[tip:timers/core] timers: Create detach_if_pending() and use it

From: tip-bot for Thomas Gleixner
Date: Wed Jun 06 2012 - 07:59:07 EST


Commit-ID: ec44bc7acc3687ba6ae8154b4b5a845b70279237
Gitweb: http://git.kernel.org/tip/ec44bc7acc3687ba6ae8154b4b5a845b70279237
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Fri, 25 May 2012 22:08:57 +0000
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Wed, 6 Jun 2012 13:49:01 +0200

timers: Create detach_if_pending() and use it

Most callers of detach_timer() have the same pattern around
them. Check whether the timer is pending and eventually updating
base->next_timer.

Create detach_if_pending() and replace the duplicated code.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20120525214819.131246037@xxxxxxxxxxxxx

---
kernel/timer.c | 56 +++++++++++++++++++++++---------------------------------
1 files changed, 23 insertions(+), 33 deletions(-)

diff --git a/kernel/timer.c b/kernel/timer.c
index 6ec7e7e..0f70deb 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -654,8 +654,7 @@ void init_timer_deferrable_key(struct timer_list *timer,
}
EXPORT_SYMBOL(init_timer_deferrable_key);

-static inline void detach_timer(struct timer_list *timer,
- int clear_pending)
+static inline void detach_timer(struct timer_list *timer, bool clear_pending)
{
struct list_head *entry = &timer->entry;

@@ -667,6 +666,19 @@ static inline void detach_timer(struct timer_list *timer,
entry->prev = LIST_POISON2;
}

+static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
+ bool clear_pending)
+{
+ if (!timer_pending(timer))
+ return 0;
+
+ detach_timer(timer, clear_pending);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
+ return 1;
+}
+
/*
* We are using hashed locking: holding per_cpu(tvec_bases).lock
* means that all timers which are tied to this base via timer->base are
@@ -712,16 +724,9 @@ __mod_timer(struct timer_list *timer, unsigned long expires,

base = lock_timer_base(timer, &flags);

- if (timer_pending(timer)) {
- detach_timer(timer, 0);
- if (timer->expires == base->next_timer &&
- !tbase_get_deferrable(timer->base))
- base->next_timer = base->timer_jiffies;
- ret = 1;
- } else {
- if (pending_only)
- goto out_unlock;
- }
+ ret = detach_if_pending(timer, base, false);
+ if (!ret && pending_only)
+ goto out_unlock;

debug_activate(timer, expires);

@@ -959,13 +964,7 @@ int del_timer(struct timer_list *timer)
timer_stats_timer_clear_start_info(timer);
if (timer_pending(timer)) {
base = lock_timer_base(timer, &flags);
- if (timer_pending(timer)) {
- detach_timer(timer, 1);
- if (timer->expires == base->next_timer &&
- !tbase_get_deferrable(timer->base))
- base->next_timer = base->timer_jiffies;
- ret = 1;
- }
+ ret = detach_if_pending(timer, base, true);
spin_unlock_irqrestore(&base->lock, flags);
}

@@ -990,19 +989,10 @@ int try_to_del_timer_sync(struct timer_list *timer)

base = lock_timer_base(timer, &flags);

- if (base->running_timer == timer)
- goto out;
-
- timer_stats_timer_clear_start_info(timer);
- ret = 0;
- if (timer_pending(timer)) {
- detach_timer(timer, 1);
- if (timer->expires == base->next_timer &&
- !tbase_get_deferrable(timer->base))
- base->next_timer = base->timer_jiffies;
- ret = 1;
+ if (base->running_timer != timer) {
+ timer_stats_timer_clear_start_info(timer);
+ ret = detach_if_pending(timer, base, true);
}
-out:
spin_unlock_irqrestore(&base->lock, flags);

return ret;
@@ -1178,7 +1168,7 @@ static inline void __run_timers(struct tvec_base *base)
timer_stats_account_timer(timer);

base->running_timer = timer;
- detach_timer(timer, 1);
+ detach_timer(timer, true);

spin_unlock_irq(&base->lock);
call_timer_fn(timer, fn, data);
@@ -1714,7 +1704,7 @@ static void migrate_timer_list(struct tvec_base *new_base, struct list_head *hea

while (!list_empty(head)) {
timer = list_first_entry(head, struct timer_list, entry);
- detach_timer(timer, 0);
+ detach_timer(timer, false);
timer_set_base(timer, new_base);
if (time_before(timer->expires, new_base->next_timer) &&
!tbase_get_deferrable(timer->base))
--
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