File 67a5cb5f-radix-tree-purge-node-alloc-hooks.patch of Package xen.37689

# Commit 1275093a96fed45057db241b3aa6e191d9dcf596
# Date 2025-02-07 09:59:11 +0100
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
radix-tree: purge node allocation override hooks

These were needed by TMEM only, which is long gone. The Linux original
doesn't have such either. This effectively reverts one of the "Other
changes" from 8dc6738dbb3c ("Update radix-tree.[ch] from upstream Linux
to gain RCU awareness").

Positive side effect: Two cf_check go away.

While there also convert xmalloc()+memset() to xzalloc().

Requested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

--- a/xen/common/radix-tree.c
+++ b/xen/common/radix-tree.c
@@ -52,12 +52,6 @@ struct rcu_node {
 	struct rcu_head rcu_head;
 };
 
-static struct radix_tree_node *cf_check rcu_node_alloc(void *arg)
-{
-	struct rcu_node *rcu_node = xmalloc(struct rcu_node);
-	return rcu_node ? &rcu_node->node : NULL;
-}
-
 static void cf_check _rcu_node_free(struct rcu_head *head)
 {
 	struct rcu_node *rcu_node =
@@ -65,26 +59,20 @@ static void cf_check _rcu_node_free(stru
 	xfree(rcu_node);
 }
 
-static void cf_check rcu_node_free(struct radix_tree_node *node, void *arg)
-{
-	struct rcu_node *rcu_node = container_of(node, struct rcu_node, node);
-	call_rcu(&rcu_node->rcu_head, _rcu_node_free);
-}
-
 static struct radix_tree_node *radix_tree_node_alloc(
 	struct radix_tree_root *root)
 {
-	struct radix_tree_node *ret;
-	ret = root->node_alloc(root->node_alloc_free_arg);
-	if (ret)
-		memset(ret, 0, sizeof(*ret));
-	return ret;
+	struct rcu_node *rcu_node = xzalloc(struct rcu_node);
+
+	return rcu_node ? &rcu_node->node : NULL;
 }
 
 static void radix_tree_node_free(
 	struct radix_tree_root *root, struct radix_tree_node *node)
 {
-	root->node_free(node, root->node_alloc_free_arg);
+	struct rcu_node *rcu_node = container_of(node, struct rcu_node, node);
+
+	call_rcu(&rcu_node->rcu_head, _rcu_node_free);
 }
 
 /*
@@ -717,19 +705,6 @@ void radix_tree_destroy(
 void radix_tree_init(struct radix_tree_root *root)
 {
 	memset(root, 0, sizeof(*root));
-	root->node_alloc = rcu_node_alloc;
-	root->node_free = rcu_node_free;
-}
-
-void radix_tree_set_alloc_callbacks(
-	struct radix_tree_root *root,
-	radix_tree_alloc_fn_t *node_alloc,
-	radix_tree_free_fn_t *node_free,
-	void *node_alloc_free_arg)
-{
-	root->node_alloc = node_alloc;
-	root->node_free = node_free;
-	root->node_alloc_free_arg = node_alloc_free_arg;
 }
 
 static __init unsigned long __maxindex(unsigned int height)
--- a/xen/include/xen/radix-tree.h
+++ b/xen/include/xen/radix-tree.h
@@ -66,11 +66,6 @@ typedef void radix_tree_free_fn_t(struct
 struct radix_tree_root {
 	unsigned int		height;
 	struct radix_tree_node	__rcu *rnode;
-
-	/* Allow to specify custom node alloc/dealloc routines. */
-	radix_tree_alloc_fn_t *node_alloc;
-	radix_tree_free_fn_t *node_free;
-	void *node_alloc_free_arg;
 };
 
 /*
@@ -78,11 +73,6 @@ struct radix_tree_root {
  */
 
 void radix_tree_init(struct radix_tree_root *root);
-void radix_tree_set_alloc_callbacks(
-	struct radix_tree_root *root,
-	radix_tree_alloc_fn_t *node_alloc,
-	radix_tree_free_fn_t *node_free,
-	void *node_alloc_free_arg);
 
 void radix_tree_destroy(
 	struct radix_tree_root *root,