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. Signed-off-by: Johannes Thumshirn <[email protected]> --- This used to be part of my bio patchset but as it's a) not clear why we end up calling bio_put() on the on-stack bio and b) the needed prep patch for the fix introduces a regression, I've decided to sent this patch out as it's valid on it's own. I dropped Hannes' and Christoph's R-b though, as the context changed. --- block/bio.c | 3 +++ include/linux/blk_types.h | 29 ++++++++++++++++------------- 2 files changed, 19 insertions(+), 13 deletions(-) diff --git a/block/bio.c b/block/bio.c index 8d516d508ae3..c2592c5d70b9 100644 --- a/block/bio.c +++ b/block/bio.c @@ -2218,6 +2218,9 @@ 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 791fee35df88..be418275763c 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -215,21 +215,24 @@ struct bio { /* * bio flags */ -#define BIO_NO_PAGE_REF 0 /* don't put release vec pages */ -#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 +enum { + BIO_NO_PAGE_REF, /* don't put release vec pages */ + BIO_SEG_VALID, /* bi_phys_segments valid */ + 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
