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block: bio: ensure newly added bio flags don't override BVEC_POOL_IDX

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With the introduction of BIO_NO_PAGE_REF we've used up all available bits
in bio::bi_flags.

Convert the defines of the flags to an enum and add a BUILD_BUG_ON() call
to make sure no-one adds a new one and thus overrides the BVEC_POOL_IDX
causing crashes.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Johannes Thumshirn 2019-04-03 11:15:19 +02:00 committed by Jens Axboe
parent 2bc13b83e6
commit 2b24e6f63a
2 changed files with 19 additions and 13 deletions
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3
block/bio.c
View File

@ -2218,6 +2218,9 @@ static int __init init_bio(void)
bio_slab_nr = 0; bio_slab_nr = 0;
bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab), bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab),
GFP_KERNEL); GFP_KERNEL);
BUILD_BUG_ON(BIO_FLAG_LAST > BVEC_POOL_OFFSET);
if (!bio_slabs) if (!bio_slabs)
panic("bio: can't allocate bios\n"); panic("bio: can't allocate bios\n");

29
include/linux/blk_types.h
View File

@ -215,21 +215,24 @@ struct bio {
/* /*
* bio flags * bio flags
*/ */
#define BIO_NO_PAGE_REF 0 /* don't put release vec pages */ enum {
#define BIO_SEG_VALID 1 /* bi_phys_segments valid */ BIO_NO_PAGE_REF, /* don't put release vec pages */
#define BIO_CLONED 2 /* doesn't own data */ BIO_SEG_VALID, /* bi_phys_segments valid */
#define BIO_BOUNCED 3 /* bio is a bounce bio */ BIO_CLONED, /* doesn't own data */
#define BIO_USER_MAPPED 4 /* contains user pages */ BIO_BOUNCED, /* bio is a bounce bio */
#define BIO_NULL_MAPPED 5 /* contains invalid user pages */ BIO_USER_MAPPED, /* contains user pages */
#define BIO_QUIET 6 /* Make BIO Quiet */ BIO_NULL_MAPPED, /* contains invalid user pages */
#define BIO_CHAIN 7 /* chained bio, ->bi_remaining in effect */ BIO_QUIET, /* Make BIO Quiet */
#define BIO_REFFED 8 /* bio has elevated ->bi_cnt */ BIO_CHAIN, /* chained bio, ->bi_remaining in effect */
#define BIO_THROTTLED 9 /* This bio has already been subjected to BIO_REFFED, /* bio has elevated ->bi_cnt */
BIO_THROTTLED, /* This bio has already been subjected to
* throttling rules. Don't do it again. */ * 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. */ * of this bio. */
#define BIO_QUEUE_ENTERED 11 /* can use blk_queue_enter_live() */ BIO_QUEUE_ENTERED, /* can use blk_queue_enter_live() */
#define BIO_TRACKED 12 /* set if bio goes through the rq_qos path */ BIO_TRACKED, /* set if bio goes through the rq_qos path */
BIO_FLAG_LAST
};
/* See BVEC_POOL_OFFSET below before adding new flags */ /* See BVEC_POOL_OFFSET below before adding new flags */