block: convert bio_copy_user to bio_copy_user_iov

This patch enables bio_copy_user to take struct sg_iovec (renamed
bio_copy_user_iov). bio_copy_user uses bio_copy_user_iov internally as
bio_map_user uses bio_map_user_iov.

The major changes are:

- adds sg_iovec array to struct bio_map_data

- adds __bio_copy_iov that copy data between bio and
sg_iovec. bio_copy_user_iov and bio_uncopy_user use it.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 4c59bdccd3ee..d259690863fb 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -327,6 +327,8 @@ extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 extern void bio_set_pages_dirty(struct bio *bio);
 extern void bio_check_pages_dirty(struct bio *bio);
 extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
+extern struct bio *bio_copy_user_iov(struct request_queue *, struct sg_iovec *,
+                                     int, int);
 extern int bio_uncopy_user(struct bio *);
 void zero_fill_bio(struct bio *bio);