From 818827669d85b84241696ffef2de485db46b0b5e Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Tue, 2 Sep 2008 16:20:19 +0900 Subject: 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 Signed-off-by: Jens Axboe --- fs/bio.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'fs/bio.c') diff --git a/fs/bio.c b/fs/bio.c index 9d68ddb89b71..355302985e22 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -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; -- cgit v1.2.3