dmaengine: fsl-edma: Annotate struct struct fsl_edma_engine with __counted_by

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 <[email protected]>

Cc [email protected]

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

Signed-off-by Kees Cook <[email protected]>

---
  drivers/dma/fsl-edma-common.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

drivers/dma/fsl-edma-common.h +1 -1

index 40d50cc3d75a..bb5221158a77 100644
@@ -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)				\

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.

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