[PATCH 1/2] block: bio: ensure newly added bio flags don't override BVEC_POOL_IDX
From: Johannes Thumshirn <hidden>
Date: 2019-03-21 12:30:53
Also in:
linux-fsdevel
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
With the introduction of BIO_ALLOCED we've used up all available bits in bio::bi_flags. Make sure no-one adds a new one and thus overrides the BVEC_POOL_IDX Signed-off-by: Johannes Thumshirn <redacted> --- block/bio.c | 8 ++++++++ include/linux/blk_types.h | 31 +++++++++++++++++-------------- 2 files changed, 25 insertions(+), 14 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 4db1008309ed..8c689aed46a0 100644
--- a/block/bio.c
+++ b/block/bio.c@@ -2126,12 +2126,20 @@ static void __init biovec_init_slabs(void) } } +static inline void bio_flag_buildtime_check(void) +{ + BUILD_BUG_ON(BIO_FLAG_LAST > BVEC_POOL_OFFSET); +} + static int __init init_bio(void) { bio_slab_max = 2; bio_slab_nr = 0; bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab), GFP_KERNEL); + + bio_flag_buildtime_check(); + if (!bio_slabs) panic("bio: can't allocate bios\n");
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d66bf5f32610..0273bad71a96 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h@@ -215,20 +215,23 @@ struct bio { /* * bio flags */ -#define BIO_SEG_VALID 1 /* bi_phys_segments valid */ -#define BIO_CLONED 2 /* doesn't own data */ -#define BIO_BOUNCED 3 /* bio is a bounce bio */ -#define BIO_USER_MAPPED 4 /* contains user pages */ -#define BIO_NULL_MAPPED 5 /* contains invalid user pages */ -#define BIO_QUIET 6 /* Make BIO Quiet */ -#define BIO_CHAIN 7 /* chained bio, ->bi_remaining in effect */ -#define BIO_REFFED 8 /* bio has elevated ->bi_cnt */ -#define BIO_THROTTLED 9 /* This bio has already been subjected to - * throttling rules. Don't do it again. */ -#define BIO_TRACE_COMPLETION 10 /* bio_endio() should trace the final completion - * of this bio. */ -#define BIO_QUEUE_ENTERED 11 /* can use blk_queue_enter_live() */ -#define BIO_TRACKED 12 /* set if bio goes through the rq_qos path */ +enum { + BIO_SEG_VALID = 1, /* bi_phys_segments valid */ + BIO_CLONED = 2, /* doesn't own data */ + BIO_BOUNCED = 3, /* bio is a bounce bio */ + BIO_USER_MAPPED = 4, /* contains user pages */ + BIO_NULL_MAPPED = 5, /* contains invalid user pages */ + BIO_QUIET = 6, /* Make BIO Quiet */ + BIO_CHAIN = 7, /* chained bio, ->bi_remaining in effect */ + BIO_REFFED = 8, /* bio has elevated ->bi_cnt */ + BIO_THROTTLED = 9, /* This bio has already been subjected to + * throttling rules. Don't do it again. */ + BIO_TRACE_COMPLETION = 10, /* bio_endio() should trace the final completion + * of this bio. */ + BIO_QUEUE_ENTERED = 11, /* can use blk_queue_enter_live() */ + BIO_TRACKED = 12, /* set if bio goes through the rq_qos path */ + BIO_FLAG_LAST +}; /* See BVEC_POOL_OFFSET below before adding new flags */
--
2.16.4