ublk: split out ublk_copy_user_bvec() helper

Factor a helper function ublk_copy_user_bvec() out of
ublk_copy_user_pages(). It will be used for copying integrity data too.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index fc7de2985a20565609a782770af2a433d9e7ceb0..8f0d005a64e2335c6b0c05c0ce1868b960cae6e1 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -993,6 +993,35 @@ static const struct block_device_operations ub_fops = {
        .report_zones = ublk_report_zones,
 };
 
+static bool ublk_copy_user_bvec(const struct bio_vec *bv, unsigned *offset,
+                               struct iov_iter *uiter, int dir, size_t *done)
+{
+       unsigned len;
+       void *bv_buf;
+       size_t copied;
+
+       if (*offset >= bv->bv_len) {
+               *offset -= bv->bv_len;
+               return true;
+       }
+
+       len = bv->bv_len - *offset;
+       bv_buf = kmap_local_page(bv->bv_page) + bv->bv_offset + *offset;
+       if (dir == ITER_DEST)
+               copied = copy_to_iter(bv_buf, len, uiter);
+       else
+               copied = copy_from_iter(bv_buf, len, uiter);
+
+       kunmap_local(bv_buf);
+
+       *done += copied;
+       if (copied < len)
+               return false;
+
+       *offset = 0;
+       return true;
+}
+
 /*
  * Copy data between request pages and io_iter, and 'offset'
  * is the start point of linear offset of request.
@@ -1005,29 +1034,8 @@ static size_t ublk_copy_user_pages(const struct request *req,
        size_t done = 0;
 
        rq_for_each_segment(bv, req, iter) {
-               unsigned len;
-               void *bv_buf;
-               size_t copied;
-
-               if (offset >= bv.bv_len) {
-                       offset -= bv.bv_len;
-                       continue;
-               }
-
-               len = bv.bv_len - offset;
-               bv_buf = kmap_local_page(bv.bv_page) + bv.bv_offset + offset;
-               if (dir == ITER_DEST)
-                       copied = copy_to_iter(bv_buf, len, uiter);
-               else
-                       copied = copy_from_iter(bv_buf, len, uiter);
-
-               kunmap_local(bv_buf);
-
-               done += copied;
-               if (copied < len)
+               if (!ublk_copy_user_bvec(&bv, &offset, uiter, dir, &done))
                        break;
-
-               offset = 0;
        }
        return done;
 }