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 <bart.vanassche@xxxxxxxxxxx>
Cc: Mike Christie <mchristi@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Damien Le Moal <damien.lemoal@xxxxxxxx>
---
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
--
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