workqueue: replace WORK_CPU_NONE/LAST with WORK_CPU_END

Now that workqueue has moved away from gcwqs, workqueue no longer has
the need to have a CPU identifier indicating "no cpu associated" - we
now use WORK_OFFQ_POOL_NONE instead - and most uses of WORK_CPU_NONE
are gone.

The only left usage is as the end marker for for_each_*wq*()
iterators, where the name WORK_CPU_NONE is confusing w/o actual
WORK_CPU_NONE usages.  Similarly, WORK_CPU_LAST which equals
WORK_CPU_NONE no longer makes sense.

Replace both WORK_CPU_NONE and LAST with WORK_CPU_END.  This patch
doesn't introduce any functional difference.

tj: s/WORK_CPU_LAST/WORK_CPU_END/ and rewrote the description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

include/linux/workqueue.h

@@ -57,8 +57,7 @@ enum {
 
 	/* special cpu IDs */
 	WORK_CPU_UNBOUND	= NR_CPUS,
-	WORK_CPU_NONE		= NR_CPUS + 1,
-	WORK_CPU_LAST		= WORK_CPU_NONE,
+	WORK_CPU_END		= NR_CPUS + 1,
 
 	/*
 	 * Reserve 7 bits off of cwq pointer w/ debugobjects turned

kernel/workqueue.c

@@ -258,7 +258,7 @@ static inline int __next_wq_cpu(int cpu, const struct cpumask *mask,
 		if (sw & 2)
 			return WORK_CPU_UNBOUND;
 	}
-	return WORK_CPU_NONE;
+	return WORK_CPU_END;
 }
 
 static inline int __next_cwq_cpu(int cpu, const struct cpumask *mask,
@@ -282,17 +282,17 @@ static inline int __next_cwq_cpu(int cpu, const struct cpumask *mask,
  */
 #define for_each_wq_cpu(cpu)						\
 	for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, 3);		\
-	     (cpu) < WORK_CPU_NONE;					\
+	     (cpu) < WORK_CPU_END;					\
 	     (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, 3))
 
 #define for_each_online_wq_cpu(cpu)					\
 	for ((cpu) = __next_wq_cpu(-1, cpu_online_mask, 3);		\
-	     (cpu) < WORK_CPU_NONE;					\
+	     (cpu) < WORK_CPU_END;					\
 	     (cpu) = __next_wq_cpu((cpu), cpu_online_mask, 3))
 
 #define for_each_cwq_cpu(cpu, wq)					\
 	for ((cpu) = __next_cwq_cpu(-1, cpu_possible_mask, (wq));	\
-	     (cpu) < WORK_CPU_NONE;					\
+	     (cpu) < WORK_CPU_END;					\
 	     (cpu) = __next_cwq_cpu((cpu), cpu_possible_mask, (wq)))
 
 #ifdef CONFIG_DEBUG_OBJECTS_WORK
@@ -3796,7 +3796,7 @@ static int __init init_workqueues(void)
 
 	/* make sure we have enough bits for OFFQ pool ID */
 	BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT)) <
-		     WORK_CPU_LAST * NR_STD_WORKER_POOLS);
+		     WORK_CPU_END * NR_STD_WORKER_POOLS);
 
 	cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP);
 	hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN);