mm/frame_vector.c: release a semaphore in 'get_vaddr_frames()'

A semaphore is acquired before this check, so we must release it before
leaving.

Link: http://lkml.kernel.org/r/[e-mail]
Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
Signed-off-by: Christophe JAILLET <[e-mail]>
Acked-by: Michal Hocko <[e-mail]>
Cc: Dan Williams <[e-mail]>
Cc: Christian Borntraeger <[e-mail]>
Cc: David Sterba <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

mm/frame_vector.c

···
 	 * get_user_pages_longterm() and disallow it for filesystem-dax
 	 * mappings.
 	 */
-	if (vma_is_fsdax(vma))
-		return -EOPNOTSUPP;
+	if (vma_is_fsdax(vma)) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
 
 	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
 		vec->got_ref = true;