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bio: fix bio_copy_kern() handling of bio->bv_len

Browse source 
The commit 68154e90c9 introduced
bio_copy_kern() to add bounce support to blk_rq_map_kern.

bio_copy_kern() uses bio->bv_len to copy data for READ commands after
the completion but it doesn't work with a request that partially
completed. SCSI always completes a PC request as a whole but seems
some don't.

This patch fixes bio_copy_kern to handle the above case. As
bio_copy_user does, bio_copy_kern uses struct bio_map_data to store
struct bio_vec.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reported-by: Nix <nix@esperi.org.uk>
Tested-by: Nix <nix@esperi.org.uk>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
FUJITA Tomonori 2008-08-25 20:36:08 +02:00 committed by Jens Axboe
parent 48fd4f93a0
commit 76029ff37f
1 changed files with 28 additions and 10 deletions
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38
fs/bio.c
View file

@ -469,20 +469,21 @@ static void bio_free_map_data(struct bio_map_data *bmd)
kfree(bmd);
}
static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count)
static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count,
gfp_t gfp_mask)
{
struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);
if (!bmd)
return NULL;
bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
if (!bmd->iovecs) {
kfree(bmd);
return NULL;
}
bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, GFP_KERNEL);
bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
if (bmd->sgvecs)
return bmd;
@ -596,7 +597,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, struct sg_iovec *iov,
len += iov[i].iov_len;
}
bmd = bio_alloc_map_data(nr_pages, iov_count);
bmd = bio_alloc_map_data(nr_pages, iov_count, GFP_KERNEL);
if (!bmd)
return ERR_PTR(-ENOMEM);
@ -942,19 +943,22 @@ static void bio_copy_kern_endio(struct bio *bio, int err)
{
struct bio_vec *bvec;
const int read = bio_data_dir(bio) == READ;
char *p = bio->bi_private;
struct bio_map_data *bmd = bio->bi_private;
int i;
char *p = bmd->sgvecs[0].iov_base;
__bio_for_each_segment(bvec, bio, i, 0) {
char *addr = page_address(bvec->bv_page);
int len = bmd->iovecs[i].bv_len;
if (read && !err)
memcpy(p, addr, bvec->bv_len);
memcpy(p, addr, len);
__free_page(bvec->bv_page);
p += bvec->bv_len;
p += len;
}
bio_free_map_data(bmd);
bio_put(bio);
}
@ -978,11 +982,21 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
const int nr_pages = end - start;
struct bio *bio;
struct bio_vec *bvec;
struct bio_map_data *bmd;
int i, ret;
struct sg_iovec iov;
iov.iov_base = data;
iov.iov_len = len;
bmd = bio_alloc_map_data(nr_pages, 1, gfp_mask);
if (!bmd)
return ERR_PTR(-ENOMEM);
ret = -ENOMEM;
bio = bio_alloc(gfp_mask, nr_pages);
if (!bio)
return ERR_PTR(-ENOMEM);
goto out_bmd;
while (len) {
struct page *page;
@ -1016,14 +1030,18 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
}
}
bio->bi_private = data;
bio->bi_private = bmd;
bio->bi_end_io = bio_copy_kern_endio;
bio_set_map_data(bmd, bio, &iov, 1);
return bio;
cleanup:
bio_for_each_segment(bvec, bio, i)
__free_page(bvec->bv_page);
bio_put(bio);
out_bmd:
bio_free_map_data(bmd);
return ERR_PTR(ret);
}