[PATCH] dmaengine: fsl-edma: Annotate struct struct fsl_edma_engine 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 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 struct fsl_edma_engine.

Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Cc: dmaengine@xxxxxxxxxxxxxxx
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/dma/fsl-edma-common.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/fsl-edma-common.h b/drivers/dma/fsl-edma-common.h
index 40d50cc3d75a..bb5221158a77 100644
--- a/drivers/dma/fsl-edma-common.h
+++ b/drivers/dma/fsl-edma-common.h
@@ -225,7 +225,7 @@ struct fsl_edma_engine {
 	bool			big_endian;
 	struct edma_regs	regs;
 	u64			chan_masked;
-	struct fsl_edma_chan	chans[];
+	struct fsl_edma_chan	chans[] __counted_by(n_chans);
 };
 
 #define edma_read_tcdreg(chan, __name)				\
-- 
2.34.1