[PATCH 16/21] dmaengine: tegra210-adma: Annotate struct tegra_adma 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_adma.

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

Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Cc: Laxman Dewangan <ldewangan@xxxxxxxxxx>
Cc: Jon Hunter <jonathanh@xxxxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
Cc: dmaengine@xxxxxxxxxxxxxxx
Cc: linux-tegra@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/dma/tegra210-adma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
index e557bada1510..cea33912a4c9 100644
--- a/drivers/dma/tegra210-adma.c
+++ b/drivers/dma/tegra210-adma.c
@@ -162,7 +162,7 @@ struct tegra_adma {
 	const struct tegra_adma_chip_data *cdata;
 
 	/* Last member of the structure */
-	struct tegra_adma_chan		channels[];
+	struct tegra_adma_chan		channels[] __counted_by(nr_channels);
 };
 
 static inline void tdma_write(struct tegra_adma *tdma, u32 reg, u32 val)
-- 
2.34.1