linux-kernel - [PATCH 1/2] workqueue: Use pwq->work_color for wq

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Message-Id: <20251125103126.684929-2-jiangshanlai@gmail.com>
Date: Tue, 25 Nov 2025 18:31:24 +0800
From: Lai Jiangshan <jiangshanlai@...il.com>
To: linux-kernel@...r.kernel.org
Cc: Tejun Heo <tj@...nel.org>,
	Lai Jiangshan <jiangshan.ljs@...group.com>,
	Lai Jiangshan <jiangshanlai@...il.com>
Subject: [PATCH 1/2] workqueue: Use pwq->work_color for wq_barrier

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

wq_barrier work items are internal and do not count as user work items.
They do not participate in flush_workqueue() except for a sanity check,
since wq_barrier owns the PWQ reference. Therefore, any work color is
acceptable; just use the latest pwq->work_color.

See the commit d812796eb390 ("workqueue: Assign a color to barrier work
items").

Signed-off-by: Lai Jiangshan <jiangshan.ljs@...group.com>
---
 kernel/workqueue.c          | 9 ++-------
 kernel/workqueue_internal.h | 1 -
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 253311af47c6..4d817c7144cf 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3187,7 +3187,6 @@ __acquires(&pool->lock)
 	if (worker->task)
 		worker->current_at = worker->task->se.sum_exec_runtime;
 	work_data = *work_data_bits(work);
-	worker->current_color = get_work_color(work_data);
 
 	/*
 	 * Record wq name for cmdline and debug reporting, may get
@@ -3308,7 +3307,6 @@ __acquires(&pool->lock)
 	worker->current_work = NULL;
 	worker->current_func = NULL;
 	worker->current_pwq = NULL;
-	worker->current_color = INT_MAX;
 
 	/* must be the last step, see the function comment */
 	pwq_dec_nr_in_flight(pwq, work_data);
@@ -3796,7 +3794,6 @@ static void insert_wq_barrier(struct pool_workqueue *pwq,
 {
 	static __maybe_unused struct lock_class_key bh_key, thr_key;
 	unsigned int work_flags = 0;
-	unsigned int work_color;
 	struct list_head *head;
 
 	/*
@@ -3826,19 +3823,17 @@ static void insert_wq_barrier(struct pool_workqueue *pwq,
 	 */
 	if (worker) {
 		head = worker->scheduled.next;
-		work_color = worker->current_color;
 	} else {
 		unsigned long *bits = work_data_bits(target);
 
 		head = target->entry.next;
 		/* there can already be other linked works, inherit and set */
 		work_flags |= *bits & WORK_STRUCT_LINKED;
-		work_color = get_work_color(*bits);
 		__set_bit(WORK_STRUCT_LINKED_BIT, bits);
 	}
 
-	pwq->nr_in_flight[work_color]++;
-	work_flags |= work_color_to_flags(work_color);
+	pwq->nr_in_flight[pwq->work_color]++;
+	work_flags |= work_color_to_flags(pwq->work_color);
 
 	insert_work(pwq, &barr->work, head, work_flags);
 }
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index f6275944ada7..76d2d99b26ab 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -32,7 +32,6 @@ struct worker {
 	work_func_t		current_func;	/* K: function */
 	struct pool_workqueue	*current_pwq;	/* K: pwq */
 	u64			current_at;	/* K: runtime at start or last wakeup */
-	unsigned int		current_color;	/* K: color */
 
 	int			sleeping;	/* S: is worker sleeping? */
 
-- 
2.19.1.6.gb485710b