dm-delay: remove timer_lock

Instead of manually checking the timer details in queue_timeout(), call
timer_reduce() to start the timer or reduce the expiration time. This
avoids needing a lock.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index da3f8131d52c234af10cad6a708e2b0b5871acb6..08f6387620c1ceffe5aef3f44a66f74251eaeba5 100644 (file)
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -28,7 +28,6 @@ struct delay_class {
 
 struct delay_c {
        struct timer_list delay_timer;
-       struct mutex timer_lock;
        struct mutex process_bios_lock; /* hold while removing bios to be processed from list */
        spinlock_t delayed_bios_lock; /* hold on all accesses to delayed_bios list */
        struct workqueue_struct *kdelayd_wq;
@@ -60,12 +59,7 @@ static void handle_delayed_timer(struct timer_list *t)
 
 static void queue_timeout(struct delay_c *dc, unsigned long expires)
 {
-       mutex_lock(&dc->timer_lock);
-
-       if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires)
-               mod_timer(&dc->delay_timer, expires);
-
-       mutex_unlock(&dc->timer_lock);
+       timer_reduce(&dc->delay_timer, expires);
 }
 
 static inline bool delay_is_fast(struct delay_c *dc)
@@ -176,7 +170,6 @@ static void delay_dtr(struct dm_target *ti)
                kthread_stop(dc->worker);
 
        mutex_destroy(&dc->process_bios_lock);
-       mutex_destroy(&dc->timer_lock);
 
        kfree(dc);
 }
@@ -234,7 +227,6 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
        ti->private = dc;
        INIT_LIST_HEAD(&dc->delayed_bios);
-       mutex_init(&dc->timer_lock);
        mutex_init(&dc->process_bios_lock);
        spin_lock_init(&dc->delayed_bios_lock);
        dc->may_delay = true;