linux-kernel - [PATCH 1/3] workqueue: remove the first check and the return value of maybe_create

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Date:	Fri, 11 Jul 2014 00:01:03 +0800
From:	Lai Jiangshan <laijs@...fujitsu.com>
To:	<linux-kernel@...r.kernel.org>
CC:	Tejun Heo <tj@...nel.org>, Lai Jiangshan <laijs@...fujitsu.com>
Subject: [PATCH 1/3] workqueue: remove the first check and the return value of maybe_create_worker()

The pool->lock is kept locked during the time the worker_thread() checks the
condition and maybe_create_worker() is called, therefore, the condition
is unchanged and the first condition check is unneeded.

After this unneeded check is removed, maybe_create_worker() only returns
true, so we remove the return value of it and adjust the call-site.

Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com>
---
 kernel/workqueue.c |   18 +++++-------------
 1 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f344334..92f7ea0c 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1887,17 +1887,11 @@ static void pool_mayday_timeout(unsigned long __pool)
  * spin_lock_irq(pool->lock) which may be released and regrabbed
  * multiple times.  Does GFP_KERNEL allocations.  Called only from
  * manager.
- *
- * Return:
- * %false if no action was taken and pool->lock stayed locked, %true
- * otherwise.
  */
-static bool maybe_create_worker(struct worker_pool *pool)
+static void maybe_create_worker(struct worker_pool *pool)
 __releases(&pool->lock)
 __acquires(&pool->lock)
 {
-	if (!need_to_create_worker(pool))
-		return false;
 restart:
 	spin_unlock_irq(&pool->lock);
 
@@ -1914,7 +1908,7 @@ restart:
 			start_worker(worker);
 			if (WARN_ON_ONCE(need_to_create_worker(pool)))
 				goto restart;
-			return true;
+			return;
 		}
 
 		if (!need_to_create_worker(pool))
@@ -1930,7 +1924,6 @@ restart:
 	spin_lock_irq(&pool->lock);
 	if (need_to_create_worker(pool))
 		goto restart;
-	return true;
 }
 
 /**
@@ -1959,7 +1952,6 @@ restart:
 static bool manage_workers(struct worker *worker)
 {
 	struct worker_pool *pool = worker->pool;
-	bool ret = false;
 
 	/*
 	 * Anyone who successfully grabs manager_arb wins the arbitration
@@ -1972,12 +1964,12 @@ static bool manage_workers(struct worker *worker)
 	 * actual management, the pool may stall indefinitely.
 	 */
 	if (!mutex_trylock(&pool->manager_arb))
-		return ret;
+		return false;
 
-	ret |= maybe_create_worker(pool);
+	maybe_create_worker(pool);
 
 	mutex_unlock(&pool->manager_arb);
-	return ret;
+	return true;
 }
 
 /**
-- 
1.7.4.4

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