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authorJoel Fernandes (Google) <joel@joelfernandes.org>2019-07-16 18:12:22 -0400
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-08-09 11:00:35 -0700
commit28875945ba98d1b47a8a706812b6494d165bb0a0 (patch)
treea167811c3e2dfe5de312c187085ed53f21faf831 /include/linux/rculist.h
parent9147089bee3a6b504821dd8462e2be229e6dbfae (diff)
rcu: Add support for consolidated-RCU reader checking
This commit adds RCU-reader checks to list_for_each_entry_rcu() and hlist_for_each_entry_rcu(). These checks are optional, and are indicated by a lockdep expression passed to a new optional argument to these two macros. If this optional lockdep expression is omitted, these two macros act as before, checking for an RCU read-side critical section. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> [ paulmck: Update to eliminate return within macro and update comment. ] Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'include/linux/rculist.h')
-rw-r--r--include/linux/rculist.h32
1 files changed, 27 insertions, 5 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index 932296144131..4158b7212936 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -41,6 +41,24 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list)
#define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next)))
/*
+ * Check during list traversal that we are within an RCU reader
+ */
+
+#define check_arg_count_one(dummy)
+
+#ifdef CONFIG_PROVE_RCU_LIST
+#define __list_check_rcu(dummy, cond, extra...) \
+ ({ \
+ check_arg_count_one(extra); \
+ RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \
+ "RCU-list traversed in non-reader section!"); \
+ })
+#else
+#define __list_check_rcu(dummy, cond, extra...) \
+ ({ check_arg_count_one(extra); })
+#endif
+
+/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
@@ -343,14 +361,16 @@ static inline void list_splice_tail_init_rcu(struct list_head *list,
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_head within the struct.
+ * @cond: optional lockdep expression if called from non-RCU protection.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as list_add_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
-#define list_for_each_entry_rcu(pos, head, member) \
- for (pos = list_entry_rcu((head)->next, typeof(*pos), member); \
- &pos->member != (head); \
+#define list_for_each_entry_rcu(pos, head, member, cond...) \
+ for (__list_check_rcu(dummy, ## cond, 0), \
+ pos = list_entry_rcu((head)->next, typeof(*pos), member); \
+ &pos->member != (head); \
pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
/**
@@ -616,13 +636,15 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n,
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
+ * @cond: optional lockdep expression if called from non-RCU protection.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
-#define hlist_for_each_entry_rcu(pos, head, member) \
- for (pos = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),\
+#define hlist_for_each_entry_rcu(pos, head, member, cond...) \
+ for (__list_check_rcu(dummy, ## cond, 0), \
+ pos = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),\
typeof(*(pos)), member); \
pos; \
pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\