Re: [PATCH] md: do not use ++ in rcu_dereference() argument
From: Arnd Bergmann <arnd@arndb.de>
Date: 2010-09-06 20:11:14
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On Sunday 05 September 2010 20:32:18 Kulikov Vasiliy wrote:
From: Vasiliy Kulikov <redacted> rcu_dereference() is macro, so it might use its argument twice. Argument must not has side effects. It was found by compiler warning: drivers/md/raid1.c: In function ‘read_balance’: drivers/md/raid1.c:445: warning: operation on ‘new_disk’ may be undefined
I think the rcu_dereference macro should really not evaluate its argument twice, and I don't see where it does. As a general rule, we try to write macros in Linux such that they behave like functions and don't have surprising side-effects. Which kernel and gcc version do you see the warning with? Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html