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From:   Christoph Hellwig <hch@lst.de>
To:     Pawel Osciak <pawel@osciak.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        =?UTF-8?q?Niklas=20S=C3=B6derlund?= 
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Cc:     Russell King <linux@armlinux.org.uk>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        iommu@lists.linux-foundation.org,
        linux-arm-kernel@lists.infradead.org,
        linuxppc-dev@lists.ozlabs.org, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org, Robin Murphy <robin.murphy@arm.com>
Subject: [PATCH 2/3] dma-mapping: don't BUG when calling dma_map_resource on RAM
Date:   Fri, 18 Jan 2019 12:37:26 +0100
Message-Id: <20190118113727.3270-3-hch@lst.de>
In-Reply-To: <20190118113727.3270-1-hch@lst.de>
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Use WARN_ON_ONCE to print a stack trace and return a proper error
code instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
---
 include/linux/dma-mapping.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 9842085e6774..b904d55247ab 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -353,7 +353,8 @@ static inline dma_addr_t dma_map_resource(struct device *dev,
 	BUG_ON(!valid_dma_direction(dir));
 
 	/* Don't allow RAM to be mapped */
-	BUG_ON(pfn_valid(PHYS_PFN(phys_addr)));
+	if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr))))
+		return DMA_MAPPING_ERROR;
 
 	if (dma_is_direct(ops))
 		addr = dma_direct_map_resource(dev, phys_addr, size, dir, attrs);
-- 
2.20.1