Since REQ_OP_BITS == 3 and __REQ_NR_BITS == 30 it is not that hard to pass an op_flags argument to bio_set_op_attrs() that is larger than the number of bits reserved for the op_flags argument. Complain if this happens. Additionally, ensure that negative arguments trigger a complaint (1 << ... is signed while 1U << ... is unsigned; adding 0U to an integer expression causes it to be promoted to an unsigned type).
Signed-off-by: Bart Van Assche <[email protected]> Cc: Mike Christie <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: Damien Le Moal <[email protected]> --- include/linux/blk_types.h | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 311fa2f..53ee1a2 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -93,11 +93,18 @@ struct bio { #define bio_flags(bio) ((bio)->bi_opf & ((1 << BIO_OP_SHIFT) - 1)) #define bio_op(bio) ((bio)->bi_opf >> BIO_OP_SHIFT) -#define bio_set_op_attrs(bio, op, op_flags) do { \ - WARN_ON(op >= (1 << REQ_OP_BITS)); \ - (bio)->bi_opf = bio_flags(bio); \ - (bio)->bi_opf |= ((unsigned int) (op) << BIO_OP_SHIFT); \ - (bio)->bi_opf |= op_flags; \ +#define bio_set_op_attrs(bio, op, op_flags) do { \ + if (__builtin_constant_p(op)) \ + BUILD_BUG_ON((op) + 0U >= (1U << REQ_OP_BITS)); \ + else \ + WARN_ON_ONCE((op) + 0U >= (1U << REQ_OP_BITS)); \ + if (__builtin_constant_p(op_flags)) \ + BUILD_BUG_ON((op_flags) + 0U >= (1U << BIO_OP_SHIFT)); \ + else \ + WARN_ON_ONCE((op_flags) + 0U >= (1U << BIO_OP_SHIFT)); \ + (bio)->bi_opf = bio_flags(bio); \ + (bio)->bi_opf |= (((op) + 0U) << BIO_OP_SHIFT); \ + (bio)->bi_opf |= (op_flags); \ } while (0) #define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs) -- 2.10.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
