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authorLai Jiangshan <laijs@cn.fujitsu.com>2012-11-29 12:46:05 +0400
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-02-08 03:10:39 +0400
commit3bc97a782cc8c112f64a25143452b06206364cc8 (patch)
treeb09b1d1be6158948d9bb0f848dcd3d66f3b17737 /include/linux/srcu.h
parentab4d2986e44c589aa1b647d7da5e21c2707babea (diff)
downloadlinux-3bc97a782cc8c112f64a25143452b06206364cc8.tar.xz
srcu: Remove checks preventing offline CPUs from calling srcu_read_lock()
SRCU has its own statemachine and no longer relies on normal RCU. Its read-side critical section can now be used by an offline CPU, so this commit removes the check and the comments, reverting the SRCU portion of c0d6d01b (rcu: Check for illegal use of RCU from offlined CPUs). It also makes the code match the comments in whatisRCU.txt: g. Do you need read-side critical sections that are respected even though they are in the middle of the idle loop, during user-mode execution, or on an offlined CPU? If so, SRCU is the only choice that will work for you. [ paulmck: There is at least one remaining issue, namely use of lockdep with tracing enabled. ] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/srcu.h')
-rw-r--r--include/linux/srcu.h5
1 files changed, 0 insertions, 5 deletions
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 6eb691b08358..ae3ee39eb699 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -163,9 +163,6 @@ void srcu_barrier(struct srcu_struct *sp);
* power mode. This way we can notice an extended quiescent state to
* other CPUs that started a grace period. Otherwise we would delay any
* grace period as long as we run in the idle task.
- *
- * Similarly, we avoid claiming an SRCU read lock held if the current
- * CPU is offline.
*/
static inline int srcu_read_lock_held(struct srcu_struct *sp)
{
@@ -173,8 +170,6 @@ static inline int srcu_read_lock_held(struct srcu_struct *sp)
return 1;
if (rcu_is_cpu_idle())
return 0;
- if (!rcu_lockdep_current_cpu_online())
- return 0;
return lock_is_held(&sp->dep_map);
}