block: use iter_ubuf for single range

This is more efficient than iter_iov.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[axboe: fold in iovec assumption fix]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-map.c b/block/blk-map.c
index 19940c9..f2135e6 100644 (file)
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -31,7 +31,8 @@ static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
                return NULL;
        memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
        bmd->iter = *data;
-       bmd->iter.iov = bmd->iov;
+       if (iter_is_iovec(data))
+               bmd->iter.iov = bmd->iov;
        return bmd;
 }
 
@@ -641,7 +642,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
                copy = true;
        else if (iov_iter_is_bvec(iter))
                map_bvec = true;
-       else if (!iter_is_iovec(iter))
+       else if (!user_backed_iter(iter))
                copy = true;
        else if (queue_virt_boundary(q))
                copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);
@@ -682,9 +683,8 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
                    struct rq_map_data *map_data, void __user *ubuf,
                    unsigned long len, gfp_t gfp_mask)
 {
-       struct iovec iov;
        struct iov_iter i;
-       int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i);
+       int ret = import_ubuf(rq_data_dir(rq), ubuf, len, &i);
 
        if (unlikely(ret < 0))
                return ret;