From: Al Viro <viro@ftp.linux.org.uk>
To: davem@davemloft.net
Cc: Linus Torvalds <torvalds@osdl.org>, linux-kernel@vger.kernel.org
Subject: [PATCH] highest_possible_processor_id() has to be a macro
Date: Sun, 16 Oct 2005 00:51:12 +0100 [thread overview]
Message-ID: <20051015235112.GA7992@ftp.linux.org.uk> (raw)
... otherwise, things like alpha and sparc64 break and break
badly. They define cpu_possible_map to something else in smp.h
*AFTER* having included cpumask.h.
If that puppy is a macro, expansion will happen at the actual
caller, when we'd already seen #define cpu_possible_map ... and we will
get the right thing used.
As an inline helper it will be tokenized before we get to that
define and that's it; no matter what we define later, it won't affect
anything. We get modules with dependency on cpu_possible_map instead
of the right symbol (phys_cpu_present_map in case of sparc64), or outright
link errors if they are built-in.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
----
diff -urN RC14-rc4-git4-base/include/linux/cpumask.h current/include/linux/cpumask.h
--- RC14-rc4-git4-base/include/linux/cpumask.h 2005-10-15 16:21:34.000000000 -0400
+++ current/include/linux/cpumask.h 2005-10-15 19:46:34.000000000 -0400
@@ -393,15 +393,13 @@
#define for_each_present_cpu(cpu) for_each_cpu_mask((cpu), cpu_present_map)
/* Find the highest possible smp_processor_id() */
-static inline unsigned int highest_possible_processor_id(void)
-{
- unsigned int cpu, highest = 0;
-
- for_each_cpu_mask(cpu, cpu_possible_map)
- highest = cpu;
-
- return highest;
-}
+#define highest_possible_processor_id() \
+({ \
+ unsigned int cpu, highest = 0; \
+ for_each_cpu_mask(cpu, cpu_possible_map) \
+ highest = cpu; \
+ highest; \
+})
#endif /* __LINUX_CPUMASK_H */
next reply other threads:[~2005-10-15 23:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-15 23:51 Al Viro [this message]
2005-10-16 7:16 ` [PATCH] highest_possible_processor_id() has to be a macro David S. Miller
2005-10-16 7:43 ` Herbert Xu
2005-10-16 7:46 ` Al Viro
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