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Commit 3120438a authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
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rcu: Disable lockdep checking in RCU list-traversal primitives 



The theory is that use of bare rcu_dereference() is more prone
to error than use of the RCU list-traversal primitives.
Therefore, disable lockdep RCU read-side critical-section
checking in these primitives for the time being.  Once all of
the rcu_dereference() uses have been dealt with, it may be time
to re-enable lockdep checking for the RCU list-traversal
primitives.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-4-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 0632eb3d

include/linux/rculist.h

+7 −7
Original line number Diff line number Diff line
@@ -208,7 +208,7 @@ static inline void list_splice_init_rcu(struct list_head *list, 
 * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().

 */

#define list_entry_rcu(ptr, type, member) \

	container_of(rcu_dereference(ptr), type, member)

	container_of(rcu_dereference_raw(ptr), type, member)



/**

 * list_first_entry_rcu - get the first element from a list
@@ -225,9 +225,9 @@ static inline void list_splice_init_rcu(struct list_head *list, 
	list_entry_rcu((ptr)->next, type, member)



#define __list_for_each_rcu(pos, head) \

	for (pos = rcu_dereference((head)->next); \

	for (pos = rcu_dereference_raw((head)->next); \

		pos != (head); \

		pos = rcu_dereference(pos->next))

		pos = rcu_dereference_raw(pos->next))



/**

 * list_for_each_entry_rcu	-	iterate over rcu list of given type
@@ -257,9 +257,9 @@ static inline void list_splice_init_rcu(struct list_head *list, 
 * as long as the traversal is guarded by rcu_read_lock().

 */

#define list_for_each_continue_rcu(pos, head) \

	for ((pos) = rcu_dereference((pos)->next); \

	for ((pos) = rcu_dereference_raw((pos)->next); \

		prefetch((pos)->next), (pos) != (head); \

		(pos) = rcu_dereference((pos)->next))

		(pos) = rcu_dereference_raw((pos)->next))



/**

 * list_for_each_entry_continue_rcu - continue iteration over list of given type
@@ -418,10 +418,10 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, 
 * as long as the traversal is guarded by rcu_read_lock().

 */

#define hlist_for_each_entry_rcu(tpos, pos, head, member)		 \

	for (pos = rcu_dereference((head)->first);			 \

	for (pos = rcu_dereference_raw((head)->first);			 \

		pos && ({ prefetch(pos->next); 1; }) &&			 \

		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \

		pos = rcu_dereference(pos->next))

		pos = rcu_dereference_raw(pos->next))



#endif	/* __KERNEL__ */

#endif

include/linux/rculist_nulls.h

+2 −2
Original line number Diff line number Diff line
@@ -101,10 +101,10 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n, 
 *

 */

#define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member) \

	for (pos = rcu_dereference((head)->first);			 \

	for (pos = rcu_dereference_raw((head)->first);			 \

		(!is_a_nulls(pos)) &&			\

		({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1; }); \

		pos = rcu_dereference(pos->next))

		pos = rcu_dereference_raw(pos->next))



#endif

#endif