diff options
| author | Ming Lei <ming.lei@redhat.com> | 2019-03-17 18:01:08 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-04-01 12:11:34 -0600 |
| commit | 190470871ae28da7bdb3909f6124385c8472fc97 (patch) | |
| tree | 6af7ea3cda825066245aedd136a40cd4a31b3c64 /block | |
| parent | 5919482e222908d40279a616b1fe6400549e32b4 (diff) | |
block: put the same page when adding it to bio
When the added page is merged to last same page in bio_add_pc_page(),
the user may need to put this page for avoiding page leak.
bio_map_user_iov() needs this kind of handling, and now it deals with
it by itself in hack style.
Moves the handling of put page into __bio_add_pc_page(), so
bio_map_user_iov() may be simplified a bit, and maybe more users
can benefit from this change.
Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/bio.c | 28 |
1 files changed, 16 insertions, 12 deletions
diff --git a/block/bio.c b/block/bio.c index 7ab7060a0e6c..26853e072cd7 100644 --- a/block/bio.c +++ b/block/bio.c @@ -666,12 +666,13 @@ static inline bool page_is_mergeable(const struct bio_vec *bv, } /** - * bio_add_pc_page - attempt to add page to passthrough bio + * __bio_add_pc_page - attempt to add page to passthrough bio * @q: the target queue * @bio: destination bio * @page: page to add * @len: vec entry length * @offset: vec entry offset + * @put_same_page: put the page if it is same with last added page * * Attempt to add a page to the bio_vec maplist. This can fail for a * number of reasons, such as the bio being full or target block device @@ -680,8 +681,9 @@ static inline bool page_is_mergeable(const struct bio_vec *bv, * * This should only be used by passthrough bios. */ -int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page - *page, unsigned int len, unsigned int offset) +int __bio_add_pc_page(struct request_queue *q, struct bio *bio, + struct page *page, unsigned int len, unsigned int offset, + bool put_same_page) { int retried_segments = 0; struct bio_vec *bvec; @@ -705,6 +707,8 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page if (page == bvec->bv_page && offset == bvec->bv_offset + bvec->bv_len) { + if (put_same_page) + put_page(page); bvec->bv_len += len; bio->bi_iter.bi_size += len; goto done; @@ -763,6 +767,13 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page blk_recount_segments(q, bio); return 0; } +EXPORT_SYMBOL(__bio_add_pc_page); + +int bio_add_pc_page(struct request_queue *q, struct bio *bio, + struct page *page, unsigned int len, unsigned int offset) +{ + return __bio_add_pc_page(q, bio, page, len, offset, false); +} EXPORT_SYMBOL(bio_add_pc_page); /** @@ -1397,21 +1408,14 @@ struct bio *bio_map_user_iov(struct request_queue *q, for (j = 0; j < npages; j++) { struct page *page = pages[j]; unsigned int n = PAGE_SIZE - offs; - unsigned short prev_bi_vcnt = bio->bi_vcnt; if (n > bytes) n = bytes; - if (!bio_add_pc_page(q, bio, page, n, offs)) + if (!__bio_add_pc_page(q, bio, page, n, offs, + true)) break; - /* - * check if vector was merged with previous - * drop page reference if needed - */ - if (bio->bi_vcnt == prev_bi_vcnt) - put_page(page); - added += n; bytes -= n; offs = 0; |