kthread: kthread worker API cleanup

A good practice is to prefix the names of functions by the name
of the subsystem.

The kthread worker API is a mix of classic kthreads and workqueues.  Each
worker has a dedicated kthread.  It runs a generic function that process
queued works.  It is implemented as part of the kthread subsystem.

This patch renames the existing kthread worker API to use
the corresponding name from the workqueues API prefixed by
kthread_:

__init_kthread_worker()		-> __kthread_init_worker()
init_kthread_worker()		-> kthread_init_worker()
init_kthread_work()		-> kthread_init_work()
insert_kthread_work()		-> kthread_insert_work()
queue_kthread_work()		-> kthread_queue_work()
flush_kthread_work()		-> kthread_flush_work()
flush_kthread_worker()		-> kthread_flush_worker()

Note that the names of DEFINE_KTHREAD_WORK*() macros stay
as they are. It is common that the "DEFINE_" prefix has
precedence over the subsystem names.

Note that INIT() macros and init() functions use different
naming scheme. There is no good solution. There are several
reasons for this solution:

  + "init" in the function names stands for the verb "initialize"
    aka "initialize worker". While "INIT" in the macro names
    stands for the noun "INITIALIZER" aka "worker initializer".

  + INIT() macros are used only in DEFINE() macros

  + init() functions are used close to the other kthread()
    functions. It looks much better if all the functions
    use the same scheme.

  + There will be also kthread_destroy_worker() that will
    be used close to kthread_cancel_work(). It is related
    to the init() function. Again it looks better if all
    functions use the same naming scheme.

  + there are several precedents for such init() function
    names, e.g. amd_iommu_init_device(), free_area_init_node(),
    jump_label_init_type(),  regmap_init_mmio_clk(),

  + It is not an argument but it was inconsistent even before.

[arnd@arndb.de: fix linux-next merge conflict]
 Link: http://lkml.kernel.org/r/20160908135724.1311726-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1470754545-17632-3-git-send-email-pmladek@suse.com
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/spi/spi.c

@@ -1112,7 +1112,7 @@ static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
 
 	/* If another context is idling the device then defer */
 	if (master->idling) {
-		queue_kthread_work(&master->kworker, &master->pump_messages);
+		kthread_queue_work(&master->kworker, &master->pump_messages);
 		spin_unlock_irqrestore(&master->queue_lock, flags);
 		return;
 	}
@@ -1126,7 +1126,7 @@ static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
 
 		/* Only do teardown in the thread */
 		if (!in_kthread) {
-			queue_kthread_work(&master->kworker,
+			kthread_queue_work(&master->kworker,
 					   &master->pump_messages);
 			spin_unlock_irqrestore(&master->queue_lock, flags);
 			return;
@@ -1250,7 +1250,7 @@ static int spi_init_queue(struct spi_master *master)
 	master->running = false;
 	master->busy = false;
 
-	init_kthread_worker(&master->kworker);
+	kthread_init_worker(&master->kworker);
 	master->kworker_task = kthread_run(kthread_worker_fn,
 					   &master->kworker, "%s",
 					   dev_name(&master->dev));
@@ -1258,7 +1258,7 @@ static int spi_init_queue(struct spi_master *master)
 		dev_err(&master->dev, "failed to create message pump task\n");
 		return PTR_ERR(master->kworker_task);
 	}
-	init_kthread_work(&master->pump_messages, spi_pump_messages);
+	kthread_init_work(&master->pump_messages, spi_pump_messages);
 
 	/*
 	 * Master config will indicate if this controller should run the
@@ -1331,7 +1331,7 @@ void spi_finalize_current_message(struct spi_master *master)
 	spin_lock_irqsave(&master->queue_lock, flags);
 	master->cur_msg = NULL;
 	master->cur_msg_prepared = false;
-	queue_kthread_work(&master->kworker, &master->pump_messages);
+	kthread_queue_work(&master->kworker, &master->pump_messages);
 	spin_unlock_irqrestore(&master->queue_lock, flags);
 
 	trace_spi_message_done(mesg);
@@ -1357,7 +1357,7 @@ static int spi_start_queue(struct spi_master *master)
 	master->cur_msg = NULL;
 	spin_unlock_irqrestore(&master->queue_lock, flags);
 
-	queue_kthread_work(&master->kworker, &master->pump_messages);
+	kthread_queue_work(&master->kworker, &master->pump_messages);
 
 	return 0;
 }
@@ -1404,7 +1404,7 @@ static int spi_destroy_queue(struct spi_master *master)
 	ret = spi_stop_queue(master);
 
 	/*
-	 * flush_kthread_worker will block until all work is done.
+	 * kthread_flush_worker will block until all work is done.
 	 * If the reason that stop_queue timed out is that the work will never
 	 * finish, then it does no good to call flush/stop thread, so
 	 * return anyway.
@@ -1414,7 +1414,7 @@ static int spi_destroy_queue(struct spi_master *master)
 		return ret;
 	}
 
-	flush_kthread_worker(&master->kworker);
+	kthread_flush_worker(&master->kworker);
 	kthread_stop(master->kworker_task);
 
 	return 0;
@@ -1438,7 +1438,7 @@ static int __spi_queued_transfer(struct spi_device *spi,
 
 	list_add_tail(&msg->queue, &master->queue);
 	if (!master->busy && need_pump)
-		queue_kthread_work(&master->kworker, &master->pump_messages);
+		kthread_queue_work(&master->kworker, &master->pump_messages);
 
 	spin_unlock_irqrestore(&master->queue_lock, flags);
 	return 0;