wrapper/list.h

   1 /* SPDX-License-Identifier: GPL-2.0-only
   2  *
   3  * wrapper/list.h
   4  *
   5  * wrapper around linux/list.h.
   6  *
   7  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * This wrapper code is derived from Linux 3.19.2 include/linux/list.h
  10  * and include/linux/rculist.h, hence the GPLv2 license applied to this
  11  * file.
  12  */
  13
  14 #ifndef _LTTNG_WRAPPER_LIST_H
  15 #define _LTTNG_WRAPPER_LIST_H
  16
  17 #include <linux/list.h>
  18 #include <linux/rculist.h>
  19
  20 /*
  21  * return the first or the next element in an RCU protected hlist
  22  */
  23 #define lttng_hlist_first_rcu(head)     (*((struct hlist_node __rcu **)(&(head)->first)))
  24 #define lttng_hlist_next_rcu(node)      (*((struct hlist_node __rcu **)(&(node)->next)))
  25 #define lttng_hlist_pprev_rcu(node)     (*((struct hlist_node __rcu **)((node)->pprev)))
  26
  27 #define lttng_hlist_entry_safe(ptr, type, member) \
  28         ({ typeof(ptr) ____ptr = (ptr); \
  29            ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
  30         })
  31
  32 /**
  33  * lttng_hlist_for_each_entry   - iterate over list of given type
  34  * @pos:        the type * to use as a loop cursor.
  35  * @head:       the head for your list.
  36  * @member:     the name of the hlist_node within the struct.
  37  */
  38 #define lttng_hlist_for_each_entry(pos, head, member)                   \
  39         for (pos = lttng_hlist_entry_safe((head)->first, typeof(*(pos)), member);\
  40              pos;                                                       \
  41              pos = lttng_hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
  42
  43 /**
  44  * lttng_hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
  45  * @pos:        the type * to use as a loop cursor.
  46  * @n:          another &struct hlist_node to use as temporary storage
  47  * @head:       the head for your list.
  48  * @member:     the name of the hlist_node within the struct.
  49  */
  50 #define lttng_hlist_for_each_entry_safe(pos, n, head, member)           \
  51         for (pos = lttng_hlist_entry_safe((head)->first, typeof(*pos), member);\
  52              pos && ({ n = pos->member.next; 1; });                     \
  53              pos = lttng_hlist_entry_safe(n, typeof(*pos), member))
  54
  55 #endif /* _LTTNG_WRAPPER_LIST_H */