linux-kernel - [RFC PATCH 8/8] workqueue: Move the locking out of maybe_create

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220804084135.92425-9-jiangshanlai@gmail.com>
Date:   Thu,  4 Aug 2022 16:41:35 +0800
From:   Lai Jiangshan <jiangshanlai@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Lai Jiangshan <jiangshan.ljs@...group.com>,
        Tejun Heo <tj@...nel.org>,
        Lai Jiangshan <jiangshanlai@...il.com>
Subject: [RFC PATCH 8/8] workqueue: Move the locking out of maybe_create_worker()

From: Lai Jiangshan <jiangshan.ljs@...group.com>

The code is cleaner if the reversed pair of unlock() and lock()
is moved into the caller.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@...group.com>
---
 kernel/workqueue.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0d9844b81482..013ad61e67b9 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2091,17 +2091,10 @@ static void pool_mayday_timeout(struct timer_list *t)
  * sent to all rescuers with works scheduled on @pool to resolve
  * possible allocation deadlock.
  *
- * LOCKING:
- * raw_spin_lock_irq(pool->lock) which may be released and regrabbed
- * multiple times.  Does GFP_KERNEL allocations.  Called only from
- * manager.
+ * Does GFP_KERNEL allocations.  Called only from manager.
  */
 static void maybe_create_worker(struct worker_pool *pool)
-__releases(&pool->lock)
-__acquires(&pool->lock)
 {
-	raw_spin_unlock_irq(&pool->lock);
-
 	/* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
 	mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
 
@@ -2116,7 +2109,6 @@ __acquires(&pool->lock)
 	}
 
 	del_timer_sync(&pool->mayday_timer);
-	raw_spin_lock_irq(&pool->lock);
 }
 
 /**
@@ -2147,7 +2139,9 @@ static bool manage_workers(struct worker *worker)
 	pool->flags |= POOL_MANAGER_ACTIVE;
 	pool->manager = worker;
 
+	raw_spin_unlock_irq(&pool->lock);
 	maybe_create_worker(pool);
+	raw_spin_lock_irq(&pool->lock);
 
 	pool->manager = NULL;
 	pool->flags &= ~POOL_MANAGER_ACTIVE;
-- 
2.19.1.6.gb485710b