Green shading in the line number column means the source is part of the translation unit, red means it is conditionally excluded. Highlighted line numbers link to the translation unit page. Highlighted macros link to the macro page.
1: #ifndef _LINUX_RCULIST_BL_H 2: #define _LINUX_RCULIST_BL_H 3: 4: /* 5: * RCU-protected bl list version. See include/linux/list_bl.h. 6: */ 7: #include <linux/list_bl.h> 8: #include <linux/rcupdate.h> 9: 10: static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, 11: struct hlist_bl_node *n) 12: { 13: LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK); 14: LIST_BL_BUG_ON(((unsigned long)h->first & LIST_BL_LOCKMASK) != 15: LIST_BL_LOCKMASK); 16: rcu_assign_pointer(h->first, 17: (struct hlist_bl_node *)((unsigned long)n | LIST_BL_LOCKMASK)); 18: } 19: 20: static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h) 21: { 22: return (struct hlist_bl_node *) 23: ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK); 24: } 25: 26: /** 27: * hlist_bl_del_init_rcu - deletes entry from hash list with re-initialization 28: * @n: the element to delete from the hash list. 29: * 30: * Note: hlist_bl_unhashed() on the node returns true after this. It is 31: * useful for RCU based read lockfree traversal if the writer side 32: * must know if the list entry is still hashed or already unhashed. 33: * 34: * In particular, it means that we can not poison the forward pointers 35: * that may still be used for walking the hash list and we can only 36: * zero the pprev pointer so list_unhashed() will return true after 37: * this. 38: * 39: * The caller must take whatever precautions are necessary (such as 40: * holding appropriate locks) to avoid racing with another 41: * list-mutation primitive, such as hlist_bl_add_head_rcu() or 42: * hlist_bl_del_rcu(), running on this same list. However, it is 43: * perfectly legal to run concurrently with the _rcu list-traversal 44: * primitives, such as hlist_bl_for_each_entry_rcu(). 45: */ 46: static inline void hlist_bl_del_init_rcu(struct hlist_bl_node *n) 47: { 48: if (!hlist_bl_unhashed(n)) { 49: __hlist_bl_del(n); 50: n->pprev = NULL; 51: } 52: } 53: 54: /** 55: * hlist_bl_del_rcu - deletes entry from hash list without re-initialization 56: * @n: the element to delete from the hash list. 57: * 58: * Note: hlist_bl_unhashed() on entry does not return true after this, 59: * the entry is in an undefined state. It is useful for RCU based 60: * lockfree traversal. 61: * 62: * In particular, it means that we can not poison the forward 63: * pointers that may still be used for walking the hash list. 64: * 65: * The caller must take whatever precautions are necessary 66: * (such as holding appropriate locks) to avoid racing 67: * with another list-mutation primitive, such as hlist_bl_add_head_rcu() 68: * or hlist_bl_del_rcu(), running on this same list. 69: * However, it is perfectly legal to run concurrently with 70: * the _rcu list-traversal primitives, such as 71: * hlist_bl_for_each_entry(). 72: */ 73: static inline void hlist_bl_del_rcu(struct hlist_bl_node *n) 74: { 75: __hlist_bl_del(n); 76: n->pprev = LIST_POISON2; 77: } 78: 79: /** 80: * hlist_bl_add_head_rcu 81: * @n: the element to add to the hash list. 82: * @h: the list to add to. 83: * 84: * Description: 85: * Adds the specified element to the specified hlist_bl, 86: * while permitting racing traversals. 87: * 88: * The caller must take whatever precautions are necessary 89: * (such as holding appropriate locks) to avoid racing 90: * with another list-mutation primitive, such as hlist_bl_add_head_rcu() 91: * or hlist_bl_del_rcu(), running on this same list. 92: * However, it is perfectly legal to run concurrently with 93: * the _rcu list-traversal primitives, such as 94: * hlist_bl_for_each_entry_rcu(), used to prevent memory-consistency 95: * problems on Alpha CPUs. Regardless of the type of CPU, the 96: * list-traversal primitive must be guarded by rcu_read_lock(). 97: */ 98: static inline void hlist_bl_add_head_rcu(struct hlist_bl_node *n, 99: struct hlist_bl_head *h) 100: { 101: struct hlist_bl_node *first; 102: 103: /* don't need hlist_bl_first_rcu because we're under lock */ 104: first = hlist_bl_first(h); 105: 106: n->next = first; 107: if (first) 108: first->pprev = &n->next; 109: n->pprev = &h->first; 110: 111: /* need _rcu because we can have concurrent lock free readers */ 112: hlist_bl_set_first_rcu(h, n); 113: } 114: /** 115: * hlist_bl_for_each_entry_rcu - iterate over rcu list of given type 116: * @tpos: the type * to use as a loop cursor. 117: * @pos: the &struct hlist_bl_node to use as a loop cursor. 118: * @head: the head for your list. 119: * @member: the name of the hlist_bl_node within the struct. 120: * 121: */ 122: #define hlist_bl_for_each_entry_rcu(tpos, pos, head, member) \ 123: for (pos = hlist_bl_first_rcu(head); \ 124: pos && \ 125: ({ tpos = hlist_bl_entry(pos, typeof(*tpos), member); 1; }); \ 126: pos = rcu_dereference_raw(pos->next)) 127: 128: #endif 129: