workqueue: use mod_delayed_work() instead of __cancel + queue

Now that mod_delayed_work() is safe to call from IRQ handlers,
__cancel_delayed_work() followed by queue_delayed_work() can be
replaced with mod_delayed_work().

Most conversions are straight-forward except for the following.

* net/core/link_watch.c: linkwatch_schedule_work() was doing a quite
  elaborate dancing around its delayed_work.  Collapse it such that
  linkwatch_work is queued for immediate execution if LW_URGENT and
  existing timer is kept otherwise.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> 

7 files changed, 17 insertions, 44 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 4b4dbdfbca89..4b8b606dbb01 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -319,10 +319,8 @@ EXPORT_SYMBOL(__blk_run_queue);
  */
 void blk_run_queue_async(struct request_queue *q)
 {
-        if (likely(!blk_queue_stopped(q))) {
-                __cancel_delayed_work(&q->delay_work);
-                queue_delayed_work(kblockd_workqueue, &q->delay_work, 0);
-        }
+        if (likely(!blk_queue_stopped(q)))
+                mod_delayed_work(kblockd_workqueue, &q->delay_work, 0);
 }
 EXPORT_SYMBOL(blk_run_queue_async);
 
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 5a58e779912b..a9664fa0b609 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -929,12 +929,7 @@ throtl_schedule_delayed_work(struct throtl_data *td, unsigned long delay)
 
         /* schedule work if limits changed even if no bio is queued */
         if (total_nr_queued(td) || td->limits_changed) {
-                /*
-                 * We might have a work scheduled to be executed in future.
-                 * Cancel that and schedule a new one.
-                 */
-                __cancel_delayed_work(dwork);
-                queue_delayed_work(kthrotld_workqueue, dwork, delay);
+                mod_delayed_work(kthrotld_workqueue, dwork, delay);
                 throtl_log(td, "schedule work. delay=%lu jiffies=%lu",
                                 delay, jiffies);
         }
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index a7d6347aaa79..55a5bc002c06 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -672,7 +672,6 @@ static void __reschedule_timeout(int drive, const char *message)
 
         if (drive == current_reqD)
                 drive = current_drive;
-        __cancel_delayed_work(&fd_timeout);
 
         if (drive < 0 || drive >= N_DRIVE) {
                 delay = 20UL * HZ;
@@ -680,7 +679,7 @@ static void __reschedule_timeout(int drive, const char *message)
         } else
                 delay = UDP->timeout;
 
-        queue_delayed_work(floppy_wq, &fd_timeout, delay);
+        mod_delayed_work(floppy_wq, &fd_timeout, delay);
         if (UDP->flags & FD_DEBUG)
                 DPRINT("reschedule timeout %s\n", message);
         timeout_message = message;
diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
index b0d0bc8a6fb6..b5938147fc89 100644
--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -2013,13 +2013,11 @@ static void adjust_timeout(struct ib_mad_agent_private *mad_agent_priv)
                 if (time_after(mad_agent_priv->timeout,
                                mad_send_wr->timeout)) {
                         mad_agent_priv->timeout = mad_send_wr->timeout;
-                        __cancel_delayed_work(&mad_agent_priv->timed_work);
                         delay = mad_send_wr->timeout - jiffies;
                         if ((long)delay <= 0)
                                 delay = 1;
-                        queue_delayed_work(mad_agent_priv->qp_info->
-                                           port_priv->wq,
-                                           &mad_agent_priv->timed_work, delay);
+                        mod_delayed_work(mad_agent_priv->qp_info->port_priv->wq,
+                                         &mad_agent_priv->timed_work, delay);
                 }
         }
 }
@@ -2052,11 +2050,9 @@ static void wait_for_response(struct ib_mad_send_wr_private *mad_send_wr)
         list_add(&mad_send_wr->agent_list, list_item);
 
         /* Reschedule a work item if we have a shorter timeout */
-        if (mad_agent_priv->wait_list.next == &mad_send_wr->agent_list) {
-                __cancel_delayed_work(&mad_agent_priv->timed_work);
-                queue_delayed_work(mad_agent_priv->qp_info->port_priv->wq,
-                                   &mad_agent_priv->timed_work, delay);
-        }
+        if (mad_agent_priv->wait_list.next == &mad_send_wr->agent_list)
+                mod_delayed_work(mad_agent_priv->qp_info->port_priv->wq,
+                                 &mad_agent_priv->timed_work, delay);
 }
 
 void ib_reset_mad_timeout(struct ib_mad_send_wr_private *mad_send_wr,
diff --git a/drivers/input/keyboard/qt2160.c b/drivers/input/keyboard/qt2160.c
index e7a5e36e1203..76b7d430d03a 100644
--- a/drivers/input/keyboard/qt2160.c
+++ b/drivers/input/keyboard/qt2160.c
@@ -156,8 +156,7 @@ static irqreturn_t qt2160_irq(int irq, void *_qt2160)
 
         spin_lock_irqsave(&qt2160->lock, flags);
 
-        __cancel_delayed_work(&qt2160->dwork);
-        schedule_delayed_work(&qt2160->dwork, 0);
+        mod_delayed_work(system_wq, &qt2160->dwork, 0);
 
         spin_unlock_irqrestore(&qt2160->lock, flags);
 
diff --git a/drivers/input/mouse/synaptics_i2c.c b/drivers/input/mouse/synaptics_i2c.c
index f14675702c0f..063a174d3a88 100644
--- a/drivers/input/mouse/synaptics_i2c.c
+++ b/drivers/input/mouse/synaptics_i2c.c
@@ -376,12 +376,7 @@ static void synaptics_i2c_reschedule_work(struct synaptics_i2c *touch,
 
         spin_lock_irqsave(&touch->lock, flags);
 
-        /*
-         * If work is already scheduled then subsequent schedules will not
-         * change the scheduled time that's why we have to cancel it first.
-         */
-        __cancel_delayed_work(&touch->dwork);
-        schedule_delayed_work(&touch->dwork, delay);
+        mod_delayed_work(system_wq, &touch->dwork, delay);
 
         spin_unlock_irqrestore(&touch->lock, flags);
 }
diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index c3519c6d1b16..8e397a69005a 100644
--- a/net/core/link_watch.c
+++ b/net/core/link_watch.c
@@ -120,22 +120,13 @@ static void linkwatch_schedule_work(int urgent)
                 delay = 0;
 
         /*
-         * This is true if we've scheduled it immeditately or if we don't
-         * need an immediate execution and it's already pending.
+         * If urgent, schedule immediate execution; otherwise, don't
+         * override the existing timer.
          */
-        if (schedule_delayed_work(&linkwatch_work, delay) == !delay)
-                return;
-
-        /* Don't bother if there is nothing urgent. */
-        if (!test_bit(LW_URGENT, &linkwatch_flags))
-                return;
-
-        /* It's already running which is good enough. */
-        if (!__cancel_delayed_work(&linkwatch_work))
-                return;
-
-        /* Otherwise we reschedule it again for immediate execution. */
-        schedule_delayed_work(&linkwatch_work, 0);
+        if (test_bit(LW_URGENT, &linkwatch_flags))
+                mod_delayed_work(system_wq, &linkwatch_work, 0);
+        else
+                schedule_delayed_work(&linkwatch_work, delay);
 }