Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff
[linux-2.6.git] / kernel / workqueue.c
index 259cf55..880fb41 100644 (file)
@@ -12,6 +12,8 @@
  *   Andrew Morton <andrewm@uow.edu.au>
  *   Kai Petzke <wpp@marie.physik.tu-berlin.de>
  *   Theodore Ts'o <tytso@mit.edu>
+ *
+ * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>.
  */
 
 #include <linux/module.h>
 #include <linux/cpu.h>
 #include <linux/notifier.h>
 #include <linux/kthread.h>
+#include <linux/hardirq.h>
 
 /*
- * The per-CPU workqueue (if single thread, we always use cpu 0's).
+ * The per-CPU workqueue (if single thread, we always use the first
+ * possible cpu).
  *
  * The sequence counters are for flush_scheduled_work().  It wants to wait
  * until until all currently-scheduled works are completed, but it doesn't
@@ -57,7 +61,7 @@ struct cpu_workqueue_struct {
  * per-CPU workqueues:
  */
 struct workqueue_struct {
-       struct cpu_workqueue_struct cpu_wq[NR_CPUS];
+       struct cpu_workqueue_struct *cpu_wq;
        const char *name;
        struct list_head list;  /* Empty if single thread */
 };
@@ -67,6 +71,8 @@ struct workqueue_struct {
 static DEFINE_SPINLOCK(workqueue_lock);
 static LIST_HEAD(workqueues);
 
+static int singlethread_cpu;
+
 /* If it's single threaded, it isn't in the list of workqueues. */
 static inline int is_single_threaded(struct workqueue_struct *wq)
 {
@@ -100,9 +106,9 @@ int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work)
 
        if (!test_and_set_bit(0, &work->pending)) {
                if (unlikely(is_single_threaded(wq)))
-                       cpu = 0;
+                       cpu = singlethread_cpu;
                BUG_ON(!list_empty(&work->entry));
-               __queue_work(wq->cpu_wq + cpu, work);
+               __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
                ret = 1;
        }
        put_cpu();
@@ -116,9 +122,9 @@ static void delayed_work_timer_fn(unsigned long __data)
        int cpu = smp_processor_id();
 
        if (unlikely(is_single_threaded(wq)))
-               cpu = 0;
+               cpu = singlethread_cpu;
 
-       __queue_work(wq->cpu_wq + cpu, work);
+       __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
 }
 
 int fastcall queue_delayed_work(struct workqueue_struct *wq,
@@ -142,7 +148,7 @@ int fastcall queue_delayed_work(struct workqueue_struct *wq,
        return ret;
 }
 
-static inline void run_workqueue(struct cpu_workqueue_struct *cwq)
+static void run_workqueue(struct cpu_workqueue_struct *cwq)
 {
        unsigned long flags;
 
@@ -264,14 +270,14 @@ void fastcall flush_workqueue(struct workqueue_struct *wq)
        might_sleep();
 
        if (is_single_threaded(wq)) {
-               /* Always use cpu 0's area. */
-               flush_cpu_workqueue(wq->cpu_wq + 0);
+               /* Always use first cpu's area. */
+               flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu));
        } else {
                int cpu;
 
                lock_cpu_hotplug();
                for_each_online_cpu(cpu)
-                       flush_cpu_workqueue(wq->cpu_wq + cpu);
+                       flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
                unlock_cpu_hotplug();
        }
 }
@@ -279,7 +285,7 @@ void fastcall flush_workqueue(struct workqueue_struct *wq)
 static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq,
                                                   int cpu)
 {
-       struct cpu_workqueue_struct *cwq = wq->cpu_wq + cpu;
+       struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
        struct task_struct *p;
 
        spin_lock_init(&cwq->lock);
@@ -308,19 +314,22 @@ struct workqueue_struct *__create_workqueue(const char *name,
        struct workqueue_struct *wq;
        struct task_struct *p;
 
-       BUG_ON(strlen(name) > 10);
-
-       wq = kmalloc(sizeof(*wq), GFP_KERNEL);
+       wq = kzalloc(sizeof(*wq), GFP_KERNEL);
        if (!wq)
                return NULL;
-       memset(wq, 0, sizeof(*wq));
+
+       wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct);
+       if (!wq->cpu_wq) {
+               kfree(wq);
+               return NULL;
+       }
 
        wq->name = name;
        /* We don't need the distraction of CPUs appearing and vanishing. */
        lock_cpu_hotplug();
        if (singlethread) {
                INIT_LIST_HEAD(&wq->list);
-               p = create_workqueue_thread(wq, 0);
+               p = create_workqueue_thread(wq, singlethread_cpu);
                if (!p)
                        destroy = 1;
                else
@@ -356,7 +365,7 @@ static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu)
        unsigned long flags;
        struct task_struct *p;
 
-       cwq = wq->cpu_wq + cpu;
+       cwq = per_cpu_ptr(wq->cpu_wq, cpu);
        spin_lock_irqsave(&cwq->lock, flags);
        p = cwq->thread;
        cwq->thread = NULL;
@@ -374,7 +383,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
        /* We don't need the distraction of CPUs appearing and vanishing. */
        lock_cpu_hotplug();
        if (is_single_threaded(wq))
-               cleanup_workqueue_thread(wq, 0);
+               cleanup_workqueue_thread(wq, singlethread_cpu);
        else {
                for_each_online_cpu(cpu)
                        cleanup_workqueue_thread(wq, cpu);
@@ -383,6 +392,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
                spin_unlock(&workqueue_lock);
        }
        unlock_cpu_hotplug();
+       free_percpu(wq->cpu_wq);
        kfree(wq);
 }
 
@@ -418,6 +428,25 @@ int schedule_delayed_work_on(int cpu,
        return ret;
 }
 
+int schedule_on_each_cpu(void (*func) (void *info), void *info)
+{
+       int cpu;
+       struct work_struct *work;
+
+       work = kmalloc(NR_CPUS * sizeof(struct work_struct), GFP_KERNEL);
+
+       if (!work)
+               return -ENOMEM;
+       for_each_online_cpu(cpu) {
+               INIT_WORK(work + cpu, func, info);
+               __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu),
+                               work + cpu);
+       }
+       flush_workqueue(keventd_wq);
+       kfree(work);
+       return 0;
+}
+
 void flush_scheduled_work(void)
 {
        flush_workqueue(keventd_wq);
@@ -448,6 +477,34 @@ void cancel_rearming_delayed_work(struct work_struct *work)
 }
 EXPORT_SYMBOL(cancel_rearming_delayed_work);
 
+/**
+ * execute_in_process_context - reliably execute the routine with user context
+ * @fn:                the function to execute
+ * @data:      data to pass to the function
+ * @ew:                guaranteed storage for the execute work structure (must
+ *             be available when the work executes)
+ *
+ * Executes the function immediately if process context is available,
+ * otherwise schedules the function for delayed execution.
+ *
+ * Returns:    0 - function was executed
+ *             1 - function was scheduled for execution
+ */
+int execute_in_process_context(void (*fn)(void *data), void *data,
+                              struct execute_work *ew)
+{
+       if (!in_interrupt()) {
+               fn(data);
+               return 0;
+       }
+
+       INIT_WORK(&ew->work, fn, data);
+       schedule_work(&ew->work);
+
+       return 1;
+}
+EXPORT_SYMBOL_GPL(execute_in_process_context);
+
 int keventd_up(void)
 {
        return keventd_wq != NULL;
@@ -461,7 +518,7 @@ int current_is_keventd(void)
 
        BUG_ON(!keventd_wq);
 
-       cwq = keventd_wq->cpu_wq + cpu;
+       cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
        if (current == cwq->thread)
                ret = 1;
 
@@ -473,7 +530,7 @@ int current_is_keventd(void)
 /* Take the work from this (downed) CPU. */
 static void take_over_work(struct workqueue_struct *wq, unsigned int cpu)
 {
-       struct cpu_workqueue_struct *cwq = wq->cpu_wq + cpu;
+       struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
        LIST_HEAD(list);
        struct work_struct *work;
 
@@ -484,13 +541,13 @@ static void take_over_work(struct workqueue_struct *wq, unsigned int cpu)
                printk("Taking work for %s\n", wq->name);
                work = list_entry(list.next,struct work_struct,entry);
                list_del(&work->entry);
-               __queue_work(wq->cpu_wq + smp_processor_id(), work);
+               __queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work);
        }
        spin_unlock_irq(&cwq->lock);
 }
 
 /* We're holding the cpucontrol mutex here */
-static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
+static int workqueue_cpu_callback(struct notifier_block *nfb,
                                  unsigned long action,
                                  void *hcpu)
 {
@@ -501,7 +558,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
        case CPU_UP_PREPARE:
                /* Create a new workqueue thread for it. */
                list_for_each_entry(wq, &workqueues, list) {
-                       if (create_workqueue_thread(wq, hotcpu) < 0) {
+                       if (!create_workqueue_thread(wq, hotcpu)) {
                                printk("workqueue for %i failed\n", hotcpu);
                                return NOTIFY_BAD;
                        }
@@ -511,16 +568,19 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
        case CPU_ONLINE:
                /* Kick off worker threads. */
                list_for_each_entry(wq, &workqueues, list) {
-                       kthread_bind(wq->cpu_wq[hotcpu].thread, hotcpu);
-                       wake_up_process(wq->cpu_wq[hotcpu].thread);
+                       struct cpu_workqueue_struct *cwq;
+
+                       cwq = per_cpu_ptr(wq->cpu_wq, hotcpu);
+                       kthread_bind(cwq->thread, hotcpu);
+                       wake_up_process(cwq->thread);
                }
                break;
 
        case CPU_UP_CANCELED:
                list_for_each_entry(wq, &workqueues, list) {
                        /* Unbind so it can run. */
-                       kthread_bind(wq->cpu_wq[hotcpu].thread,
-                                    smp_processor_id());
+                       kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread,
+                                    any_online_cpu(cpu_online_map));
                        cleanup_workqueue_thread(wq, hotcpu);
                }
                break;
@@ -539,6 +599,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
 
 void init_workqueues(void)
 {
+       singlethread_cpu = first_cpu(cpu_possible_map);
        hotcpu_notifier(workqueue_cpu_callback, 0);
        keventd_wq = create_workqueue("events");
        BUG_ON(!keventd_wq);