linux-kernel - [PATCH v7 15/21] testing/radix-tree/maple: Hack around kfree

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Message-Id: <20250903-slub-percpu-caches-v7-15-71c114cdefef@suse.cz>
Date: Wed, 03 Sep 2025 14:59:57 +0200
From: Vlastimil Babka <vbabka@...e.cz>
To: Suren Baghdasaryan <surenb@...gle.com>, 
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, 
 Christoph Lameter <cl@...two.org>, David Rientjes <rientjes@...gle.com>
Cc: Roman Gushchin <roman.gushchin@...ux.dev>, 
 Harry Yoo <harry.yoo@...cle.com>, Uladzislau Rezki <urezki@...il.com>, 
 Sidhartha Kumar <sidhartha.kumar@...cle.com>, linux-mm@...ck.org, 
 linux-kernel@...r.kernel.org, rcu@...r.kernel.org, 
 maple-tree@...ts.infradead.org, vbabka@...e.cz, 
 Pedro Falcato <pfalcato@...e.de>
Subject: [PATCH v7 15/21] testing/radix-tree/maple: Hack around kfree_rcu
 not existing

From: "Liam R. Howlett" <Liam.Howlett@...cle.com>

liburcu doesn't have kfree_rcu (or anything similar). Despite that, we
can hack around it in a trivial fashion, by adding a wrapper.

The wrapper only works for maple_nodes because we cannot get the
kmem_cache pointer any other way in the test code.

Link: https://lore.kernel.org/all/20250812162124.59417-1-pfalcato@suse.de/
Suggested-by: Pedro Falcato <pfalcato@...e.de>
Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
---
 tools/testing/shared/maple-shared.h | 11 +++++++++++
 tools/testing/shared/maple-shim.c   |  6 ++++++
 2 files changed, 17 insertions(+)

diff --git a/tools/testing/shared/maple-shared.h b/tools/testing/shared/maple-shared.h
index dc4d30f3860b9bd23b4177c7d7926ac686887815..2a1e9a8594a2834326cd9374738b2a2c7c3f9f7c 100644
--- a/tools/testing/shared/maple-shared.h
+++ b/tools/testing/shared/maple-shared.h
@@ -10,4 +10,15 @@
 #include <time.h>
 #include "linux/init.h"

+void maple_rcu_cb(struct rcu_head *head);
+#define rcu_cb		maple_rcu_cb
+
+#define kfree_rcu(_struct, _memb)		\
+do {                                            \
+    typeof(_struct) _p_struct = (_struct);      \
+                                                \
+    call_rcu(&((_p_struct)->_memb), rcu_cb);    \
+} while(0);
+
+
 #endif /* __MAPLE_SHARED_H__ */
diff --git a/tools/testing/shared/maple-shim.c b/tools/testing/shared/maple-shim.c
index 9d7b743415660305416e972fa75b56824211b0eb..16252ee616c0489c80490ff25b8d255427bf9fdc 100644
--- a/tools/testing/shared/maple-shim.c
+++ b/tools/testing/shared/maple-shim.c
@@ -6,3 +6,9 @@
 #include <linux/slab.h>

 #include "../../../lib/maple_tree.c"
+
+void maple_rcu_cb(struct rcu_head *head) {
+	struct maple_node *node = container_of(head, struct maple_node, rcu);
+
+	kmem_cache_free(maple_node_cache, node);
+}

-- 
2.51.0