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[SCSI] block: fix the partial mappings with struct rq_map_data

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This fixes bio_copy_user_iov to properly handle the partial mappings
with struct rq_map_data (which only sg uses for now but st and osst
will shortly). It adds the offset member to struct rq_map_data and
changes blk_rq_map_user to update it so that bio_copy_user_iov can add
an appropriate page frame via bio_add_pc_page().

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
FUJITA Tomonori 2008-12-18 14:49:37 +09:00 committed by James Bottomley
parent e623ddb4e9
commit 56c451f4b5
4 changed files with 14 additions and 3 deletions
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3
block/blk-map.c
View File

@ -150,6 +150,9 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
bio = rq->bio;
bytes_read += ret;
ubuf += ret;
if (map_data)
map_data->offset += ret;
}
if (!bio_flagged(bio, BIO_USER_MAPPED))

1
drivers/scsi/sg.c
View File

@ -1669,6 +1669,7 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd)
md->pages = req_schp->pages;
md->page_order = req_schp->page_order;
md->nr_entries = req_schp->k_use_sg;
md->offset = 0;
}
if (iov_count)

12
fs/bio.c
View File

@ -788,6 +788,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
int i, ret;
int nr_pages = 0;
unsigned int len = 0;
unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
for (i = 0; i < iov_count; i++) {
unsigned long uaddr;
@ -814,12 +815,16 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
bio->bi_rw |= (!write_to_vm << BIO_RW);
ret = 0;
i = 0;
if (map_data)
if (map_data) {
nr_pages = 1 << map_data->page_order;
i = map_data->offset / PAGE_SIZE;
}
while (len) {
unsigned int bytes = PAGE_SIZE;
bytes -= offset;
if (bytes > len)
bytes = len;
@ -841,10 +846,11 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
}
}
if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
break;
len -= bytes;
offset = 0;
}
if (ret)

1
include/linux/blkdev.h
View File

@ -690,6 +690,7 @@ struct rq_map_data {
struct page **pages;
int page_order;
int nr_entries;
unsigned long offset;
};
struct req_iterator {