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| author | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-05-13 15:57:50 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-08-13 14:35:49 -0700 |
| commit | e6060b41c9955374079926a7612b857a8458ed1f (patch) | |
| tree | 297581f29d4caec633aa474b3b4dc30f16e5cffe /kernel/rcu/rcu_segcblist.h | |
| parent | 76c6927c3ee443e756f2c0c9f992cb04b26c65f2 (diff) | |
| download | lwn-e6060b41c9955374079926a7612b857a8458ed1f.tar.gz lwn-e6060b41c9955374079926a7612b857a8458ed1f.zip | |
rcu/nocb: Allow lockless use of rcu_segcblist_empty()
Currently, rcu_segcblist_empty() assumes that the callback list is not
being changed by other CPUs, but upcoming changes will require it to
operate locklessly. This commit therefore adds the needed READ_ONCE()
call, along with the WRITE_ONCE() calls when updating the callback list's
->head field.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel/rcu/rcu_segcblist.h')
| -rw-r--r-- | kernel/rcu/rcu_segcblist.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index f74960f0305c..d9142b3590a8 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -36,7 +36,7 @@ struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp); */ static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp) { - return !rsclp->head; + return !READ_ONCE(rsclp->head); } /* Return number of callbacks in segmented callback list. */ |