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rcu: Add support for consolidated-RCU reader checking

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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>
This commit is contained in:
Joel Fernandes (Google)
2019-07-16 18:12:22 -04:00
committed by Paul E. McKenney
parent 9147089bee
commit 28875945ba
4 changed files with 108 additions and 38 deletions
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32
include/linux/rculist.h
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@@ -40,6 +40,24 @@ 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.
*
@@ -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(\