[tip: core/urgent] workqueue: Convert for_each_wq to use built-in list check

[tip-bot2 for Joel Fernandes (Google)]

The following commit has been merged into the core/urgent branch of tip:

Commit-ID:     ac91dcca87e4300ea30e9514c31064d32469dd6d
Gitweb:        https://git.kernel.org/tip/ac91dcca87e4300ea30e9514c31064d32469dd6d
Author:        Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
AuthorDate:    Thu, 15 Aug 2019 10:18:42 -04:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Mon, 18 Nov 2019 16:20:00 +01:00

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.

[ Cherry-picked from: 5a6446626d7e: ("workqueue: Convert for_each_wq to use built-in list check") ]

Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/workqueue.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index bc2e09a..e501c79 100644
--- 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