workqueue: Convert for_each_wq to use built-in list check

Because list_for_each_entry_rcu() can now check for holding a
lock as well as for being in an RCU read-side critical section,
this commit replaces the workqueue_sysfs_unregister() function's
use of assert_rcu_or_wq_mutex() and list_for_each_entry_rcu() with
list_for_each_entry_rcu() augmented with a lockdep_is_held() optional
argument.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index bc2e09a8ea61db57cec3ca455850df4fd1139849..e501c79e283adc5cd5df4ab7d87696a0e74acdde 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -364,11 +364,6 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
                         !lockdep_is_held(&wq_pool_mutex),              \
                         "RCU or wq_pool_mutex should be held")
 
-#define assert_rcu_or_wq_mutex(wq)                                     \
-       RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&                       \
-                        !lockdep_is_held(&wq->mutex),                  \
-                        "RCU or wq->mutex should be held")
-
 #define assert_rcu_or_wq_mutex_or_pool_mutex(wq)                       \
        RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&                       \
                         !lockdep_is_held(&wq->mutex) &&                \
@@ -425,9 +420,8 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
  * ignored.
  */
 #define for_each_pwq(pwq, wq)                                          \
-       list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node)          \
-               if (({ assert_rcu_or_wq_mutex(wq); false; })) { }       \
-               else
+       list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node,          \
+                                lockdep_is_held(&(wq->mutex)))
 
 #ifdef CONFIG_DEBUG_OBJECTS_WORK