[RFC][PATCH 0/5] Fixes for abs() usage on 64bit values

[John Stultz]

As noted in include/linux/kernel.h:
 "abs() should not be used for 64-bit types (s64, u64, long long)
 - use abs64() for those."

Unfortunately, there are quite a number of places where abs()
was used w/ 64bit values in the kernel, and the results are
then silently capped to 32-bit values on 32-bit systems.

This series tries to address the problematic sites I found,
and then introduces a patch which modifies abs() so that the
build will fail if a 64-bit type is passed to it on a 32-bit
machine.

I'm sure there are additional sites that will need fixing,
but hopefully this will make them easy to find.

Comments and feedback would be greatly appreciated!

Thanks
-john

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>


John Stultz (5):
  clocksource: Fix abs() usage w/ 64bit values
  time: Fix abs() usage with 64-bit values.
  ext4: Fix abs() usage in  ext4_mb_check_group_pa
  percpu: Fix abs() usage in percpu_counter_compare()
  abs(): Provide build error on passing 64bit value to abs()

 fs/ext4/mballoc.c         | 4 ++--
 include/linux/kernel.h    | 3 +++
 kernel/time/clocksource.c | 2 +-
 kernel/time/timekeeping.c | 2 +-
 lib/percpu_counter.c      | 2 +-
 5 files changed, 8 insertions(+), 5 deletions(-)

-- 
1.9.1

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