diff options
Diffstat (limited to 'drivers/md/bcache/util.c')
| -rw-r--r-- | drivers/md/bcache/util.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c index e548b8b51322..a23cd6a14b74 100644 --- a/drivers/md/bcache/util.c +++ b/drivers/md/bcache/util.c @@ -249,6 +249,13 @@ uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done) : 0; } +/* + * Generally it isn't good to access .bi_io_vec and .bi_vcnt directly, + * the preferred way is bio_add_page, but in this case, bch_bio_map() + * supposes that the bvec table is empty, so it is safe to access + * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is + * supported. + */ void bch_bio_map(struct bio *bio, void *base) { size_t size = bio->bi_iter.bi_size; @@ -276,6 +283,33 @@ start: bv->bv_len = min_t(size_t, PAGE_SIZE - bv->bv_offset, } } +/** + * bch_bio_alloc_pages - allocates a single page for each bvec in a bio + * @bio: bio to allocate pages for + * @gfp_mask: flags for allocation + * + * Allocates pages up to @bio->bi_vcnt. + * + * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are + * freed. + */ +int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask) +{ + int i; + struct bio_vec *bv; + + bio_for_each_segment_all(bv, bio, i) { + bv->bv_page = alloc_page(gfp_mask); + if (!bv->bv_page) { + while (--bv >= bio->bi_io_vec) + __free_page(bv->bv_page); + return -ENOMEM; + } + } + + return 0; +} + /* * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group (Any * use permitted, subject to terms of PostgreSQL license; see.) |