Use new QEMU_IOVEC_INIT_BUF() instead of
qemu_iovec_init_external( ... , 1), which simplifies the code.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/stream.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/block/stream.c b/block/stream.c
index 7a49ac0992..e14579ff80 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -41,14 +41,9 @@ static int coroutine_fn stream_populate(BlockBackend *blk,
                                         int64_t offset, uint64_t bytes,
                                         void *buf)
 {
-    struct iovec iov = {
-        .iov_base = buf,
-        .iov_len  = bytes,
-    };
-    QEMUIOVector qiov;
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
 
     assert(bytes < SIZE_MAX);
-    qemu_iovec_init_external(&qiov, &iov, 1);
 
     /* Copy-on-read the unallocated clusters */
     return blk_co_preadv(blk, offset, qiov.size, &qiov, BDRV_REQ_COPY_ON_READ);
-- 
2.18.0