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authorThomas Gleixner <tglx@linutronix.de>2013-07-04 23:11:22 +0200
committerThomas Gleixner <tglx@linutronix.de>2013-07-04 23:11:22 +0200
commit2b0f89317e99735bbf32eaede81f707f98ab1b5e (patch)
tree16daa236e21876b11f1c0b9256cd4046aadba020 /include/linux/rculist_nulls.h
parent07bd1172902e782f288e4d44b1fde7dec0f08b6f (diff)
parentfa18f7bde3ad4568d1d343b60d963bfbd8dc3991 (diff)
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Merge branch 'timers/posix-cpu-timers-for-tglx' of
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/core Frederic sayed: "Most of these patches have been hanging around for several month now, in -mmotm for a significant chunk. They already missed a few releases." Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/rculist_nulls.h')
-rw-r--r--include/linux/rculist_nulls.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h
index 2ae13714828b..1c33dd7da4a7 100644
--- a/include/linux/rculist_nulls.h
+++ b/include/linux/rculist_nulls.h
@@ -105,9 +105,14 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
* @head: the head for your list.
* @member: the name of the hlist_nulls_node within the struct.
*
+ * The barrier() is needed to make sure compiler doesn't cache first element [1],
+ * as this loop can be restarted [2]
+ * [1] Documentation/atomic_ops.txt around line 114
+ * [2] Documentation/RCU/rculist_nulls.txt around line 146
*/
#define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member) \
- for (pos = rcu_dereference_raw(hlist_nulls_first_rcu(head)); \
+ for (({barrier();}), \
+ pos = rcu_dereference_raw(hlist_nulls_first_rcu(head)); \
(!is_a_nulls(pos)) && \
({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1; }); \
pos = rcu_dereference_raw(hlist_nulls_next_rcu(pos)))