hugetlb: remove use of list iterator variable after loop

In preparation to limit the scope of the list iterator to the list
traversal loop, use a dedicated pointer to iterate through the list [1].

Before hugetlb_resv_map_add() was expecting a file_region struct, but in
case the list iterator in add_reservation_in_range() did not exit early,
the variable passed in, is not actually a valid structure.

In such a case 'rg' is computed on the head element of the list and
represents an out-of-bounds pointer.  This still remains safe *iff* you
only use the link member (as it is done in hugetlb_resv_map_add()).

To avoid the type-confusion altogether and limit the list iterator to the
loop, only a list_head pointer is kept to pass to hugetlb_resv_map_add().

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Jakob Koschel <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: "Brian Johannesmeyer" <[email protected]>
Cc: Cristiano Giuffrida <[email protected]>
Cc: "Bos, H.J." <[email protected]>
Cc: Jakob Koschel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions