linux-kernel - [PATCH v2] dma-mapping: Use dma_get_mask in dma_addressing

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Message-Id: <20190722165149.3763-1-eric.auger@redhat.com>
Date:   Mon, 22 Jul 2019 18:51:49 +0200
From:   Eric Auger <eric.auger@...hat.com>
To:     eric.auger.pro@...il.com, eric.auger@...hat.com, hch@....de,
        m.szyprowski@...sung.com, robin.murphy@....com, mst@...hat.com,
        jasowang@...hat.com, virtualization@...ts.linux-foundation.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] dma-mapping: Use dma_get_mask in dma_addressing_limited

We currently have cases where the dma_addressing_limited() gets
called with dma_mask unset. This causes a NULL pointer dereference.

Use dma_get_mask() accessor to prevent the crash.

Fixes: b866455423e0 ("dma-mapping: add a dma_addressing_limited helper")
Signed-off-by: Eric Auger <eric.auger@...hat.com>

---

v1 -> v2:
- was [PATCH 1/2] dma-mapping: Protect dma_addressing_limited
  against NULL dma_mask
- Use dma_get_mask
---
 include/linux/dma-mapping.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index e11b115dd0e4..f7d1eea32c78 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -689,8 +689,8 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
  */
 static inline bool dma_addressing_limited(struct device *dev)
 {
-	return min_not_zero(*dev->dma_mask, dev->bus_dma_mask) <
-		dma_get_required_mask(dev);
+	return min_not_zero(dma_get_mask(dev), dev->bus_dma_mask) <
+			    dma_get_required_mask(dev);
 }
 
 #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS
-- 
2.20.1