timers: Remove set_timer_slack() leftovers

We now have implicit batching in the timer wheel. The slack API is no longer
used, so remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrew F. Davis <afd@ti.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Chris Mason <clm@fb.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Nyman <mathias.nyman@intel.com>
Cc: Pali Rohár <pali.rohar@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mmc@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160704094342.189813118@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

8 files changed, 1 insertions, 38 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 9f42526b4d62..f06d7f3b075b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1523,12 +1523,7 @@ static void __disk_unblock_events(struct gendisk *disk, bool check_now)
         if (--ev->block)
                 goto out_unlock;
 
-        /*
-         * Not exactly a latency critical operation, set poll timer
-         * slack to 25% and kick event check.
-         */
         intv = disk_events_poll_jiffies(disk);
-        set_timer_slack(&ev->dwork.timer, intv / 4);
         if (check_now)
                 queue_delayed_work(system_freezable_power_efficient_wq,
                                 &ev->dwork, 0);
diff --git a/drivers/mmc/host/jz4740_mmc.c b/drivers/mmc/host/jz4740_mmc.c
index 03ddf0ecf402..684087db170b 100644
--- a/drivers/mmc/host/jz4740_mmc.c
+++ b/drivers/mmc/host/jz4740_mmc.c
@@ -1068,8 +1068,6 @@ static int jz4740_mmc_probe(struct platform_device* pdev)
         jz4740_mmc_clock_disable(host);
         setup_timer(&host->timeout_timer, jz4740_mmc_timeout,
                         (unsigned long)host);
-        /* It is not important when it times out, it just needs to timeout. */
-        set_timer_slack(&host->timeout_timer, HZ);
 
         host->use_dma = true;
         if (host->use_dma && jz4740_mmc_acquire_dma_channels(host) != 0)
diff --git a/drivers/power/bq27xxx_battery.c b/drivers/power/bq27xxx_battery.c
index 45f6ebf88df6..e90b3f307e0f 100644
--- a/drivers/power/bq27xxx_battery.c
+++ b/drivers/power/bq27xxx_battery.c
@@ -735,11 +735,8 @@ static void bq27xxx_battery_poll(struct work_struct *work)
 
         bq27xxx_battery_update(di);
 
-        if (poll_interval > 0) {
-                /* The timer does not have to be accurate. */
-                set_timer_slack(&di->work.timer, poll_interval * HZ / 4);
+        if (poll_interval > 0)
                 schedule_delayed_work(&di->work, poll_interval * HZ);
-        }
 }
 
 /*
diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 0449235d4f22..1700908b84ef 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -500,7 +500,6 @@ static int ohci_init (struct ohci_hcd *ohci)
 
         setup_timer(&ohci->io_watchdog, io_watchdog_func,
                         (unsigned long) ohci);
-        set_timer_slack(&ohci->io_watchdog, msecs_to_jiffies(20));
 
         ohci->hcca = dma_alloc_coherent (hcd->self.controller,
                         sizeof(*ohci->hcca), &ohci->hcca_dma, GFP_KERNEL);
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index f2f9518c53ab..a986fe763d87 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -490,8 +490,6 @@ static void compliance_mode_recovery_timer_init(struct xhci_hcd *xhci)
         xhci->comp_mode_recovery_timer.expires = jiffies +
                         msecs_to_jiffies(COMP_MODE_RCVRY_MSECS);
 
-        set_timer_slack(&xhci->comp_mode_recovery_timer,
-                        msecs_to_jiffies(COMP_MODE_RCVRY_MSECS));
         add_timer(&xhci->comp_mode_recovery_timer);
         xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                         "Compliance mode recovery timer initialized");
diff --git a/include/linux/timer.h b/include/linux/timer.h
index 5869ab9848fe..4419506b564e 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -19,7 +19,6 @@ struct timer_list {
         void                    (*function)(unsigned long);
         unsigned long           data;
         u32                     flags;
-        int                     slack;
 
 #ifdef CONFIG_TIMER_STATS
         int                     start_pid;
@@ -73,7 +72,6 @@ struct timer_list {
                 .expires = (_expires),                          \
                 .data = (_data),                                \
                 .flags = (_flags),                              \
-                .slack = -1,                                    \
                 __TIMER_LOCKDEP_MAP_INITIALIZER(                \
                         __FILE__ ":" __stringify(__LINE__))     \
         }
@@ -193,8 +191,6 @@ extern int del_timer(struct timer_list * timer);
 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 
-extern void set_timer_slack(struct timer_list *time, int slack_hz);
-
 /*
  * The jiffies value which is added to now, when there is no timer
  * in the timer wheel:
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 86e95b72665d..a83e23d0bc25 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -447,24 +447,6 @@ unsigned long round_jiffies_up_relative(unsigned long j)
 }
 EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
 
-/**
- * set_timer_slack - set the allowed slack for a timer
- * @timer: the timer to be modified
- * @slack_hz: the amount of time (in jiffies) allowed for rounding
- *
- * Set the amount of time, in jiffies, that a certain timer has
- * in terms of slack. By setting this value, the timer subsystem
- * will schedule the actual timer somewhere between
- * the time mod_timer() asks for, and that time plus the slack.
- *
- * By setting the slack to -1, a percentage of the delay is used
- * instead.
- */
-void set_timer_slack(struct timer_list *timer, int slack_hz)
-{
-        timer->slack = slack_hz;
-}
-EXPORT_SYMBOL_GPL(set_timer_slack);
 
 static inline unsigned int timer_get_idx(struct timer_list *timer)
 {
@@ -775,7 +757,6 @@ static void do_init_timer(struct timer_list *timer, unsigned int flags,
 {
         timer->entry.pprev = NULL;
         timer->flags = flags | raw_smp_processor_id();
-        timer->slack = -1;
 #ifdef CONFIG_TIMER_STATS
         timer->start_site = NULL;
         timer->start_pid = -1;
diff --git a/lib/random32.c b/lib/random32.c
index 510d1ce7d4d2..69ed593aab07 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -233,7 +233,6 @@ static void __prandom_timer(unsigned long dontcare)
 
 static void __init __prandom_start_seed_timer(void)
 {
-        set_timer_slack(&seed_timer, HZ);
         seed_timer.expires = jiffies + msecs_to_jiffies(40 * MSEC_PER_SEC);
         add_timer(&seed_timer);
 }