rcu: Move preemption disabling out of __srcu_read_lock()
Currently, __srcu_read_lock() cannot be invoked from restricted
environments because it contains calls to preempt_disable() and
preempt_enable(), both of which can invoke lockdep, which is a bad
idea in some restricted execution modes. This commit therefore moves
the preempt_disable() and preempt_enable() from __srcu_read_lock()
to srcu_read_lock(). It also inserts the preempt_disable() and
preempt_enable() around the call to __srcu_read_lock() in do_exit().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index bdeb456..f5f80c5 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -215,8 +215,11 @@
*/
static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
{
- int retval = __srcu_read_lock(sp);
+ int retval;
+ preempt_disable();
+ retval = __srcu_read_lock(sp);
+ preempt_enable();
rcu_lock_acquire(&(sp)->dep_map);
return retval;
}