+ testing-radix-tree-maple-hack-around-kfree_rcu-not-existing.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: testing/radix-tree/maple: hack around kfree_rcu not existing
has been added to the -mm mm-new branch.  Its filename is
     testing-radix-tree-maple-hack-around-kfree_rcu-not-existing.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/testing-radix-tree-maple-hack-around-kfree_rcu-not-existing.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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patches, and acceptance into mm-new is a notification for others take
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------------------------------------------------------
From: Pedro Falcato <pfalcato@suse.de>
Subject: testing/radix-tree/maple: hack around kfree_rcu not existing
Date: Fri, 18 Jul 2025 18:21:37 +0100

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

This wrapper only works for maple_nodes, and not anything else (due to us
not being able to know rcu_head offsets in any way), and thus we take
advantage of the type checking to avoid future silent breakage.

Link: https://lkml.kernel.org/r/20250718172138.103116-2-pfalcato@suse.de
Signed-off-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/radix-tree/maple.c |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

--- a/tools/testing/radix-tree/maple.c~testing-radix-tree-maple-hack-around-kfree_rcu-not-existing
+++ a/tools/testing/radix-tree/maple.c
@@ -23,6 +23,23 @@
 #define MODULE_LICENSE(x)
 #define dump_stack()	assert(0)
 
+
+#include <linux/maple_tree.h>
+
+static void free_node(struct rcu_head *head)
+{
+	struct maple_node *node = container_of(head, struct maple_node, rcu);
+
+	free(node);
+}
+
+static void kfree_rcu_node(struct maple_node *node)
+{
+	call_rcu(&node->rcu, free_node);
+}
+
+#define kfree_rcu(ptr, memb) kfree_rcu_node(ptr)
+
 #include "../../../lib/maple_tree.c"
 #include "../../../lib/test_maple_tree.c"
 
_

Patches currently in -mm which might be from pfalcato@suse.de are

maple_tree-use-kfree_rcu-in-ma_free_rcu.patch
testing-radix-tree-maple-hack-around-kfree_rcu-not-existing.patch