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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue, 11 Jun 2019 11:21:09 +0200
Subject: [PATCH 3/4] workqueue: Use swait for wq_manager_wait
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.3-rt1.tar.xz
In order for the workqueue code use raw_spinlock_t typed locking there
must not be a spinlock_t typed lock be acquired. A wait_queue_head uses
a spinlock_t lock for its list protection.
Use a swait based queue head to avoid raw_spinlock_t -> spinlock_t
locking.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/workqueue.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -50,6 +50,7 @@
#include <linux/uaccess.h>
#include <linux/sched/isolation.h>
#include <linux/nmi.h>
+#include <linux/swait.h>
#include "workqueue_internal.h"
@@ -301,7 +302,7 @@ static struct workqueue_attrs *wq_update
static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */
static DEFINE_MUTEX(wq_pool_attach_mutex); /* protects worker attach/detach */
static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */
-static DECLARE_WAIT_QUEUE_HEAD(wq_manager_wait); /* wait for manager to go away */
+static DECLARE_SWAIT_QUEUE_HEAD(wq_manager_wait); /* wait for manager to go away */
static LIST_HEAD(workqueues); /* PR: list of all workqueues */
static bool workqueue_freezing; /* PL: have wqs started freezing? */
@@ -2137,7 +2138,7 @@ static bool manage_workers(struct worker
pool->manager = NULL;
pool->flags &= ~POOL_MANAGER_ACTIVE;
- wake_up(&wq_manager_wait);
+ swake_up_one(&wq_manager_wait);
return true;
}
@@ -3532,7 +3533,7 @@ static void put_unbound_pool(struct work
* manager and @pool gets freed with the flag set.
*/
spin_lock_irq(&pool->lock);
- wait_event_lock_irq(wq_manager_wait,
+ swait_event_lock_irq(wq_manager_wait,
!(pool->flags & POOL_MANAGER_ACTIVE), pool->lock);
pool->flags |= POOL_MANAGER_ACTIVE;
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