lightnvm: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Matias Bjorling <mb@lightnvm.io>
Cc: linux-block@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
index 00d5698..9c8e114 100644
--- a/drivers/lightnvm/pblk-gc.c
+++ b/drivers/lightnvm/pblk-gc.c
@@ -442,9 +442,9 @@
 		goto next_gc_group;
 }
 
-static void pblk_gc_timer(unsigned long data)
+static void pblk_gc_timer(struct timer_list *t)
 {
-	struct pblk *pblk = (struct pblk *)data;
+	struct pblk *pblk = from_timer(pblk, t, gc.gc_timer);
 
 	pblk_gc_kick(pblk);
 }
@@ -601,7 +601,7 @@
 		goto fail_free_writer_kthread;
 	}
 
-	setup_timer(&gc->gc_timer, pblk_gc_timer, (unsigned long)pblk);
+	timer_setup(&gc->gc_timer, pblk_gc_timer, 0);
 	mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
 
 	gc->gc_active = 0;