[PATCH 15/21] dmaengine: tegra: Annotate struct tegra_dma_desc with __counted_by

[Kees Cook]

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct tegra_dma_desc.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Vinod Koul <vkoul at kernel.org>
Cc: Laxman Dewangan <ldewangan at nvidia.com>
Cc: Jon Hunter <jonathanh at nvidia.com>
Cc: Thierry Reding <thierry.reding at gmail.com>
Cc: dmaengine at vger.kernel.org
Cc: linux-tegra at vger.kernel.org
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/dma/tegra186-gpc-dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
index 33b101001100..5e3d5f5d1e20 100644
--- a/drivers/dma/tegra186-gpc-dma.c
+++ b/drivers/dma/tegra186-gpc-dma.c
@@ -221,7 +221,7 @@ struct tegra_dma_desc {
 	unsigned int sg_count;
 	struct virt_dma_desc vd;
 	struct tegra_dma_channel *tdc;
-	struct tegra_dma_sg_req sg_req[];
+	struct tegra_dma_sg_req sg_req[] __counted_by(sg_count);
 };
 
 /*
-- 
2.34.1