[PATCH v2 2/3] block: bio: ensure newly added bio flags don't override BVEC_POOL_IDX
From: Johannes Thumshirn <hidden>
Date: 2019-03-22 13:14:03
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 | 3 +++ include/linux/blk_types.h | 25 ++++++++++++++----------- 2 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index a79b2bbcffd0..87a515e93bee 100644
--- a/block/bio.c
+++ b/block/bio.c@@ -2198,6 +2198,9 @@ static int __init init_bio(void) bio_slab_nr = 0; bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab), GFP_KERNEL); + + BUILD_BUG_ON(BIO_FLAG_LAST > BVEC_POOL_OFFSET); + 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 472059e92071..1d28992a20f0 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h@@ -215,19 +215,22 @@ struct bio { /* * bio flags */ -#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 +enum { + BIO_CLONED, /* doesn't own data */ + BIO_BOUNCED, /* bio is a bounce bio */ + BIO_USER_MAPPED, /* contains user pages */ + BIO_NULL_MAPPED, /* contains invalid user pages */ + BIO_QUIET, /* Make BIO Quiet */ + BIO_CHAIN, /* chained bio, ->bi_remaining in effect */ + BIO_REFFED, /* bio has elevated ->bi_cnt */ + BIO_THROTTLED, /* 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 + BIO_TRACE_COMPLETION, /* 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 */ + BIO_QUEUE_ENTERED, /* can use blk_queue_enter_live() */ + BIO_TRACKED, /* set if bio goes through the rq_qos path */ + BIO_FLAG_LAST +}; /* See BVEC_POOL_OFFSET below before adding new flags */
--
2.16.4