From: Rusty Russell <rusty@rustcorp.com.au>
To: Joel Schopp <jschopp@austin.ibm.com>,
Anton Blanchard <anton@samba.org>, Andrew Morton <akpm@osdl.org>
Cc: lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH] Fix cpu iterator on empty bitmask
Date: Wed, 28 Apr 2004 09:52:53 +1000 [thread overview]
Message-ID: <1083109972.2150.124.camel@bach> (raw)
Name: Fix cpumask iterator over empty cpu set
Status: Trivial
Can't use _ffs() without first checking for zero, and if bits beyond
NR_CPUS set it'll give bogus results. Use find_first_bit
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .26180-linux-2.6.6-rc2-bk5/include/asm-generic/cpumask_arith.h .26180-linux-2.6.6-rc2-bk5.updated/include/asm-generic/cpumask_arith.h
--- .26180-linux-2.6.6-rc2-bk5/include/asm-generic/cpumask_arith.h 2004-01-10 13:59:33.000000000 +1100
+++ .26180-linux-2.6.6-rc2-bk5.updated/include/asm-generic/cpumask_arith.h 2004-04-28 09:50:23.000000000 +1000
@@ -43,7 +43,7 @@
#define cpus_promote(map) ({ map; })
#define cpumask_of_cpu(cpu) ({ ((cpumask_t)1) << (cpu); })
-#define first_cpu(map) __ffs(map)
+#define first_cpu(map) find_first_bit(&(map), NR_CPUS)
#define next_cpu(cpu, map) find_next_bit(&(map), NR_CPUS, cpu + 1)
#endif /* __ASM_GENERIC_CPUMASK_ARITH_H */
--
Anyone who quotes me in their signature is an idiot -- Rusty Russell
next reply other threads:[~2004-04-27 23:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-27 23:52 Rusty Russell [this message]
2004-04-28 0:05 ` [PATCH] Fix cpu iterator on empty bitmask William Lee Irwin III
2004-04-28 1:22 ` Rusty Russell
2004-04-28 1:31 ` Paul Jackson
2004-04-28 1:57 ` William Lee Irwin III
2004-04-28 2:18 ` Paul Jackson
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