[RFC][PATCH 4/5] percpu: Fix abs() usage in percpu_counter_compare()

From: John Stultz
Date: Mon Sep 14 2015 - 21:06:30 EST


s64 values should not be used with abs(), as is one
in __percpu_counter_compare(), since it may cap the
result to 32-bits.

This patch modifies __percpu_counter_compare() to
use abs64() instead.

Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
lib/percpu_counter.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index f051d69..3d1aba9 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -203,7 +203,7 @@ int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch)

count = percpu_counter_read(fbc);
/* Check to see if rough count will be sufficient for comparison */
- if (abs(count - rhs) > (batch * num_online_cpus())) {
+ if (abs64(count - rhs) > (batch * num_online_cpus())) {
if (count > rhs)
return 1;
else
--
1.9.1

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