Eric Lee / smarc-fsl-linux-kernel

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net/ceph/string_table.c 2.2 KB
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b24413180   Greg Kroah-Hartman   License cleanup: ... 
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  // SPDX-License-Identifier: GPL-2.0
51e927379   Yan, Zheng   libceph: introduc... 
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  #include <linux/slab.h>
  #include <linux/gfp.h>
  #include <linux/string.h>
  #include <linux/spinlock.h>
  #include <linux/ceph/string_table.h>
  
  static DEFINE_SPINLOCK(string_tree_lock);
  static struct rb_root string_tree = RB_ROOT;
  
  struct ceph_string *ceph_find_or_create_string(const char* str, size_t len)
  {
  	struct ceph_string *cs, *exist;
  	struct rb_node **p, *parent;
  	int ret;
  
  	exist = NULL;
  	spin_lock(&string_tree_lock);
  	p = &string_tree.rb_node;
  	while (*p) {
  		exist = rb_entry(*p, struct ceph_string, node);
  		ret = ceph_compare_string(exist, str, len);
  		if (ret > 0)
  			p = &(*p)->rb_left;
  		else if (ret < 0)
  			p = &(*p)->rb_right;
  		else
  			break;
  		exist = NULL;
  	}
  	if (exist && !kref_get_unless_zero(&exist->kref)) {
  		rb_erase(&exist->node, &string_tree);
  		RB_CLEAR_NODE(&exist->node);
  		exist = NULL;
  	}
  	spin_unlock(&string_tree_lock);
  	if (exist)
  		return exist;
  
  	cs = kmalloc(sizeof(*cs) + len + 1, GFP_NOFS);
  	if (!cs)
  		return NULL;
  
  	kref_init(&cs->kref);
  	cs->len = len;
  	memcpy(cs->str, str, len);
  	cs->str[len] = 0;
  
  retry:
  	exist = NULL;
  	parent = NULL;
  	p = &string_tree.rb_node;
  	spin_lock(&string_tree_lock);
  	while (*p) {
  		parent = *p;
  		exist = rb_entry(*p, struct ceph_string, node);
  		ret = ceph_compare_string(exist, str, len);
  		if (ret > 0)
  			p = &(*p)->rb_left;
  		else if (ret < 0)
  			p = &(*p)->rb_right;
  		else
  			break;
  		exist = NULL;
  	}
  	ret = 0;
  	if (!exist) {
  		rb_link_node(&cs->node, parent, p);
  		rb_insert_color(&cs->node, &string_tree);
  	} else if (!kref_get_unless_zero(&exist->kref)) {
  		rb_erase(&exist->node, &string_tree);
  		RB_CLEAR_NODE(&exist->node);
  		ret = -EAGAIN;
  	}
  	spin_unlock(&string_tree_lock);
  	if (ret == -EAGAIN)
  		goto retry;
  
  	if (exist) {
  		kfree(cs);
  		cs = exist;
  	}
  
  	return cs;
  }
  EXPORT_SYMBOL(ceph_find_or_create_string);
51e927379   Yan, Zheng   libceph: introduc... 
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  void ceph_release_string(struct kref *ref)
  {
  	struct ceph_string *cs = container_of(ref, struct ceph_string, kref);
  
  	spin_lock(&string_tree_lock);
  	if (!RB_EMPTY_NODE(&cs->node)) {
  		rb_erase(&cs->node, &string_tree);
  		RB_CLEAR_NODE(&cs->node);
  	}
  	spin_unlock(&string_tree_lock);
864364a29   Wei Yongjun   libceph: using kf... 
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  	kfree_rcu(cs, rcu);
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  }
  EXPORT_SYMBOL(ceph_release_string);
  
  bool ceph_strings_empty(void)
  {
  	return RB_EMPTY_ROOT(&string_tree);
  }