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, 2 insertions, 2 deletions

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index f49d6a11a69e..c34272a348fe 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -314,11 +314,11 @@ static int sg_io(struct file *file, struct request_queue *q,
                         goto out;
                 }
 
-                ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count,
+                ret = blk_rq_map_user_iov(q, rq, NULL, iov, hdr->iovec_count,
                                           hdr->dxfer_len, GFP_KERNEL);
                 kfree(iov);
         } else if (hdr->dxfer_len)
-                ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len,
+                ret = blk_rq_map_user(q, rq, NULL, hdr->dxferp, hdr->dxfer_len,
                                       GFP_KERNEL);
 
         if (ret)