workqueue: Convert to state machine callbacks

Get rid of the prio ordering of the separate notifiers and use a proper state
callback pair.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153335.197083890@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

3 files changed, 8 insertions, 9 deletions

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index ca2dd865a34e..797d9c8e9a1b 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -55,15 +55,6 @@ extern ssize_t arch_cpu_release(const char *, size_t);
 #endif
 struct notifier_block;
 
-/*
- * CPU notifier priorities.
- */
-enum {
-        /* bring up workqueues before normal notifiers and down after */
-        CPU_PRI_WORKQUEUE_UP    = 5,
-        CPU_PRI_WORKQUEUE_DOWN  = -5,
-};
-
 #define CPU_ONLINE              0x0002 /* CPU (unsigned)v is up */
 #define CPU_UP_PREPARE          0x0003 /* CPU (unsigned)v coming up */
 #define CPU_UP_CANCELED         0x0004 /* CPU (unsigned)v NOT coming up */
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index acfeda137df8..60557a9e783d 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -12,6 +12,7 @@ enum cpuhp_state {
         CPUHP_PERF_BFIN,
         CPUHP_PERF_POWER,
         CPUHP_PERF_SUPERH,
+        CPUHP_WORKQUEUE_PREP,
         CPUHP_NOTIFY_PREPARE,
         CPUHP_BRINGUP_CPU,
         CPUHP_AP_IDLE_DEAD,
@@ -49,6 +50,7 @@ enum cpuhp_state {
         CPUHP_AP_PERF_S390_SF_ONLINE,
         CPUHP_AP_PERF_ARM_CCI_ONLINE,
         CPUHP_AP_PERF_ARM_CCN_ONLINE,
+        CPUHP_AP_WORKQUEUE_ONLINE,
         CPUHP_AP_NOTIFY_ONLINE,
         CPUHP_AP_ONLINE_DYN,
         CPUHP_AP_ONLINE_DYN_END         = CPUHP_AP_ONLINE_DYN + 30,
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index ca73c503b92a..26cc1df280d6 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -625,4 +625,10 @@ void wq_watchdog_touch(int cpu);
 static inline void wq_watchdog_touch(int cpu) { }
 #endif  /* CONFIG_WQ_WATCHDOG */
 
+#ifdef CONFIG_SMP
+int workqueue_prepare_cpu(unsigned int cpu);
+int workqueue_online_cpu(unsigned int cpu);
+int workqueue_offline_cpu(unsigned int cpu);
+#endif
+
 #endif