percpu_counter: change return value and add comments
percpu_counter: change return value and add comments

The percpu_counter_*_positive() API in UP case doesn't check if return
value is positive.  Add comments to explain why we don't.  Also if count <
0, returns 0 instead of 1 for *read_positive().

[5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org: tweak comment]
Signed-off-by: Shaohua Li <cb3904095a5bc20edc93ba3dfa3e7d27d981b654@intel.com>
Acked-by: Eric Dumazet <a0baddf32b28d2f9429941ed4af2fe636e210591@gmail.com>
Cc: Tejun Heo <546b05909706652891a87f7bfe385ae147f61f91@kernel.org>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas