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From: Christoph Hellwig <hch@lst.de>
To: iommu@lists.linux-foundation.org
Cc: Robin Murphy <robin.murphy@arm.com>,
	David Rientjes <rientjes@google.com>
Subject: [PATCH 07/11] dma-direct: fail allocations that can't be made coherent
Date: Thu, 11 Nov 2021 07:50:23 +0100	[thread overview]
Message-ID: <20211111065028.32761-8-hch@lst.de> (raw)
In-Reply-To: <20211111065028.32761-1-hch@lst.de>

If the architecture can't remap or set an address uncached there is no way
to fullfill a request for a coherent allocation.  Return NULL in that case.
Note that this case currently does not happen, so this is a theoretical
fixup and/or a preparation for eventually supporting platforms that
can't support coherent allocations with the generic code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/dma/direct.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index f9658fe18498c..a13017656ecae 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -233,8 +233,9 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 				return dma_direct_alloc_from_pool(dev, size,
 						dma_handle, gfp);
 		} else {
-			if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED))
-				set_uncached = true;
+			if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED))
+				return NULL;
+			set_uncached = true;
 		}
 	}
 
-- 
2.30.2

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  parent reply	other threads:[~2021-11-11  6:50 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-11  6:50 dma-direct fixes and cleanups v3 Christoph Hellwig
2021-11-11  6:50 ` [PATCH 01/11] dma-direct: factor out dma_set_{de,en}crypted helpers Christoph Hellwig
2021-11-11  6:50 ` [PATCH 02/11] dma-direct: don't call dma_set_decrypted for remapped allocations Christoph Hellwig
2021-11-11  6:50 ` [PATCH 03/11] dma-direct: always leak memory that can't be re-encrypted Christoph Hellwig
2021-12-06 16:32   ` Robin Murphy
2021-12-07 11:48     ` Christoph Hellwig
2021-11-11  6:50 ` [PATCH 04/11] dma-direct: clean up the remapping checks in dma_direct_alloc Christoph Hellwig
2021-12-06 16:33   ` Robin Murphy
2021-12-07 11:49     ` Christoph Hellwig
2021-12-07 12:43       ` Robin Murphy
2021-11-11  6:50 ` [PATCH 05/11] dma-direct: factor out a helper for DMA_ATTR_NO_KERNEL_MAPPING allocations Christoph Hellwig
2021-11-11  6:50 ` [PATCH 06/11] dma-direct: refactor the !coherent checks in dma_direct_alloc Christoph Hellwig
2021-12-06 16:33   ` Robin Murphy
2021-11-11  6:50 ` Christoph Hellwig [this message]
2021-12-06 16:33   ` [PATCH 07/11] dma-direct: fail allocations that can't be made coherent Robin Murphy
2021-11-11  6:50 ` [PATCH 08/11] dma-direct: warn if there is no pool for force unencrypted allocations Christoph Hellwig
2021-11-11  6:50 ` [PATCH 09/11] dma-direct: drop two CONFIG_DMA_RESTRICTED_POOL conditionals Christoph Hellwig
2021-11-11  6:50 ` [PATCH 10/11] dma-direct: factor the swiotlb code out of __dma_direct_alloc_pages Christoph Hellwig
2021-11-11  6:50 ` [PATCH 11/11] dma-direct: add a dma_direct_use_pool helper Christoph Hellwig
2021-12-08 15:44   ` Marek Szyprowski
2021-12-08 15:48     ` Christoph Hellwig
2021-11-16 11:31 ` dma-direct fixes and cleanups v3 Robin Murphy
2021-11-17  5:51   ` Christoph Hellwig

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