[PATCH v2 0/2] bitmap: Fix return values to be unsigned

[Kees Cook <keescook@chromium.org>]

Hi,

As mentioned in the last patch:

Both nodemask and bitmap routines had mixed return values that provided
potentially signed results that could never happen. This was leading to
the compiler getting confusing about the range of possible return values
(it was thinking things could be negative where they could not be). Fix
all the nodemask and bitmap routines that should be returning unsigned
(or bool) values. Silences GCC 12 warnings:

 mm/swapfile.c: In function ‘setup_swap_info’:
 mm/swapfile.c:2291:47: error: array subscript -1 is below array bounds of ‘struct plist_node[]’ [-Werror=array-bounds]
  2291 |                                 p->avail_lists[i].prio = 1;
       |                                 ~~~~~~~~~~~~~~^~~
 In file included from mm/swapfile.c:16:
 ./include/linux/swap.h:292:27: note: while referencing ‘avail_lists’
   292 |         struct plist_node avail_lists[]; /*
       |                           ^~~~~~~~~~~

This splits up the patch into the bitmap and nodemask halves, and drops
a needless change to the random node helper.

I note that Alexey and Rasmus touched on this area in the past, fixing
up node ids to be unsigned:

ce0725f78a56 ("numa: make "nr_online_nodes" unsigned int")
b9726c26dc21 ("numa: make "nr_node_ids" unsigned int")
33c4fa8c6763 ("linux/nodemask.h: update bitmap wrappers to take unsigned int")

If anyone else would like to carry this, please let me know. I'm happy
to carry it in my tree.

-Kees

Kees Cook (2):
  bitmap: Fix return values to be unsigned
  nodemask: Fix return values to be unsigned

 include/linux/bitmap.h   | 14 +++++++-------
 include/linux/nodemask.h | 38 +++++++++++++++++++-------------------
 lib/bitmap.c             | 28 ++++++++++++++--------------
 lib/nodemask.c           |  2 +-
 4 files changed, 41 insertions(+), 41 deletions(-)

-- 
2.32.0