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SubjectRe: Warnings from sched_debug.c

* Meelis Roos <mroos@linux.ee> wrote:

> This happens on sparc64 with 2.6.24-rc6 (gcc-4.2):
>
> CC kernel/sched.o
> In file included from kernel/sched.c:879:
> kernel/sched_debug.c: In function 'nsec_high':
> kernel/sched_debug.c:38: warning: comparison of distinct pointer types lacks a cast
> kernel/sched_debug.c:41: warning: comparison of distinct pointer types lacks a cast
> kernel/sched_debug.c: In function 'nsec_low':
> kernel/sched_debug.c:51: warning: comparison of distinct pointer types lacks a cast

it should be harmless. Does the patch below fix the warnings?

Ingo

-------------->
Subject: sched: fix gcc warnings
From: Ingo Molnar <mingo@elte.hu>
Meelis Roos reported these warnings on sparc64:

CC kernel/sched.o
In file included from kernel/sched.c:879:
kernel/sched_debug.c: In function 'nsec_high':
kernel/sched_debug.c:38: warning: comparison of distinct pointer types lacks a cast

the debug check in do_div() is over-eager here, because the long long
is always positive in these places. Mark this by casting them to
unsigned long long.

no change in code output:

text data bss dec hex filename
51471 6582 376 58429 e43d sched.o.before
51471 6582 376 58429 e43d sched.o.after

md5:
7f7729c111f185bf3ccea4d542abc049 sched.o.before.asm
7f7729c111f185bf3ccea4d542abc049 sched.o.after.asm

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/sched_debug.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
Index: linux/kernel/sched_debug.c
===================================================================
--- linux.orig/kernel/sched_debug.c
+++ linux/kernel/sched_debug.c
@@ -31,9 +31,9 @@
/*
* Ease the printing of nsec fields:
*/
-static long long nsec_high(long long nsec)
+static long long nsec_high(unsigned long long nsec)
{
- if (nsec < 0) {
+ if ((long long)nsec < 0) {
nsec = -nsec;
do_div(nsec, 1000000);
return -nsec;
@@ -43,9 +43,9 @@ static long long nsec_high(long long nse
return nsec;
}

-static unsigned long nsec_low(long long nsec)
+static unsigned long nsec_low(unsigned long long nsec)
{
- if (nsec < 0)
+ if ((long long)nsec < 0)
nsec = -nsec;

return do_div(nsec, 1000000);

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