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Message-Id: <11777000814075-git-send-email-gregkh@suse.de>
Date: Fri, 27 Apr 2007 11:53:26 -0700
From: Greg Kroah-Hartman <gregkh@...e.de>
To: linux-kernel@...r.kernel.org
Cc: Oliver Neukum <oneukum@...e.de>,
Greg Kroah-Hartman <gregkh@...e.de>
Subject: [PATCH 12/46] kref: fix CPU ordering with respect to krefs
From: Oliver Neukum <oneukum@...e.de>
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.
Signed-off-by: Oliver Neukum <oneukum@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
---
lib/kref.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/lib/kref.c b/lib/kref.c
index 0d07cc3..a6dc3ec 100644
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -21,6 +21,7 @@
void kref_init(struct kref *kref)
{
atomic_set(&kref->refcount,1);
+ smp_mb();
}
/**
@@ -31,6 +32,7 @@ void kref_get(struct kref *kref)
{
WARN_ON(!atomic_read(&kref->refcount));
atomic_inc(&kref->refcount);
+ smp_mb__after_atomic_inc();
}
/**
--
1.5.1.2
-
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