workqueue: use mod_delayed_work() instead of cancel + queue

Convert delayed_work users doing cancel_delayed_work() followed by
queue_delayed_work() to mod_delayed_work().

Most conversions are straight-forward.  Ones worth mentioning are,

* drivers/edac/edac_mc.c: edac_mc_workq_setup() converted to always
  use mod_delayed_work() and cancel loop in
  edac_mc_reset_delay_period() is dropped.

* drivers/platform/x86/thinkpad_acpi.c: No need to remember whether
  watchdog is active or not.  @fan_watchdog_active and related code
  dropped.

* drivers/power/charger-manager.c: Seemingly a lot of
  delayed_work_pending() abuse going on here.
  [delayed_]work_pending() are unsynchronized and racy when used like
  this.  I converted one instance in fullbatt_handler().  Please
  conver the rest so that it invokes workqueue APIs for the intended
  target state rather than trying to game work item pending state
  transitions.  e.g. if timer should be modified - call
  mod_delayed_work(), canceled - call cancel_delayed_work[_sync]().

* drivers/thermal/thermal_sys.c: thermal_zone_device_set_polling()
  simplified.  Note that round_jiffies() calls in this function are
  meaningless.  round_jiffies() work on absolute jiffies not delta
  delay used by delayed_work.

v2: Tomi pointed out that __cancel_delayed_work() users can't be
    safely converted to mod_delayed_work().  They could be calling it
    from irq context and if that happens while delayed_work_timer_fn()
    is running, it could deadlock.  __cancel_delayed_work() users are
    dropped.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Doug Thompson <dougthompson@xmission.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Roland Dreier <roland@kernel.org>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Johannes Berg <johannes@sipsolutions.net>

18 files changed, 41 insertions, 105 deletions

diff --git a/block/genhd.c b/block/genhd.c
index cac7366957c3..5d8b44a6442b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1534,10 +1534,8 @@ void disk_flush_events(struct gendisk *disk, unsigned int mask)
 
         spin_lock_irq(&ev->lock);
         ev->clearing |= mask;
-        if (!ev->block) {
-                cancel_delayed_work(&ev->dwork);
-                queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, 0);
-        }
+        if (!ev->block)
+                mod_delayed_work(system_nrt_freezable_wq, &ev->dwork, 0);
         spin_unlock_irq(&ev->lock);
 }
 
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 616d90bcb3a4..7c0df4af9ef7 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -538,7 +538,7 @@ static void edac_mc_workq_setup(struct mem_ctl_info *mci, unsigned msec)
                 return;
 
         INIT_DELAYED_WORK(&mci->work, edac_mc_workq_function);
-        queue_delayed_work(edac_workqueue, &mci->work, msecs_to_jiffies(msec));
+        mod_delayed_work(edac_workqueue, &mci->work, msecs_to_jiffies(msec));
 }
 
 /*
@@ -578,21 +578,6 @@ void edac_mc_reset_delay_period(int value)
 
         mutex_lock(&mem_ctls_mutex);
 
-        /* scan the list and turn off all workq timers, doing so under lock
-         */
-        list_for_each(item, &mc_devices) {
-                mci = list_entry(item, struct mem_ctl_info, link);
-
-                if (mci->op_state == OP_RUNNING_POLL)
-                        cancel_delayed_work(&mci->work);
-        }
-
-        mutex_unlock(&mem_ctls_mutex);
-
-
-        /* re-walk the list, and reset the poll delay */
-        mutex_lock(&mem_ctls_mutex);
-
         list_for_each(item, &mc_devices) {
                 mci = list_entry(item, struct mem_ctl_info, link);
 
diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c
index 28058ae33d38..eaec8d7a3b73 100644
--- a/drivers/infiniband/core/addr.c
+++ b/drivers/infiniband/core/addr.c
@@ -152,13 +152,11 @@ static void set_timeout(unsigned long time)
 {
         unsigned long delay;
 
-        cancel_delayed_work(&work);
-
         delay = time - jiffies;
         if ((long)delay <= 0)
                 delay = 1;
 
-        queue_delayed_work(addr_wq, &work, delay);
+        mod_delayed_work(addr_wq, &work, delay);
 }
 
 static void queue_req(struct addr_req *req)
diff --git a/drivers/infiniband/hw/nes/nes_hw.c b/drivers/infiniband/hw/nes/nes_hw.c
index d42c9f435b1b..9e0895b45eb8 100644
--- a/drivers/infiniband/hw/nes/nes_hw.c
+++ b/drivers/infiniband/hw/nes/nes_hw.c
@@ -2679,11 +2679,9 @@ static void nes_process_mac_intr(struct nes_device *nesdev, u32 mac_number)
                         }
                 }
                 if (nesadapter->phy_type[mac_index] == NES_PHY_TYPE_SFP_D) {
-                        if (nesdev->link_recheck)
-                                cancel_delayed_work(&nesdev->work);
                         nesdev->link_recheck = 1;
-                        schedule_delayed_work(&nesdev->work,
-                                              NES_LINK_RECHECK_DELAY);
+                        mod_delayed_work(system_wq, &nesdev->work,
+                                         NES_LINK_RECHECK_DELAY);
                 }
         }
 
diff --git a/drivers/infiniband/hw/nes/nes_nic.c b/drivers/infiniband/hw/nes/nes_nic.c
index f3a3ecf8d09e..e43f6e41a6bd 100644
--- a/drivers/infiniband/hw/nes/nes_nic.c
+++ b/drivers/infiniband/hw/nes/nes_nic.c
@@ -243,10 +243,9 @@ static int nes_netdev_open(struct net_device *netdev)
 
         spin_lock_irqsave(&nesdev->nesadapter->phy_lock, flags);
         if (nesdev->nesadapter->phy_type[nesdev->mac_index] == NES_PHY_TYPE_SFP_D) {
-                if (nesdev->link_recheck)
-                        cancel_delayed_work(&nesdev->work);
                 nesdev->link_recheck = 1;
-                schedule_delayed_work(&nesdev->work, NES_LINK_RECHECK_DELAY);
+                mod_delayed_work(system_wq, &nesdev->work,
+                                 NES_LINK_RECHECK_DELAY);
         }
         spin_unlock_irqrestore(&nesdev->nesadapter->phy_lock, flags);
 
diff --git a/drivers/net/wireless/ipw2x00/ipw2100.c b/drivers/net/wireless/ipw2x00/ipw2100.c
index 95aa8e1683ec..8a3420257eeb 100644
--- a/drivers/net/wireless/ipw2x00/ipw2100.c
+++ b/drivers/net/wireless/ipw2x00/ipw2100.c
@@ -2180,8 +2180,7 @@ static void isr_indicate_rf_kill(struct ipw2100_priv *priv, u32 status)
 
         /* Make sure the RF Kill check timer is running */
         priv->stop_rf_kill = 0;
-        cancel_delayed_work(&priv->rf_kill);
-        schedule_delayed_work(&priv->rf_kill, round_jiffies_relative(HZ));
+        mod_delayed_work(system_wq, &priv->rf_kill, round_jiffies_relative(HZ));
 }
 
 static void send_scan_event(void *data)
@@ -4321,9 +4320,8 @@ static int ipw_radio_kill_sw(struct ipw2100_priv *priv, int disable_radio)
                                           "disabled by HW switch\n");
                         /* Make sure the RF_KILL check timer is running */
                         priv->stop_rf_kill = 0;
-                        cancel_delayed_work(&priv->rf_kill);
-                        schedule_delayed_work(&priv->rf_kill,
-                                              round_jiffies_relative(HZ));
+                        mod_delayed_work(system_wq, &priv->rf_kill,
+                                         round_jiffies_relative(HZ));
                 } else
                         schedule_reset(priv);
         }
diff --git a/drivers/net/wireless/zd1211rw/zd_usb.c b/drivers/net/wireless/zd1211rw/zd_usb.c
index af83c43bcdb1..ef2b171e3514 100644
--- a/drivers/net/wireless/zd1211rw/zd_usb.c
+++ b/drivers/net/wireless/zd1211rw/zd_usb.c
@@ -1164,8 +1164,7 @@ void zd_usb_reset_rx_idle_timer(struct zd_usb *usb)
 {
         struct zd_usb_rx *rx = &usb->rx;
 
-        cancel_delayed_work(&rx->idle_work);
-        queue_delayed_work(zd_workqueue, &rx->idle_work, ZD_RX_IDLE_INTERVAL);
+        mod_delayed_work(zd_workqueue, &rx->idle_work, ZD_RX_IDLE_INTERVAL);
 }
 
 static inline void init_usb_interrupt(struct zd_usb *usb)
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index e7f73287636c..06d2502ffb37 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -7682,25 +7682,15 @@ static int fan_set_speed(int speed)
 
 static void fan_watchdog_reset(void)
 {
-        static int fan_watchdog_active;
-
         if (fan_control_access_mode == TPACPI_FAN_WR_NONE)
                 return;
 
-        if (fan_watchdog_active)
-                cancel_delayed_work(&fan_watchdog_task);
-
         if (fan_watchdog_maxinterval > 0 &&
-            tpacpi_lifecycle != TPACPI_LIFE_EXITING) {
-                fan_watchdog_active = 1;
-                if (!queue_delayed_work(tpacpi_wq, &fan_watchdog_task,
-                                msecs_to_jiffies(fan_watchdog_maxinterval
-                                                 * 1000))) {
-                        pr_err("failed to queue the fan watchdog, "
-                               "watchdog will not trigger\n");
-                }
-        } else
-                fan_watchdog_active = 0;
+            tpacpi_lifecycle != TPACPI_LIFE_EXITING)
+                mod_delayed_work(tpacpi_wq, &fan_watchdog_task,
+                        msecs_to_jiffies(fan_watchdog_maxinterval * 1000));
+        else
+                cancel_delayed_work(&fan_watchdog_task);
 }
 
 static void fan_watchdog_fire(struct work_struct *ignored)
diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c
index 526e5c931294..7ff83cf43c8c 100644
--- a/drivers/power/charger-manager.c
+++ b/drivers/power/charger-manager.c
@@ -509,9 +509,8 @@ static void _setup_polling(struct work_struct *work)
         if (!delayed_work_pending(&cm_monitor_work) ||
             (delayed_work_pending(&cm_monitor_work) &&
              time_after(next_polling, _next_polling))) {
-                cancel_delayed_work_sync(&cm_monitor_work);
                 next_polling = jiffies + polling_jiffy;
-                queue_delayed_work(cm_wq, &cm_monitor_work, polling_jiffy);
+                mod_delayed_work(cm_wq, &cm_monitor_work, polling_jiffy);
         }
 
 out:
@@ -546,10 +545,8 @@ static void fullbatt_handler(struct charger_manager *cm)
         if (cm_suspended)
                 device_set_wakeup_capable(cm->dev, true);
 
-        if (delayed_work_pending(&cm->fullbatt_vchk_work))
-                cancel_delayed_work(&cm->fullbatt_vchk_work);
-        queue_delayed_work(cm_wq, &cm->fullbatt_vchk_work,
-                           msecs_to_jiffies(desc->fullbatt_vchkdrop_ms));
+        mod_delayed_work(cm_wq, &cm->fullbatt_vchk_work,
+                         msecs_to_jiffies(desc->fullbatt_vchkdrop_ms));
         cm->fullbatt_vchk_jiffies_at = jiffies + msecs_to_jiffies(
                                        desc->fullbatt_vchkdrop_ms);
 
diff --git a/drivers/power/ds2760_battery.c b/drivers/power/ds2760_battery.c
index 076e211a40b7..704e652072be 100644
--- a/drivers/power/ds2760_battery.c
+++ b/drivers/power/ds2760_battery.c
@@ -355,8 +355,7 @@ static void ds2760_battery_external_power_changed(struct power_supply *psy)
 
         dev_dbg(di->dev, "%s\n", __func__);
 
-        cancel_delayed_work(&di->monitor_work);
-        queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
+        mod_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
 }
 
 
@@ -401,8 +400,7 @@ static void ds2760_battery_set_charged(struct power_supply *psy)
 
         /* postpone the actual work by 20 secs. This is for debouncing GPIO
          * signals and to let the current value settle. See AN4188. */
-        cancel_delayed_work(&di->set_charged_work);
-        queue_delayed_work(di->monitor_wqueue, &di->set_charged_work, HZ * 20);
+        mod_delayed_work(di->monitor_wqueue, &di->set_charged_work, HZ * 20);
 }
 
 static int ds2760_battery_get_property(struct power_supply *psy,
@@ -616,8 +614,7 @@ static int ds2760_battery_resume(struct platform_device *pdev)
         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
         power_supply_changed(&di->bat);
 
-        cancel_delayed_work(&di->monitor_work);
-        queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
+        mod_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
 
         return 0;
 }
diff --git a/drivers/power/jz4740-battery.c b/drivers/power/jz4740-battery.c
index 8dbc7bfaab14..ffbed5e5b945 100644
--- a/drivers/power/jz4740-battery.c
+++ b/drivers/power/jz4740-battery.c
@@ -173,16 +173,14 @@ static void jz_battery_external_power_changed(struct power_supply *psy)
 {
         struct jz_battery *jz_battery = psy_to_jz_battery(psy);
 
-        cancel_delayed_work(&jz_battery->work);
-        schedule_delayed_work(&jz_battery->work, 0);
+        mod_delayed_work(system_wq, &jz_battery->work, 0);
 }
 
 static irqreturn_t jz_battery_charge_irq(int irq, void *data)
 {
         struct jz_battery *jz_battery = data;
 
-        cancel_delayed_work(&jz_battery->work);
-        schedule_delayed_work(&jz_battery->work, 0);
+        mod_delayed_work(system_wq, &jz_battery->work, 0);
 
         return IRQ_HANDLED;
 }
diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 2ab31e4f02cc..67789b8345d2 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -694,17 +694,14 @@ thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 static void thermal_zone_device_set_polling(struct thermal_zone_device *tz,
                                             int delay)
 {
-        cancel_delayed_work(&(tz->poll_queue));
-
-        if (!delay)
-                return;
-
         if (delay > 1000)
-                queue_delayed_work(system_freezable_wq, &(tz->poll_queue),
-                                      round_jiffies(msecs_to_jiffies(delay)));
+                mod_delayed_work(system_freezable_wq, &tz->poll_queue,
+                                 round_jiffies(msecs_to_jiffies(delay)));
+        else if (delay)
+                mod_delayed_work(system_freezable_wq, &tz->poll_queue,
+                                 msecs_to_jiffies(delay));
         else
-                queue_delayed_work(system_freezable_wq, &(tz->poll_queue),
-                                      msecs_to_jiffies(delay));
+                cancel_delayed_work(&tz->poll_queue);
 }
 
 static void thermal_zone_device_passive(struct thermal_zone_device *tz,
diff --git a/fs/afs/callback.c b/fs/afs/callback.c
index 587ef5123cd8..7ef637d7f3a5 100644
--- a/fs/afs/callback.c
+++ b/fs/afs/callback.c
@@ -351,9 +351,7 @@ void afs_dispatch_give_up_callbacks(struct work_struct *work)
  */
 void afs_flush_callback_breaks(struct afs_server *server)
 {
-        cancel_delayed_work(&server->cb_break_work);
-        queue_delayed_work(afs_callback_update_worker,
-                           &server->cb_break_work, 0);
+        mod_delayed_work(afs_callback_update_worker, &server->cb_break_work, 0);
 }
 
 #if 0
diff --git a/fs/afs/server.c b/fs/afs/server.c
index d59b7516e943..f342acf3547d 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -285,12 +285,7 @@ static void afs_reap_server(struct work_struct *work)
                 expiry = server->time_of_death + afs_server_timeout;
                 if (expiry > now) {
                         delay = (expiry - now) * HZ;
-                        if (!queue_delayed_work(afs_wq, &afs_server_reaper,
-                                                delay)) {
-                                cancel_delayed_work(&afs_server_reaper);
-                                queue_delayed_work(afs_wq, &afs_server_reaper,
-                                                   delay);
-                        }
+                        mod_delayed_work(afs_wq, &afs_server_reaper, delay);
                         break;
                 }
 
@@ -323,6 +318,5 @@ static void afs_reap_server(struct work_struct *work)
 void __exit afs_purge_servers(void)
 {
         afs_server_timeout = 0;
-        cancel_delayed_work(&afs_server_reaper);
-        queue_delayed_work(afs_wq, &afs_server_reaper, 0);
+        mod_delayed_work(afs_wq, &afs_server_reaper, 0);
 }
diff --git a/fs/afs/vlocation.c b/fs/afs/vlocation.c
index 431984d2e372..57bcb1596530 100644
--- a/fs/afs/vlocation.c
+++ b/fs/afs/vlocation.c
@@ -561,12 +561,7 @@ static void afs_vlocation_reaper(struct work_struct *work)
                 if (expiry > now) {
                         delay = (expiry - now) * HZ;
                         _debug("delay %lu", delay);
-                        if (!queue_delayed_work(afs_wq, &afs_vlocation_reap,
-                                                delay)) {
-                                cancel_delayed_work(&afs_vlocation_reap);
-                                queue_delayed_work(afs_wq, &afs_vlocation_reap,
-                                                   delay);
-                        }
+                        mod_delayed_work(afs_wq, &afs_vlocation_reap, delay);
                         break;
                 }
 
@@ -614,13 +609,10 @@ void afs_vlocation_purge(void)
         spin_lock(&afs_vlocation_updates_lock);
         list_del_init(&afs_vlocation_updates);
         spin_unlock(&afs_vlocation_updates_lock);
-        cancel_delayed_work(&afs_vlocation_update);
-        queue_delayed_work(afs_vlocation_update_worker,
-                           &afs_vlocation_update, 0);
+        mod_delayed_work(afs_vlocation_update_worker, &afs_vlocation_update, 0);
         destroy_workqueue(afs_vlocation_update_worker);
 
-        cancel_delayed_work(&afs_vlocation_reap);
-        queue_delayed_work(afs_wq, &afs_vlocation_reap, 0);
+        mod_delayed_work(afs_wq, &afs_vlocation_reap, 0);
 }
 
 /*
diff --git a/fs/nfs/nfs4renewd.c b/fs/nfs/nfs4renewd.c
index 6930bec91bca..1720d32ffa54 100644
--- a/fs/nfs/nfs4renewd.c
+++ b/fs/nfs/nfs4renewd.c
@@ -117,8 +117,7 @@ nfs4_schedule_state_renewal(struct nfs_client *clp)
                 timeout = 5 * HZ;
         dprintk("%s: requeueing work. Lease period = %ld\n",
                         __func__, (timeout + HZ - 1) / HZ);
-        cancel_delayed_work(&clp->cl_renewd);
-        schedule_delayed_work(&clp->cl_renewd, timeout);
+        mod_delayed_work(system_wq, &clp->cl_renewd, timeout);
         set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
         spin_unlock(&clp->cl_lock);
 }
diff --git a/net/core/dst.c b/net/core/dst.c
index 069d51d29414..ed5a0b409aa3 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -214,8 +214,8 @@ void __dst_free(struct dst_entry *dst)
         if (dst_garbage.timer_inc > DST_GC_INC) {
                 dst_garbage.timer_inc = DST_GC_INC;
                 dst_garbage.timer_expires = DST_GC_MIN;
-                cancel_delayed_work(&dst_gc_work);
-                schedule_delayed_work(&dst_gc_work, dst_garbage.timer_expires);
+                mod_delayed_work(system_wq, &dst_gc_work,
+                                 dst_garbage.timer_expires);
         }
         spin_unlock_bh(&dst_garbage.lock);
 }
diff --git a/net/rfkill/input.c b/net/rfkill/input.c
index 24c55c53e6a2..c9d931e7ffec 100644
--- a/net/rfkill/input.c
+++ b/net/rfkill/input.c
@@ -164,8 +164,7 @@ static void rfkill_schedule_global_op(enum rfkill_sched_op op)
         rfkill_op_pending = true;
         if (op == RFKILL_GLOBAL_OP_EPO && !rfkill_is_epo_lock_active()) {
                 /* bypass the limiter for EPO */
-                cancel_delayed_work(&rfkill_op_work);
-                schedule_delayed_work(&rfkill_op_work, 0);
+                mod_delayed_work(system_wq, &rfkill_op_work, 0);
                 rfkill_last_scheduled = jiffies;
         } else
                 rfkill_schedule_ratelimited();