1 files changed, 117 insertions, 187 deletions

diff --git a/kernel/async.c b/kernel/async.c
index 15319d6c18fe..61f023ce0228 100644
--- a/kernel/async.c
+++ b/kernel/async.c
@@ -49,97 +49,74 @@ asynchronous and synchronous parts of the kernel.
 */
 
 #include <linux/async.h>
-#include <linux/bug.h>
-#include <linux/module.h>
+#include <linux/atomic.h>
+#include <linux/ktime.h>
+#include <linux/export.h>
 #include <linux/wait.h>
 #include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/kthread.h>
-#include <linux/delay.h>
 #include <linux/slab.h>
-#include <asm/atomic.h>
+#include <linux/workqueue.h>
+
+#include "workqueue_internal.h"
 
 static async_cookie_t next_cookie = 1;
 
-#define MAX_THREADS	256
-#define MAX_WORK	32768
+#define MAX_WORK		32768
+#define ASYNC_COOKIE_MAX	ULLONG_MAX	/* infinity cookie */
 
-static LIST_HEAD(async_pending);
-static LIST_HEAD(async_running);
+static LIST_HEAD(async_global_pending);	/* pending from all registered doms */
+static ASYNC_DOMAIN(async_dfl_domain);
 static DEFINE_SPINLOCK(async_lock);
 
-static int async_enabled = 0;
-
 struct async_entry {
-	struct list_head list;
-	async_cookie_t   cookie;
-	async_func_ptr	 *func;
-	void             *data;
-	struct list_head *running;
+	struct list_head	domain_list;
+	struct list_head	global_list;
+	struct work_struct	work;
+	async_cookie_t		cookie;
+	async_func_t		func;
+	void			*data;
+	struct async_domain	*domain;
 };
 
 static DECLARE_WAIT_QUEUE_HEAD(async_done);
-static DECLARE_WAIT_QUEUE_HEAD(async_new);
 
 static atomic_t entry_count;
-static atomic_t thread_count;
-
-extern int initcall_debug;
-
 
-/*
- * MUST be called with the lock held!
- */
-static async_cookie_t  __lowest_in_progress(struct list_head *running)
+static async_cookie_t lowest_in_progress(struct async_domain *domain)
 {
-	struct async_entry *entry;
-
-	if (!list_empty(running)) {
-		entry = list_first_entry(running,
-			struct async_entry, list);
-		return entry->cookie;
-	}
+	struct list_head *pending;
+	async_cookie_t ret = ASYNC_COOKIE_MAX;
+	unsigned long flags;
 
-	list_for_each_entry(entry, &async_pending, list)
-		if (entry->running == running)
-			return entry->cookie;
+	spin_lock_irqsave(&async_lock, flags);
 
-	return next_cookie;	/* "infinity" value */
-}
+	if (domain)
+		pending = &domain->pending;
+	else
+		pending = &async_global_pending;
 
-static async_cookie_t  lowest_in_progress(struct list_head *running)
-{
-	unsigned long flags;
-	async_cookie_t ret;
+	if (!list_empty(pending))
+		ret = list_first_entry(pending, struct async_entry,
+				       domain_list)->cookie;
 
-	spin_lock_irqsave(&async_lock, flags);
-	ret = __lowest_in_progress(running);
 	spin_unlock_irqrestore(&async_lock, flags);
 	return ret;
 }
+
 /*
  * pick the first pending entry and run it
  */
-static void run_one_entry(void)
+static void async_run_entry_fn(struct work_struct *work)
 {
+	struct async_entry *entry =
+		container_of(work, struct async_entry, work);
 	unsigned long flags;
-	struct async_entry *entry;
-	ktime_t calltime, delta, rettime;
-
-	/* 1) pick one task from the pending queue */
-
-	spin_lock_irqsave(&async_lock, flags);
-	if (list_empty(&async_pending))
-		goto out;
-	entry = list_first_entry(&async_pending, struct async_entry, list);
+	ktime_t uninitialized_var(calltime), delta, rettime;
 
-	/* 2) move it to the running queue */
-	list_move_tail(&entry->list, entry->running);
-	spin_unlock_irqrestore(&async_lock, flags);
-
-	/* 3) run it (and print duration)*/
+	/* 1) run (and print duration) */
 	if (initcall_debug && system_state == SYSTEM_BOOTING) {
-		printk("calling  %lli_%pF @ %i\n", (long long)entry->cookie,
+		printk(KERN_DEBUG "calling  %lli_%pF @ %i\n",
+			(long long)entry->cookie,
 			entry->func, task_pid_nr(current));
 		calltime = ktime_get();
 	}
@@ -147,37 +124,32 @@ static void run_one_entry(void)
 	if (initcall_debug && system_state == SYSTEM_BOOTING) {
 		rettime = ktime_get();
 		delta = ktime_sub(rettime, calltime);
-		printk("initcall %lli_%pF returned 0 after %lld usecs\n",
+		printk(KERN_DEBUG "initcall %lli_%pF returned 0 after %lld usecs\n",
 			(long long)entry->cookie,
 			entry->func,
 			(long long)ktime_to_ns(delta) >> 10);
 	}
 
-	/* 4) remove it from the running queue */
+	/* 2) remove self from the pending queues */
 	spin_lock_irqsave(&async_lock, flags);
-	list_del(&entry->list);
+	list_del_init(&entry->domain_list);
+	list_del_init(&entry->global_list);
 
-	/* 5) free the entry  */
+	/* 3) free the entry */
 	kfree(entry);
 	atomic_dec(&entry_count);
 
 	spin_unlock_irqrestore(&async_lock, flags);
 
-	/* 6) wake up any waiters. */
+	/* 4) wake up any waiters */
 	wake_up(&async_done);
-	return;
-
-out:
-	spin_unlock_irqrestore(&async_lock, flags);
 }
 
-
-static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct list_head *running)
+static async_cookie_t __async_schedule(async_func_t func, void *data, struct async_domain *domain)
 {
 	struct async_entry *entry;
 	unsigned long flags;
 	async_cookie_t newcookie;
-	
 
 	/* allow irq-off callers */
 	entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
@@ -186,59 +158,74 @@ static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct l
 	 * If we're out of memory or if there's too much work
 	 * pending already, we execute synchronously.
 	 */
-	if (!async_enabled || !entry || atomic_read(&entry_count) > MAX_WORK) {
+	if (!entry || atomic_read(&entry_count) > MAX_WORK) {
 		kfree(entry);
 		spin_lock_irqsave(&async_lock, flags);
 		newcookie = next_cookie++;
 		spin_unlock_irqrestore(&async_lock, flags);
 
 		/* low on memory.. run synchronously */
-		ptr(data, newcookie);
+		func(data, newcookie);
 		return newcookie;
 	}
-	entry->func = ptr;
+	INIT_LIST_HEAD(&entry->domain_list);
+	INIT_LIST_HEAD(&entry->global_list);
+	INIT_WORK(&entry->work, async_run_entry_fn);
+	entry->func = func;
 	entry->data = data;
-	entry->running = running;
+	entry->domain = domain;
 
 	spin_lock_irqsave(&async_lock, flags);
+
+	/* allocate cookie and queue */
 	newcookie = entry->cookie = next_cookie++;
-	list_add_tail(&entry->list, &async_pending);
+
+	list_add_tail(&entry->domain_list, &domain->pending);
+	if (domain->registered)
+		list_add_tail(&entry->global_list, &async_global_pending);
+
 	atomic_inc(&entry_count);
 	spin_unlock_irqrestore(&async_lock, flags);
-	wake_up(&async_new);
+
+	/* mark that this task has queued an async job, used by module init */
+	current->flags |= PF_USED_ASYNC;
+
+	/* schedule for execution */
+	queue_work(system_unbound_wq, &entry->work);
+
 	return newcookie;
 }
 
 /**
  * async_schedule - schedule a function for asynchronous execution
- * @ptr: function to execute asynchronously
+ * @func: function to execute asynchronously
  * @data: data pointer to pass to the function
  *
  * Returns an async_cookie_t that may be used for checkpointing later.
  * Note: This function may be called from atomic or non-atomic contexts.
  */
-async_cookie_t async_schedule(async_func_ptr *ptr, void *data)
+async_cookie_t async_schedule(async_func_t func, void *data)
 {
-	return __async_schedule(ptr, data, &async_running);
+	return __async_schedule(func, data, &async_dfl_domain);
 }
 EXPORT_SYMBOL_GPL(async_schedule);
 
 /**
  * async_schedule_domain - schedule a function for asynchronous execution within a certain domain
- * @ptr: function to execute asynchronously
+ * @func: function to execute asynchronously
  * @data: data pointer to pass to the function
- * @running: running list for the domain
+ * @domain: the domain
  *
  * Returns an async_cookie_t that may be used for checkpointing later.
- * @running may be used in the async_synchronize_*_domain() functions
- * to wait within a certain synchronization domain rather than globally.
- * A synchronization domain is specified via the running queue @running to use.
- * Note: This function may be called from atomic or non-atomic contexts.
+ * @domain may be used in the async_synchronize_*_domain() functions to
+ * wait within a certain synchronization domain rather than globally.  A
+ * synchronization domain is specified via @domain.  Note: This function
+ * may be called from atomic or non-atomic contexts.
  */
-async_cookie_t async_schedule_domain(async_func_ptr *ptr, void *data,
-				     struct list_head *running)
+async_cookie_t async_schedule_domain(async_func_t func, void *data,
+				     struct async_domain *domain)
 {
-	return __async_schedule(ptr, data, running);
+	return __async_schedule(func, data, domain);
 }
 EXPORT_SYMBOL_GPL(async_schedule_domain);
 
@@ -249,51 +236,66 @@ EXPORT_SYMBOL_GPL(async_schedule_domain);
  */
 void async_synchronize_full(void)
 {
-	do {
-		async_synchronize_cookie(next_cookie);
-	} while (!list_empty(&async_running) || !list_empty(&async_pending));
+	async_synchronize_full_domain(NULL);
 }
 EXPORT_SYMBOL_GPL(async_synchronize_full);
 
 /**
+ * async_unregister_domain - ensure no more anonymous waiters on this domain
+ * @domain: idle domain to flush out of any async_synchronize_full instances
+ *
+ * async_synchronize_{cookie|full}_domain() are not flushed since callers
+ * of these routines should know the lifetime of @domain
+ *
+ * Prefer ASYNC_DOMAIN_EXCLUSIVE() declarations over flushing
+ */
+void async_unregister_domain(struct async_domain *domain)
+{
+	spin_lock_irq(&async_lock);
+	WARN_ON(!domain->registered || !list_empty(&domain->pending));
+	domain->registered = 0;
+	spin_unlock_irq(&async_lock);
+}
+EXPORT_SYMBOL_GPL(async_unregister_domain);
+
+/**
  * async_synchronize_full_domain - synchronize all asynchronous function within a certain domain
- * @list: running list to synchronize on
+ * @domain: the domain to synchronize
  *
  * This function waits until all asynchronous function calls for the
- * synchronization domain specified by the running list @list have been done.
+ * synchronization domain specified by @domain have been done.
  */
-void async_synchronize_full_domain(struct list_head *list)
+void async_synchronize_full_domain(struct async_domain *domain)
 {
-	async_synchronize_cookie_domain(next_cookie, list);
+	async_synchronize_cookie_domain(ASYNC_COOKIE_MAX, domain);
 }
 EXPORT_SYMBOL_GPL(async_synchronize_full_domain);
 
 /**
  * async_synchronize_cookie_domain - synchronize asynchronous function calls within a certain domain with cookie checkpointing
  * @cookie: async_cookie_t to use as checkpoint
- * @running: running list to synchronize on
+ * @domain: the domain to synchronize (%NULL for all registered domains)
  *
  * This function waits until all asynchronous function calls for the
- * synchronization domain specified by the running list @list submitted
- * prior to @cookie have been done.
+ * synchronization domain specified by @domain submitted prior to @cookie
+ * have been done.
  */
-void async_synchronize_cookie_domain(async_cookie_t cookie,
-				     struct list_head *running)
+void async_synchronize_cookie_domain(async_cookie_t cookie, struct async_domain *domain)
 {
-	ktime_t starttime, delta, endtime;
+	ktime_t uninitialized_var(starttime), delta, endtime;
 
 	if (initcall_debug && system_state == SYSTEM_BOOTING) {
-		printk("async_waiting @ %i\n", task_pid_nr(current));
+		printk(KERN_DEBUG "async_waiting @ %i\n", task_pid_nr(current));
 		starttime = ktime_get();
 	}
 
-	wait_event(async_done, lowest_in_progress(running) >= cookie);
+	wait_event(async_done, lowest_in_progress(domain) >= cookie);
 
 	if (initcall_debug && system_state == SYSTEM_BOOTING) {
 		endtime = ktime_get();
 		delta = ktime_sub(endtime, starttime);
 
-		printk("async_continuing @ %i after %lli usec\n",
+		printk(KERN_DEBUG "async_continuing @ %i after %lli usec\n",
 			task_pid_nr(current),
 			(long long)ktime_to_ns(delta) >> 10);
 	}
@@ -309,90 +311,18 @@ EXPORT_SYMBOL_GPL(async_synchronize_cookie_domain);
  */
 void async_synchronize_cookie(async_cookie_t cookie)
 {
-	async_synchronize_cookie_domain(cookie, &async_running);
+	async_synchronize_cookie_domain(cookie, &async_dfl_domain);
 }
 EXPORT_SYMBOL_GPL(async_synchronize_cookie);
 
-
-static int async_thread(void *unused)
-{
-	DECLARE_WAITQUEUE(wq, current);
-	add_wait_queue(&async_new, &wq);
-
-	while (!kthread_should_stop()) {
-		int ret = HZ;
-		set_current_state(TASK_INTERRUPTIBLE);
-		/*
-		 * check the list head without lock.. false positives
-		 * are dealt with inside run_one_entry() while holding
-		 * the lock.
-		 */
-		rmb();
-		if (!list_empty(&async_pending))
-			run_one_entry();
-		else
-			ret = schedule_timeout(HZ);
-
-		if (ret == 0) {
-			/*
-			 * we timed out, this means we as thread are redundant.
-			 * we sign off and die, but we to avoid any races there
-			 * is a last-straw check to see if work snuck in.
-			 */
-			atomic_dec(&thread_count);
-			wmb(); /* manager must see our departure first */
-			if (list_empty(&async_pending))
-				break;
-			/*
-			 * woops work came in between us timing out and us
-			 * signing off; we need to stay alive and keep working.
-			 */
-			atomic_inc(&thread_count);
-		}
-	}
-	remove_wait_queue(&async_new, &wq);
-
-	return 0;
-}
-
-static int async_manager_thread(void *unused)
-{
-	DECLARE_WAITQUEUE(wq, current);
-	add_wait_queue(&async_new, &wq);
-
-	while (!kthread_should_stop()) {
-		int tc, ec;
-
-		set_current_state(TASK_INTERRUPTIBLE);
-
-		tc = atomic_read(&thread_count);
-		rmb();
-		ec = atomic_read(&entry_count);
-
-		while (tc < ec && tc < MAX_THREADS) {
-			if (IS_ERR(kthread_run(async_thread, NULL, "async/%i",
-					       tc))) {
-				msleep(100);
-				continue;
-			}
-			atomic_inc(&thread_count);
-			tc++;
-		}
-
-		schedule();
-	}
-	remove_wait_queue(&async_new, &wq);
-
-	return 0;
-}
-
-static int __init async_init(void)
+/**
+ * current_is_async - is %current an async worker task?
+ *
+ * Returns %true if %current is an async worker task.
+ */
+bool current_is_async(void)
 {
-	async_enabled =
-		!IS_ERR(kthread_run(async_manager_thread, NULL, "async/mgr"));
+	struct worker *worker = current_wq_worker();
 
-	WARN_ON(!async_enabled);
-	return 0;
+	return worker && worker->current_func == async_run_entry_fn;
 }
-
-core_initcall(async_init);