xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

block: Kill bio_segments()/bi_vcnt usage

Browse Source 
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

51
drivers/md/bcache/io.c
View File

@@ -24,7 +24,8 @@ static void bch_generic_make_request_hack(struct bio *bio)
if (bio->bi_iter.bi_idx) {
struct bio_vec bv;
struct bvec_iter iter;
struct bio *clone = bio_alloc(GFP_NOIO, bio_segments(bio));
unsigned segs = bio_segments(bio);
struct bio *clone = bio_alloc(GFP_NOIO, segs);
bio_for_each_segment(bv, bio, iter)
clone->bi_io_vec[clone->bi_vcnt++] = bv;
@@ -32,7 +33,7 @@ static void bch_generic_make_request_hack(struct bio *bio)
clone->bi_iter.bi_sector = bio->bi_iter.bi_sector;
clone->bi_bdev = bio->bi_bdev;
clone->bi_rw = bio->bi_rw;
clone->bi_vcnt = bio_segments(bio);
clone->bi_vcnt = segs;
clone->bi_iter.bi_size = bio->bi_iter.bi_size;
clone->bi_private = bio;
@@ -133,40 +134,32 @@ out:
static unsigned bch_bio_max_sectors(struct bio *bio)
{
unsigned ret = bio_sectors(bio);
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
unsigned max_segments = min_t(unsigned, BIO_MAX_PAGES,
queue_max_segments(q));
struct bio_vec bv;
struct bvec_iter iter;
unsigned ret = 0, seg = 0;
if (bio->bi_rw & REQ_DISCARD)
return min(ret, q->limits.max_discard_sectors);
return min(bio_sectors(bio), q->limits.max_discard_sectors);
if (bio_segments(bio) > max_segments ||
q->merge_bvec_fn) {
struct bio_vec bv;
struct bvec_iter iter;
unsigned seg = 0;
bio_for_each_segment(bv, bio, iter) {
struct bvec_merge_data bvm = {
.bi_bdev = bio->bi_bdev,
.bi_sector = bio->bi_iter.bi_sector,
.bi_size = ret << 9,
.bi_rw = bio->bi_rw,
};
ret = 0;
if (seg == min_t(unsigned, BIO_MAX_PAGES,
queue_max_segments(q)))
break;
bio_for_each_segment(bv, bio, iter) {
struct bvec_merge_data bvm = {
.bi_bdev = bio->bi_bdev,
.bi_sector = bio->bi_iter.bi_sector,
.bi_size = ret << 9,
.bi_rw = bio->bi_rw,
};
if (q->merge_bvec_fn &&
q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
break;
if (seg == max_segments)
break;
if (q->merge_bvec_fn &&
q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
break;
seg++;
ret += bv.bv_len >> 9;
}
seg++;
ret += bv.bv_len >> 9;
}
ret = min(ret, queue_max_sectors(q));