Commit 12edff04 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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: default avatarAndriy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
Reviewed-by: default avatarAndriy Shevchenko <andriy.shevchenko@linux.intel.com>
parent 3ae976a7

include/linux/rcupdate.h

+8 −4
Original line number Diff line number Diff line
@@ -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

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