[PATCH review 08/11] mnt: Remove redundant NULL tests in namespace_unlock

Eric W. Biederman ebiederm at xmission.com
Mon Jan 5 20:46:24 UTC 2015

mntget, mntput, dput and pathput all test their arguments to see if
they are NULL before taking any action, so testing for NULL in
namespace_unlock is redundant.

Remove the redundant checks making namespace_unlock a little
shorter and easier to read.

This also makes it possible for mnt_ex_mountpoint.mnt to be NULL
allowing putting a dentry without a mount.  This is will be needed
in __detach_mounts when detaching already unmounted children,
as part of the fix for MNT_DETACH on MNT_LOCKED mounts.

Cc: stable at vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm at xmission.com>
 fs/namespace.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 9fae55f2242e..3769dbd040c1 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1312,8 +1312,7 @@ static void namespace_unlock(void)
 	/* undo decrements we'd done in umount_tree() */
 	list_for_each_entry(mnt, &head, mnt_list)
-		if (mnt->mnt_ex_mountpoint.mnt)
-			mntget(mnt->mnt_ex_mountpoint.mnt);
+		mntget(mnt->mnt_ex_mountpoint.mnt);
@@ -1322,8 +1321,7 @@ static void namespace_unlock(void)
 	while (!list_empty(&head)) {
 		mnt = list_first_entry(&head, struct mount, mnt_list);
-		if (mnt->mnt_ex_mountpoint.mnt)
-			path_put(&mnt->mnt_ex_mountpoint);
+		path_put(&mnt->mnt_ex_mountpoint);

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