This is a note to let you know that I've just added the patch titled
kref: add kref_test_and_get
to the 2.6.37-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kref-add-kref_test_and_get.patch
and it can be found in the queue-2.6.37 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From e4a683c899cd5a49f8d684a054c95bd115a0c005 Mon Sep 17 00:00:00 2001
From: Jerome Marchand <[email protected]>
Date: Wed, 5 Jan 2011 16:57:37 +0100
Subject: kref: add kref_test_and_get
From: Jerome Marchand <[email protected]>
commit e4a683c899cd5a49f8d684a054c95bd115a0c005 upstream.
Add kref_test_and_get() function, which atomically add a reference only if
refcount is not zero. This prevent to add a reference to an object that is
already being removed.
Signed-off-by: Jerome Marchand <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/kref.h | 1 +
lib/kref.c | 12 ++++++++++++
2 files changed, 13 insertions(+)
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -23,6 +23,7 @@ struct kref {
void kref_init(struct kref *kref);
void kref_get(struct kref *kref);
+int kref_test_and_get(struct kref *kref);
int kref_put(struct kref *kref, void (*release) (struct kref *kref));
#endif /* _KREF_H_ */
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -37,6 +37,18 @@ void kref_get(struct kref *kref)
}
/**
+ * kref_test_and_get - increment refcount for object only if refcount is not
+ * zero.
+ * @kref: object.
+ *
+ * Return non-zero if the refcount was incremented, 0 otherwise
+ */
+int kref_test_and_get(struct kref *kref)
+{
+ return atomic_inc_not_zero(&kref->refcount);
+}
+
+/**
* kref_put - decrement refcount for object.
* @kref: object.
* @release: pointer to the function that will clean up the object when the
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.37/kref-add-kref_test_and_get.patch
queue-2.6.37/block-fix-accounting-bug-on-cross-partition-merges.patch
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