[PATCH v4 24/24] block: Add BIO_SUBMITTED flag, kill BIO_CLONED

From: Kent Overstreet
Date: Mon Oct 15 2012 - 16:19:18 EST


BIO_CLONED wasn't very useful, and didn't have very clear semantics, so
kill it.

Replace it with a more useful flag - BIO_SUBMITTED means the bio has
been passed to generic_make_request() and the bvec can no longer be
modified.

Roll both changes into the same patch so we can steal the old bit for
the new flag.

Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
CC: Jens Axboe <axboe@xxxxxxxxx>
CC: Alasdair Kergon <agk@xxxxxxxxxx>
CC: dm-devel@xxxxxxxxxx
CC: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
block/blk-core.c | 2 ++
drivers/md/dm.c | 1 -
fs/bio-integrity.c | 1 -
fs/bio.c | 8 +++++---
include/linux/blk_types.h | 2 +-
5 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index df9bb5f..fcf4335 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1631,6 +1631,8 @@ generic_make_request_checks(struct bio *bio)

might_sleep();

+ bio->bi_flags |= 1 << BIO_SUBMITTED;
+
if (bio_check_eod(bio, nr_sectors))
goto end_io;

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8378797..777e70d 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1065,7 +1065,6 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
clone->bi_size = to_bytes(len);
clone->bi_io_vec->bv_offset = offset;
clone->bi_io_vec->bv_len = clone->bi_size;
- clone->bi_flags |= 1 << BIO_CLONED;

if (bio_integrity(bio)) {
bio_integrity_clone(clone, bio, GFP_NOIO);
diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index 8fb4291..352eb0b 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -625,7 +625,6 @@ void bio_integrity_trim(struct bio *bio, unsigned int offset,

BUG_ON(bip == NULL);
BUG_ON(bi == NULL);
- BUG_ON(!bio_flagged(bio, BIO_CLONED));

nr_sectors = bio_integrity_hw_sectors(bi, sectors);
bip->bip_sector = bip->bip_sector + offset;
diff --git a/fs/bio.c b/fs/bio.c
index 5dc8441..e8625dc 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -531,7 +531,7 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
*/
bio->bi_sector = bio_src->bi_sector;
bio->bi_bdev = bio_src->bi_bdev;
- bio->bi_flags |= 1 << BIO_CLONED;
+ bio->bi_flags |= (bio_src->bi_flags & (1 << BIO_SUBMITTED));
bio->bi_rw = bio_src->bi_rw;
bio->bi_vcnt = bio_src->bi_vcnt;
bio->bi_size = bio_src->bi_size;
@@ -604,9 +604,9 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
struct bio_vec *bvec;

/*
- * cloned bio must not modify vec list
+ * submitted bio must not modify vec list
*/
- if (unlikely(bio_flagged(bio, BIO_CLONED)))
+ if (unlikely(bio_flagged(bio, BIO_SUBMITTED)))
return 0;

if (((bio->bi_size + len) >> 9) > max_sectors)
@@ -844,6 +844,8 @@ int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
int i;
struct bio_vec *bv;

+ BUG_ON(bio_flagged(bio, BIO_SUBMITTED));
+
bio_for_each_segment_all(bv, bio, i) {
bv->bv_page = alloc_page(gfp_mask);
if (!bv->bv_page) {
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 538289f..edc5cb9 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -103,7 +103,7 @@ struct bio {
#define BIO_RW_BLOCK 1 /* RW_AHEAD set, and read/write would block */
#define BIO_EOF 2 /* out-out-bounds error */
#define BIO_SEG_VALID 3 /* bi_phys_segments valid */
-#define BIO_CLONED 4 /* doesn't own data */
+#define BIO_SUBMITTED 4 /* bio has been submitted */
#define BIO_BOUNCED 5 /* bio is a bounce bio */
#define BIO_USER_MAPPED 6 /* contains user pages */
#define BIO_EOPNOTSUPP 7 /* not supported */
--
1.7.12

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