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authorJohannes Thumshirn <jthumshirn@suse.de>2019-04-03 11:15:19 +0200
committerJens Axboe <axboe@kernel.dk>2019-04-04 09:30:37 -0600
commit2b24e6f63ac9e817630424c6d8f008256348dfc4 (patch)
tree04e523e6f47a8d5b251f86ad827e2ab3ee8c7640
parent2bc13b83e6298486371761de503faeffd15b7534 (diff)
block: bio: ensure newly added bio flags don't override BVEC_POOL_IDX
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>
-rw-r--r--block/bio.c3
-rw-r--r--include/linux/blk_types.h29
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 */