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Message-Id: <1348481238-6138-8-git-send-email-laijs@cn.fujitsu.com>
Date: Mon, 24 Sep 2012 18:07:09 +0800
From: Lai Jiangshan <laijs@...fujitsu.com>
To: Tejun Heo <tj@...nel.org>, linux-kernel@...r.kernel.org
Cc: Lai Jiangshan <laijs@...fujitsu.com>
Subject: [PATCH 07/10] workqueue: simplify flush_workqueue_prep_cwqs()
Move the advance of wq->work_color into flush_workqueue_prep_cwqs()
and rename flush_workqueue_prep_cwqs() to workqueue_start_flush(),
It will simplify the caller.
Since the @flush_color and @work_color can't be -1, so we remove
the test in workqueue_start_flush() and fix the indent.
Since the @flush_color is always equals to wq->work_color(before advance),
so we remove the @flush_color argument. @flush_color becomes a
local variable.
Since the @work_color is always equals to work_next_color(flush_color),
so we remove the @work_color argument. @work_color is renamed to
@next_color and becomes a local variable
This patch doesn't make any functional difference.
Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com>
---
kernel/workqueue.c | 69 +++++++++++++++++++--------------------------------
1 files changed, 26 insertions(+), 43 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 803a22c..be407e1 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2531,40 +2531,37 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
}
/**
- * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing
+ * workqueue_start_flush - start workqueue flushing
* @wq: workqueue being flushed
- * @flush_color: new flush color, < 0 for no-op
- * @work_color: new work color, < 0 for no-op
*
- * Prepare cwqs for workqueue flushing.
+ * Start a new flush color and prepare cwqs for workqueue flushing.
*
- * The caller should have initialized @wq->first_flusher prior to
- * calling this function with non-negative @flush_color. If
- * @flush_color is negative, no flush color update is done and %false
- * is returned.
+ * Called with color space is not full. The current work_color
+ * becomes new flush_color and work_color is advanced by one.
+ * All cwq's work_color are set to new work_color(advanced by one).
*
- * If @work_color is non-negative, all cwqs should have the same
- * work_color which is previous to @work_color and all will be
- * advanced to @work_color.
+ * The caller should have initialized @wq->first_flusher prior to
+ * calling this function.
*
* CONTEXT:
* mutex_lock(wq->flush_mutex).
*
* RETURNS:
- * %true if @flush_color >= 0 and there's something to flush. %false
- * otherwise.
+ * %true if there's some cwqs to flush. %false otherwise.
*/
-static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq,
- int flush_color, int work_color)
+static bool workqueue_start_flush(struct workqueue_struct *wq)
{
+ int flush_color = wq->work_color;
+ int next_color = work_next_color(wq->work_color);
bool wait = false;
unsigned int cpu;
- if (flush_color >= 0) {
- BUG_ON(atomic_read(&wq->nr_cwqs_to_flush[flush_color]));
- /* this ref is held by first flusher */
- atomic_set(&wq->nr_cwqs_to_flush[flush_color], 1);
- }
+ BUG_ON(next_color == wq->flush_color);
+ wq->work_color = next_color;
+
+ BUG_ON(atomic_read(&wq->nr_cwqs_to_flush[flush_color]));
+ /* this ref is held by first flusher */
+ atomic_set(&wq->nr_cwqs_to_flush[flush_color], 1);
for_each_cwq_cpu(cpu, wq) {
struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
@@ -2572,17 +2569,13 @@ static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq,
spin_lock_irq(&gcwq->lock);
- if (flush_color >= 0) {
- if (cwq->nr_in_flight[flush_color]) {
- atomic_inc(&wq->nr_cwqs_to_flush[flush_color]);
- wait = true;
- }
+ if (cwq->nr_in_flight[flush_color]) {
+ atomic_inc(&wq->nr_cwqs_to_flush[flush_color]);
+ wait = true;
}
- if (work_color >= 0) {
- BUG_ON(work_color != work_next_color(cwq->work_color));
- cwq->work_color = work_color;
- }
+ BUG_ON(next_color != work_next_color(cwq->work_color));
+ cwq->work_color = next_color;
spin_unlock_irq(&gcwq->lock);
}
@@ -2622,14 +2615,9 @@ void flush_workqueue(struct workqueue_struct *wq)
next_color = work_next_color(wq->work_color);
if (next_color != wq->flush_color) {
- /*
- * Color space is not full. The current work_color
- * becomes our flush_color and work_color is advanced
- * by one.
- */
+ /* Color space is not full */
BUG_ON(!list_empty(&wq->flusher_overflow));
this_flusher.flush_color = flush_color;
- wq->work_color = next_color;
if (!wq->first_flusher) {
/* no flush in progress, become the first flusher */
@@ -2637,8 +2625,7 @@ void flush_workqueue(struct workqueue_struct *wq)
wq->first_flusher = &this_flusher;
- if (!flush_workqueue_prep_cwqs(wq, flush_color,
- wq->work_color)) {
+ if (!workqueue_start_flush(wq)) {
/* nothing to flush, done */
wq_dec_flusher_ref(wq, flush_color);
wq->flush_color = next_color;
@@ -2651,8 +2638,7 @@ void flush_workqueue(struct workqueue_struct *wq)
/* wait in queue */
BUG_ON(wq->flush_color == this_flusher.flush_color);
list_add_tail(&this_flusher.list, &wq->flusher_queue);
- flush_workqueue_prep_cwqs(wq, flush_color,
- wq->work_color);
+ workqueue_start_flush(wq);
}
} else {
/*
@@ -2707,12 +2693,9 @@ void flush_workqueue(struct workqueue_struct *wq)
list_for_each_entry(tmp, &wq->flusher_overflow, list)
tmp->flush_color = wq->work_color;
- flush_color = wq->work_color;
- wq->work_color = work_next_color(wq->work_color);
-
list_splice_tail_init(&wq->flusher_overflow,
&wq->flusher_queue);
- flush_workqueue_prep_cwqs(wq, flush_color, wq->work_color);
+ workqueue_start_flush(wq);
}
if (list_empty(&wq->flusher_queue)) {
--
1.7.4.4
--
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