tree c846b1c8074d29b9fc02ef3eeda98631dfd6ee94
parent aa9c0e07bb90589186f3b5a0ca97660c2cb50806
author Al Viro <viro@zeniv.linux.org.uk> 1322094383 -0500
committer Al Viro <viro@zeniv.linux.org.uk> 1325649156 -0500

vfs: new internal helper: mnt_has_parent(mnt)

vfsmounts have ->mnt_parent pointing either to a different vfsmount
or to itself; it's never NULL and termination condition in loops
traversing the tree towards root is mnt == mnt->mnt_parent.  At least
one place (see the next patch) is confused about what's going on;
let's add an explicit helper checking it right way and use it in
all places where we need it.  Not that there had been too many,
but...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>