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authorPaul E. McKenney <paulmck@linux.ibm.com>2019-04-09 07:48:18 -0700
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-05-28 09:02:57 -0700
commit12edff045bc6dd3ab1565cc02fa4841803c2a633 (patch)
treefd280d56ab640d856ac77c75060d62ea73a2daea
parent3ae976a7e3e87438b8439a01aeb79d4866b1c444 (diff)
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rcu: Make kfree_rcu() ignore NULL pointers
This commit makes the kfree_rcu() macro's semantics be consistent with the likes of kfree() by adding a check for NULL pointers, so that kfree_rcu(NULL, ...) is a no-op. Reported-by: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Reviewed-by: Andriy Shevchenko <andriy.shevchenko@linux.intel.com>
-rw-r--r--include/linux/rcupdate.h12
1 files changed, 8 insertions, 4 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 922bb6848813..915460ec0872 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -805,7 +805,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
/**
* kfree_rcu() - kfree an object after a grace period.
* @ptr: pointer to kfree
- * @rcu_head: the name of the struct rcu_head within the type of @ptr.
+ * @rhf: the name of the struct rcu_head within the type of @ptr.
*
* Many rcu callbacks functions just call kfree() on the base structure.
* These functions are trivial, but their size adds up, and furthermore
@@ -828,9 +828,13 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* The BUILD_BUG_ON check must not involve any function calls, hence the
* checks are done in macros here.
*/
-#define kfree_rcu(ptr, rcu_head) \
- __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))
-
+#define kfree_rcu(ptr, rhf) \
+do { \
+ typeof (ptr) ___p = (ptr); \
+ \
+ if (___p) \
+ __kfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
+} while (0)
/*
* Place this after a lock-acquisition primitive to guarantee that