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block: Kill bio_segments()/bi_vcnt usage

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When we start sharing biovecs, keeping bi_vcnt accurate for splits is
going to be error prone - and unnecessary, if we refactor some code.

So bio_segments() has to go - but most of the existing users just needed
to know if the bio had multiple segments, which is easier - add a
bio_multiple_segments() for them.

(Two of the current uses of bio_segments() are going to go away in a
couple patches, but the current implementation of bio_segments() is
unsafe as soon as we start doing driver conversions for immutable
biovecs - so implement a dumb version for bisectability, it'll go away
in a couple patches)

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Neil Brown <neilb@suse.de>
Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com>
Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
This commit is contained in:
Kent Overstreet 2013-09-24 16:26:05 -07:00
parent d57a5f7c66
commit 458b76ed2f
10 changed files with 93 additions and 86 deletions
Download patch file Download diff file Expand all files Collapse all files

81
include/linux/bio.h
View file

@ -97,13 +97,46 @@
#define bio_offset(bio) bio_iter_offset((bio), (bio)->bi_iter)
#define bio_iovec(bio) bio_iter_iovec((bio), (bio)->bi_iter)
#define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_iter.bi_idx)
#define bio_multiple_segments(bio) \
((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
#define bio_sectors(bio) ((bio)->bi_iter.bi_size >> 9)
#define bio_end_sector(bio) ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
/*
* Check whether this bio carries any data or not. A NULL bio is allowed.
*/
static inline bool bio_has_data(struct bio *bio)
{
if (bio &&
bio->bi_iter.bi_size &&
!(bio->bi_rw & REQ_DISCARD))
return true;
return false;
}
static inline bool bio_is_rw(struct bio *bio)
{
if (!bio_has_data(bio))
return false;
if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
return false;
return true;
}
static inline bool bio_mergeable(struct bio *bio)
{
if (bio->bi_rw & REQ_NOMERGE_FLAGS)
return false;
return true;
}
static inline unsigned int bio_cur_bytes(struct bio *bio)
{
if (bio->bi_vcnt)
if (bio_has_data(bio))
return bio_iovec(bio).bv_len;
else /* dataless requests such as discard */
return bio->bi_iter.bi_size;
@ -111,7 +144,7 @@ static inline unsigned int bio_cur_bytes(struct bio *bio)
static inline void *bio_data(struct bio *bio)
{
if (bio->bi_vcnt)
if (bio_has_data(bio))
return page_address(bio_page(bio)) + bio_offset(bio);
return NULL;
@ -221,6 +254,18 @@ static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
static inline unsigned bio_segments(struct bio *bio)
{
unsigned segs = 0;
struct bio_vec bv;
struct bvec_iter iter;
bio_for_each_segment(bv, bio, iter)
segs++;
return segs;
}
/*
* get a reference to a bio, so it won't disappear. the intended use is
* something like:
@ -434,36 +479,6 @@ static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
__bio_kmap_irq((bio), (bio)->bi_iter.bi_idx, (flags))
#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
/*
* Check whether this bio carries any data or not. A NULL bio is allowed.
*/
static inline bool bio_has_data(struct bio *bio)
{
if (bio && bio->bi_vcnt)
return true;
return false;
}
static inline bool bio_is_rw(struct bio *bio)
{
if (!bio_has_data(bio))
return false;
if (bio->bi_rw & REQ_WRITE_SAME)
return false;
return true;
}
static inline bool bio_mergeable(struct bio *bio)
{
if (bio->bi_rw & REQ_NOMERGE_FLAGS)
return false;
return true;
}
/*
* BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
*