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