[SCSI] block: make blk_rq_map_user take a NULL user-space buffer for WRITE

The commit 818827669d85b84241696ffef2de485db46b0b5e (block: make
blk_rq_map_user take a NULL user-space buffer) extended
blk_rq_map_user to accept a NULL user-space buffer with a READ
command. It was necessary to convert sg to use the block layer mapping
API.

This patch extends blk_rq_map_user again for a WRITE command. It is
necessary to convert st and osst drivers to use the block layer
apping API.

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>

1 files changed, 7 insertions, 9 deletions

diff --git a/block/blk-map.c b/block/blk-map.c
index c7e55b23a2bc..f103729b462f 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -42,7 +42,7 @@ static int __blk_rq_unmap_user(struct bio *bio)
 
 static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
                              struct rq_map_data *map_data, void __user *ubuf,
-                             unsigned int len, int null_mapped, gfp_t gfp_mask)
+                             unsigned int len, gfp_t gfp_mask)
 {
         unsigned long uaddr;
         struct bio *bio, *orig_bio;
@@ -63,7 +63,7 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
         if (IS_ERR(bio))
                 return PTR_ERR(bio);
 
-        if (null_mapped)
+        if (map_data && map_data->null_mapped)
                 bio->bi_flags |= (1 << BIO_NULL_MAPPED);
 
         orig_bio = bio;
@@ -114,17 +114,15 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
 {
         unsigned long bytes_read = 0;
         struct bio *bio = NULL;
-        int ret, null_mapped = 0;
+        int ret;
 
         if (len > (q->max_hw_sectors << 9))
                 return -EINVAL;
         if (!len)
                 return -EINVAL;
-        if (!ubuf) {
-                if (!map_data || rq_data_dir(rq) != READ)
-                        return -EINVAL;
-                null_mapped = 1;
-        }
+
+        if (!ubuf && (!map_data || !map_data->null_mapped))
+                return -EINVAL;
 
         while (bytes_read != len) {
                 unsigned long map_len, end, start;
@@ -143,7 +141,7 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
                         map_len -= PAGE_SIZE;
 
                 ret = __blk_rq_map_user(q, rq, map_data, ubuf, map_len,
-                                        null_mapped, gfp_mask);
+                                        gfp_mask);
                 if (ret < 0)
                         goto unmap_rq;
                 if (!bio)