mtd: rawnand: Annotate struct mtk_nfc_nand_chip 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
mtk_nfc_nand_chip.

Cc: Miquel Raynal <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Vignesh Raghavendra <[email protected]>
Cc: Matthias Brugger <[email protected]>
Cc: AngeloGioacchino Del Regno <[email protected]>
Cc: "Gustavo A. R. Silva" <[email protected]>
Cc: Heiko Stuebner <[email protected]>
Cc: Martin Blumenstingl <[email protected]>
Cc: Thierry Reding <[email protected]>
Cc: Roger Quadros <[email protected]>
Cc: "Uwe Kleine-König" <[email protected]>
Cc: Cai Huoqing <[email protected]>
Cc: Chuanhong Guo <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Li Zetao <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [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]>
Reviewed-by: Gustavo A. R. Silva <[email protected]>
Signed-off-by: Miquel Raynal <[email protected]>
Link: https://lore.kernel.org/linux-mtd/[email protected]

Author: kees

drivers/mtd/nand/raw/mtk_nand.c

@@ -130,7 +130,7 @@ struct mtk_nfc_nand_chip {
 	u32 spare_per_sector;
 
 	int nsels;
-	u8 sels[];
+	u8 sels[] __counted_by(nsels);
 	/* nothing after this field */
 };