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From: John Stultz <john.stultz@linaro.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: John Stultz <john.stultz@linaro.org>,
	Dave Chinner <dchinner@redhat.com>, Tejun Heo <tj@kernel.org>,
	Ingo Molnar <mingo@kernel.org>
Subject: [RFC][PATCH 4/5] percpu: Fix abs() usage in percpu_counter_compare()
Date: Mon, 14 Sep 2015 18:05:23 -0700	[thread overview]
Message-ID: <1442279124-7309-5-git-send-email-john.stultz@linaro.org> (raw)
In-Reply-To: <1442279124-7309-1-git-send-email-john.stultz@linaro.org>

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@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 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


  parent reply	other threads:[~2015-09-15  1:06 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-15  1:05 [RFC][PATCH 0/5] Fixes for abs() usage on 64bit values John Stultz
2015-09-15  1:05 ` [RFC][PATCH 1/5] clocksource: Fix abs() usage w/ " John Stultz
2015-10-02 20:57   ` [tip:timers/urgent] " tip-bot for John Stultz
2015-09-15  1:05 ` [RFC][PATCH 2/5] time: Fix abs() usage with 64-bit values John Stultz
2015-09-15  1:05 ` [RFC][PATCH 3/5] ext4: Fix abs() usage in ext4_mb_check_group_pa John Stultz
2015-09-15  1:05 ` John Stultz [this message]
2015-09-15  1:05 ` [RFC][PATCH 5/5] abs(): Provide build error on passing 64bit value to abs() John Stultz
2015-09-15  5:22   ` Ingo Molnar
2015-09-15 23:52     ` Linus Torvalds
2015-09-16 12:57       ` [PATCH] kernel.h: make abs() work with 64-bit types Michal Nazarewicz
2015-09-18  3:12         ` John Stultz
2015-09-15  1:49 ` [RFC][PATCH 0/5] Fixes for abs() usage on 64bit values Tejun Heo
2015-09-15  3:27   ` John Stultz
2015-09-15  3:46     ` Tejun Heo
2015-09-15 12:09       ` Jeff Epler
2015-09-15 21:21       ` Andrew Morton
2015-09-15 22:54         ` Michal Nazarewicz
2015-09-15  5:20     ` Ingo Molnar
2015-09-15 23:43       ` Linus Torvalds

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