[PATCH 04/21] dmaengine: fsl-edma: Annotate struct fsl_edma_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 fsl_edma_desc.

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

Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Cc: dmaengine@xxxxxxxxxxxxxxx
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 004ec4a6bc86..fdbc79787643 100644
--- a/drivers/dma/fsl-edma-common.h
+++ b/drivers/dma/fsl-edma-common.h
@@ -135,7 +135,7 @@ struct fsl_edma_desc {
 	bool				iscyclic;
 	enum dma_transfer_direction	dirn;
 	unsigned int			n_tcds;
-	struct fsl_edma_sw_tcd		tcd[];
+	struct fsl_edma_sw_tcd		tcd[] __counted_by(n_tcds);
 };
 
 enum edma_version {
-- 
2.34.1