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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107// SPDX-License-Identifier: GPL-2.0#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);
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);
kfree_rcu(cs, rcu);}EXPORT_SYMBOL(ceph_release_string);
bool ceph_strings_empty(void){ return RB_EMPTY_ROOT(&string_tree);}