vdpa: potential uninitialized return in vhost_vdpa_va_map()

mainline inclusion
from mainline-v5.15-rc4
commit be9c6bad
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5WXCZ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=be9c6bad9b46451ba5bb8d366c51e2475f374981

----------------------------------------------------------------------

The concern here is that "ret" can be uninitialized if we hit the
"goto next" condition on every iteration through the loop.

Fixes: 41ba1b5f9d4b ("vdpa: Support transferring virtual addressing during DMA mapping")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20210907073253.GB18254@kiliSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NXie Yongji <xieyongji@bytedance.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: NPengyuan Zhao <zhaopengyuan@hisilicon.com>

drivers/vhost/vdpa.c

@@ -673,7 +673,7 @@ static int vhost_vdpa_va_map(struct vhost_vdpa *v,
 	u64 offset, map_size, map_iova = iova;
 	struct vdpa_map_file *map_file;
 	struct vm_area_struct *vma;
-	int ret;
+	int ret = 0;
 
 	mmap_read_lock(dev->mm);