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| author | FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2008-09-02 16:20:19 +0900 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 08:56:11 +0200 |
| commit | 818827669d85b84241696ffef2de485db46b0b5e (patch) | |
| tree | 694d09728733e65d604bf3e1f13679db73fc1d9a /fs/bio.c | |
| parent | 839e96afba87117befd39cf4e43f156edc8047a7 (diff) | |
| download | linux-818827669d85b84241696ffef2de485db46b0b5e.tar.gz linux-818827669d85b84241696ffef2de485db46b0b5e.tar.bz2 linux-818827669d85b84241696ffef2de485db46b0b5e.zip | |
block: make blk_rq_map_user take a NULL user-space buffer
This patch changes blk_rq_map_user to accept a NULL user-space buffer
with a READ command if rq_map_data is not NULL. Thus a caller can pass
page frames to lk_rq_map_user to just set up a request and bios with
page frames propely. bio_uncopy_user (called via blk_rq_unmap_user)
doesn't copy data to user space with such request.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'fs/bio.c')
| -rw-r--r-- | fs/bio.c | 8 |
1 files changed, 4 insertions, 4 deletions
@@ -547,11 +547,11 @@ static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs, int bio_uncopy_user(struct bio *bio) { struct bio_map_data *bmd = bio->bi_private; - int ret; - - ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs, bmd->nr_sgvecs, 1, - bmd->is_our_pages); + int ret = 0; + if (!bio_flagged(bio, BIO_NULL_MAPPED)) + ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs, + bmd->nr_sgvecs, 1, bmd->is_our_pages); bio_free_map_data(bmd); bio_put(bio); return ret; |