block: introduce struct rq_map_data to use reserved pages

This patch introduces struct rq_map_data to enable bio_copy_use_iov()
use reserved pages.

Currently, bio_copy_user_iov allocates bounce pages but
drivers/scsi/sg.c wants to allocate pages by itself and use
them. struct rq_map_data can be used to pass allocated pages to
bio_copy_user_iov.

The current users of bio_copy_user_iov simply passes NULL (they don't
want to use pre-allocated pages).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Douglas Gilbert <dougg@torque.net>
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, 1 insertions, 1 deletions

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index e861d24a6d32..d47f2f80accd 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2097,7 +2097,7 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
 
                 len = nr * CD_FRAMESIZE_RAW;
 
-                ret = blk_rq_map_user(q, rq, ubuf, len, GFP_KERNEL);
+                ret = blk_rq_map_user(q, rq, NULL, ubuf, len, GFP_KERNEL);
                 if (ret)
                         break;