linux-kernel - [PATCH 1/2] dma-mapping: check dma_mask for streaming mapping allocs

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Date:   Tue, 22 Feb 2022 21:41:43 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Christoph Hellwig <hch@....de>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        akpm@...ux-foundation.org, cl@...ux.com, 42.hyeyoo@...il.com,
        penberg@...nel.org, rientjes@...gle.com, iamjoonsoo.kim@....com,
        vbabka@...e.cz, David.Laight@...lab.com, david@...hat.com,
        herbert@...dor.apana.org.au, davem@...emloft.net,
        linux-crypto@...r.kernel.org, steffen.klassert@...unet.com,
        netdev@...r.kernel.org, hca@...ux.ibm.com, gor@...ux.ibm.com,
        agordeev@...ux.ibm.com, borntraeger@...ux.ibm.com,
        svens@...ux.ibm.com, linux-s390@...r.kernel.org, michael@...le.cc,
        linux-i2c@...r.kernel.org, wsa@...nel.org
Subject: [PATCH 1/2] dma-mapping: check dma_mask for streaming mapping allocs

For newly added streaming mapping APIs, the internal core function
__dma_alloc_pages() should check dev->dma_mask, but not
ev->coherent_dma_mask which is for coherent mapping.

Meanwhile, just filter out gfp flags if they are any of
__GFP_DMA, __GFP_DMA32 and __GFP_HIGHMEM, but not fail it. This change
makes it  consistent with coherent mapping allocs.

Signed-off-by: Baoquan He <bhe@...hat.com>
---
 kernel/dma/mapping.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 9478eccd1c8e..e66847aeac67 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -543,10 +543,11 @@ static struct page *__dma_alloc_pages(struct device *dev, size_t size,
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
 
-	if (WARN_ON_ONCE(!dev->coherent_dma_mask))
-		return NULL;
-	if (WARN_ON_ONCE(gfp & (__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM)))
-		return NULL;
+	if (WARN_ON_ONCE(!dev->dma_mask))
+                return NULL;
+
+	/* let the implementation decide on the zone to allocate from: */
+        gfp &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM);
 
 	size = PAGE_ALIGN(size);
 	if (dma_alloc_direct(dev, ops))
-- 
2.31.1