1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _FS_CEPH_STRING_TABLE_H 3 #define _FS_CEPH_STRING_TABLE_H 4 5 #include <linux/types.h> 6 #include <linux/kref.h> 7 #include <linux/rbtree.h> 8 #include <linux/rcupdate.h> 9 10 struct ceph_string { 11 struct kref kref; 12 union { 13 struct rb_node node; 14 struct rcu_head rcu; 15 }; 16 size_t len; 17 char str[]; 18 }; 19 20 extern void ceph_release_string(struct kref *ref); 21 extern struct ceph_string *ceph_find_or_create_string(const char *str, 22 size_t len); 23 extern bool ceph_strings_empty(void); 24 25 static inline struct ceph_string *ceph_get_string(struct ceph_string *str) 26 { 27 kref_get(&str->kref); 28 return str; 29 } 30 31 static inline void ceph_put_string(struct ceph_string *str) 32 { 33 if (!str) 34 return; 35 kref_put(&str->kref, ceph_release_string); 36 } 37 38 static inline int ceph_compare_string(struct ceph_string *cs, 39 const char* str, size_t len) 40 { 41 size_t cs_len = cs ? cs->len : 0; 42 if (cs_len != len) 43 return cs_len - len; 44 if (len == 0) 45 return 0; 46 return strncmp(cs->str, str, len); 47 } 48 49 #define ceph_try_get_string(x) \ 50 ({ \ 51 struct ceph_string *___str; \ 52 rcu_read_lock(); \ 53 for (;;) { \ 54 ___str = rcu_dereference(x); \ 55 if (!___str || \ 56 kref_get_unless_zero(&___str->kref)) \ 57 break; \ 58 } \ 59 rcu_read_unlock(); \ 60 (___str); \ 61 }) 62 63 #endif 64