[PATCH v2 13/16] rcu: Introduce 2 arg kvfree_rcu() interface

Uladzislau Rezki (Sony)
2020-05-25T21:48:35Z

kvmalloc() can allocate two types of objects: SLAB backed
and vmalloc backed. How it behaves depends on requested
object's size and memory pressure.

Add a kvfree_rcu() interface that can free memory allocated
via kvmalloc(). It is a simple alias to kfree_rcu() which
can now handle either type of object.

<snip>
struct test_kvfree_rcu {
struct rcu_head rcu;
unsigned char array[100];
};

struct test_kvfree_rcu *p;

p = kvmalloc(10 * PAGE_SIZE);
if (p)
kvfree_rcu(p, rcu);
<snip>

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
include/linux/rcupdate.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index b344fc800a9b..51b26ab02878 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -875,6 +875,15 @@ do { \
__kvfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
} while (0)

+/**
+ * kvfree_rcu() - kvfree an object after a grace period.
+ * @ptr: pointer to kvfree
+ * @rhf: the name of the struct rcu_head within the type of @ptr.
+ *
+ * Same as kfree_rcu(), just simple alias.
+ */
+#define kvfree_rcu(ptr, rhf) kfree_rcu(ptr, rhf)
+
/*
* Place this after a lock-acquisition primitive to guarantee that
* an UNLOCK+LOCK pair acts as a full barrier. This guarantee applies
--
2.20.1