[PATCH 01/21] dmaengine: apple-admac: Annotate struct admac_data 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 admac_data.

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

Cc: Vinod Koul <vkoul at kernel.org>
Cc: Hector Martin <marcan at marcan.st>
Cc: Sven Peter <sven at svenpeter.dev>
Cc: Alyssa Rosenzweig <alyssa at rosenzweig.io>
Cc: asahi at lists.linux.dev
Cc: linux-arm-kernel at lists.infradead.org
Cc: dmaengine at vger.kernel.org
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/dma/apple-admac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/apple-admac.c b/drivers/dma/apple-admac.c
index 3af795635c5c..ff46260b6ebc 100644
--- a/drivers/dma/apple-admac.c
+++ b/drivers/dma/apple-admac.c
@@ -128,7 +128,7 @@ struct admac_data {
 	int irq;
 	int irq_index;
 	int nchannels;
-	struct admac_chan channels[];
+	struct admac_chan channels[] __counted_by(nchannels);
 };
 
 struct admac_tx {
-- 
2.34.1