From: Oliver Neukum <oneukum@suse.de>
To: Greg KH <gregkh@suse.de>, linux-kernel@vger.kernel.org
Subject: CPU ordering with respect to krefs
Date: Mon, 2 Apr 2007 14:47:59 +0200 [thread overview]
Message-ID: <200704021447.59476.oneukum@suse.de> (raw)
Hi,
some atomic operations are only atomic, not ordered. Thus a CPU is allowed
to reorder memory references to an object to before the reference is
obtained. This fixes it.
Regards
Oliver
Signed-off-by: Oliver Neukum <oneukum@suse.de>
------
--- a/lib/kref.c 2007-04-02 14:40:40.000000000 +0200
+++ b/lib/kref.c 2007-04-02 14:40:50.000000000 +0200
@@ -21,6 +21,7 @@
void kref_init(struct kref *kref)
{
atomic_set(&kref->refcount,1);
+ smp_mb();
}
/**
@@ -31,6 +32,7 @@
{
WARN_ON(!atomic_read(&kref->refcount));
atomic_inc(&kref->refcount);
+ smp_mb__after_atomic_inc();
}
/**
next reply other threads:[~2007-04-02 13:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-02 12:47 Oliver Neukum [this message]
2007-04-02 14:33 ` CPU ordering with respect to krefs Eric Dumazet
2007-04-12 6:27 ` Greg KH
2007-04-17 5:44 ` Oliver Neukum
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