] dmaengine: at_hdmac: Switch atomic allocations to GFP

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Date:   Thu, 23 Jan 2020 14:03:09 +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 05/10] dmaengine: at_hdmac: Switch atomic allocations to
 GFP_NOWAIT

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

Avoids sleeping without depleting the emergency pool.
The rationale being that in most cases a dma device is either
offloading an operation that will automatically fallback to
software when the descriptor allocation fails, or we can simply poll
and wait for the dma device to release some in use descriptors.

Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
---
 drivers/dma/at_hdmac.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 44d998bc894b..8e8e04bd1b28 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -147,7 +147,7 @@ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
 
 	/* no more descriptor available in initial pool: create one more */
 	if (!ret)
-		ret = atc_alloc_descriptor(&atchan->chan_common, GFP_ATOMIC);
+		ret = atc_alloc_descriptor(&atchan->chan_common, GFP_NOWAIT);
 
 	return ret;
 }
@@ -931,7 +931,7 @@ atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
 		return NULL;
 	}
 
-	vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC, &paddr);
+	vaddr = dma_pool_alloc(atdma->memset_pool, GFP_NOWAIT, &paddr);
 	if (!vaddr) {
 		dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
 			__func__);
@@ -989,7 +989,7 @@ atc_prep_dma_memset_sg(struct dma_chan *chan,
 		return NULL;
 	}
 
-	vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC, &paddr);
+	vaddr = dma_pool_alloc(atdma->memset_pool, GFP_NOWAIT, &paddr);
 	if (!vaddr) {
 		dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
 			__func__);
-- 
2.23.0