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/[email protected]
Fixes: b7f0554 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
Signed-off-by: Christophe JAILLET <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: David Sterba <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: tititiou36

mm/frame_vector.c

@@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
 	 * 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;