6 files changed, 76 insertions, 50 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index d61ba88f34e5..e882c6babf41 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -16,47 +16,76 @@
 #include <asm/semaphore.h>
 
 /* This protects CPUs going up and down... */
-DECLARE_MUTEX(cpucontrol);
-EXPORT_SYMBOL_GPL(cpucontrol);
+static DECLARE_MUTEX(cpucontrol);
 
 static struct notifier_block *cpu_chain;
 
-/*
- * Used to check by callers if they need to acquire the cpucontrol
- * or not to protect a cpu from being removed. Its sometimes required to
- * call these functions both for normal operations, and in response to
- * a cpu being added/removed. If the context of the call is in the same
- * thread context as a CPU hotplug thread, we dont need to take the lock
- * since its already protected
- * check drivers/cpufreq/cpufreq.c for its usage - Ashok Raj
- */
+#ifdef CONFIG_HOTPLUG_CPU
+static struct task_struct *lock_cpu_hotplug_owner;
+static int lock_cpu_hotplug_depth;
 
-int current_in_cpu_hotplug(void)
+static int __lock_cpu_hotplug(int interruptible)
 {
-        return (current->flags & PF_HOTPLUG_CPU);
+        int ret = 0;
+
+        if (lock_cpu_hotplug_owner != current) {
+                if (interruptible)
+                        ret = down_interruptible(&cpucontrol);
+                else
+                        down(&cpucontrol);
+        }
+
+        /*
+         * Set only if we succeed in locking
+         */
+        if (!ret) {
+                lock_cpu_hotplug_depth++;
+                lock_cpu_hotplug_owner = current;
+        }
+
+        return ret;
 }
 
-EXPORT_SYMBOL_GPL(current_in_cpu_hotplug);
+void lock_cpu_hotplug(void)
+{
+        __lock_cpu_hotplug(0);
+}
+EXPORT_SYMBOL_GPL(lock_cpu_hotplug);
 
+void unlock_cpu_hotplug(void)
+{
+        if (--lock_cpu_hotplug_depth == 0) {
+                lock_cpu_hotplug_owner = NULL;
+                up(&cpucontrol);
+        }
+}
+EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);
+
+int lock_cpu_hotplug_interruptible(void)
+{
+        return __lock_cpu_hotplug(1);
+}
+EXPORT_SYMBOL_GPL(lock_cpu_hotplug_interruptible);
+#endif  /* CONFIG_HOTPLUG_CPU */
 
 /* Need to know about CPUs going up/down? */
 int register_cpu_notifier(struct notifier_block *nb)
 {
         int ret;
 
-        if ((ret = down_interruptible(&cpucontrol)) != 0)
+        if ((ret = lock_cpu_hotplug_interruptible()) != 0)
                 return ret;
         ret = notifier_chain_register(&cpu_chain, nb);
-        up(&cpucontrol);
+        unlock_cpu_hotplug();
         return ret;
 }
 EXPORT_SYMBOL(register_cpu_notifier);
 
 void unregister_cpu_notifier(struct notifier_block *nb)
 {
-        down(&cpucontrol);
+        lock_cpu_hotplug();
         notifier_chain_unregister(&cpu_chain, nb);
-        up(&cpucontrol);
+        unlock_cpu_hotplug();
 }
 EXPORT_SYMBOL(unregister_cpu_notifier);
 
@@ -112,13 +141,6 @@ int cpu_down(unsigned int cpu)
                 goto out;
         }
 
-        /*
-         * Leave a trace in current->flags indicating we are already in
-         * process of performing CPU hotplug. Callers can check if cpucontrol
-         * is already acquired by current thread, and if so not cause
-         * a dead lock by not acquiring the lock
-         */
-        current->flags |= PF_HOTPLUG_CPU;
         err = notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
                                                 (void *)(long)cpu);
         if (err == NOTIFY_BAD) {
@@ -171,7 +193,6 @@ out_thread:
 out_allowed:
         set_cpus_allowed(current, old_allowed);
 out:
-        current->flags &= ~PF_HOTPLUG_CPU;
         unlock_cpu_hotplug();
         return err;
 }
@@ -182,7 +203,7 @@ int __devinit cpu_up(unsigned int cpu)
         int ret;
         void *hcpu = (void *)(long)cpu;
 
-        if ((ret = down_interruptible(&cpucontrol)) != 0)
+        if ((ret = lock_cpu_hotplug_interruptible()) != 0)
                 return ret;
 
         if (cpu_online(cpu) || !cpu_present(cpu)) {
@@ -190,11 +211,6 @@ int __devinit cpu_up(unsigned int cpu)
                 goto out;
         }
 
-        /*
-         * Leave a trace in current->flags indicating we are already in
-         * process of performing CPU hotplug.
-         */
-        current->flags |= PF_HOTPLUG_CPU;
         ret = notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu);
         if (ret == NOTIFY_BAD) {
                 printk("%s: attempt to bring up CPU %u failed\n",
@@ -217,7 +233,6 @@ out_notify:
         if (ret != 0)
                 notifier_call_chain(&cpu_chain, CPU_UP_CANCELED, hcpu);
 out:
-        current->flags &= ~PF_HOTPLUG_CPU;
-        up(&cpucontrol);
+        unlock_cpu_hotplug();
         return ret;
 }
diff --git a/kernel/fork.c b/kernel/fork.c
index 1c1cf8dc396b..fb8572a42297 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1124,8 +1124,6 @@ static task_t *copy_process(unsigned long clone_flags,
         if (unlikely(p->ptrace & PT_PTRACED))
                 __ptrace_link(p, current->parent);
 
-        cpuset_fork(p);
-
         attach_pid(p, PIDTYPE_PID, p->pid);
         attach_pid(p, PIDTYPE_TGID, p->tgid);
         if (thread_group_leader(p)) {
@@ -1135,13 +1133,14 @@ static task_t *copy_process(unsigned long clone_flags,
                         __get_cpu_var(process_counts)++;
         }
 
-        proc_fork_connector(p);
         if (!current->signal->tty && p->signal->tty)
                 p->signal->tty = NULL;
 
         nr_threads++;
         total_forks++;
         write_unlock_irq(&tasklist_lock);
+        proc_fork_connector(p);
+        cpuset_fork(p);
         retval = 0;
 
 fork_out:
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 84af54c39e1b..cae4f5728997 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -36,7 +36,7 @@ timespec_to_sample(clockid_t which_clock, const struct timespec *tp)
         union cpu_time_count ret;
         ret.sched = 0;          /* high half always zero when .cpu used */
         if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
-                ret.sched = tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
+                ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
         } else {
                 ret.cpu = timespec_to_cputime(tp);
         }
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 6ee2cad530e8..d253f3ae2fa5 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -24,7 +24,7 @@
 
 DECLARE_MUTEX(pm_sem);
 
-struct pm_ops * pm_ops = NULL;
+struct pm_ops *pm_ops;
 suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
 
 /**
@@ -151,6 +151,18 @@ static char *pm_states[PM_SUSPEND_MAX] = {
 #endif
 };
 
+static inline int valid_state(suspend_state_t state)
+{
+        /* Suspend-to-disk does not really need low-level support.
+         * It can work with reboot if needed. */
+        if (state == PM_SUSPEND_DISK)
+                return 1;
+
+        if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
+                return 0;
+        return 1;
+}
+
 
 /**
  *      enter_state - Do common work of entering low-power state.
@@ -167,7 +179,7 @@ static int enter_state(suspend_state_t state)
 {
         int error;
 
-        if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
+        if (!valid_state(state))
                 return -ENODEV;
         if (down_trylock(&pm_sem))
                 return -EBUSY;
@@ -238,9 +250,8 @@ static ssize_t state_show(struct subsystem * subsys, char * buf)
         char * s = buf;
 
         for (i = 0; i < PM_SUSPEND_MAX; i++) {
-                if (pm_states[i] && pm_ops && (!pm_ops->valid
-                        ||(pm_ops->valid && pm_ops->valid(i))))
-                        s += sprintf(s,"%s ",pm_states[i]);
+                if (pm_states[i] && valid_state(i))
+                        s += sprintf(s,"%s ", pm_states[i]);
         }
         s += sprintf(s,"\n");
         return (s - buf);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 17ee7e5a3451..656476eedb1b 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -241,7 +241,8 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
                 if (write) {
                         copy_to_user_page(vma, page, addr,
                                           maddr + offset, buf, bytes);
-                        set_page_dirty_lock(page);
+                        if (!PageCompound(page))
+                                set_page_dirty_lock(page);
                 } else {
                         copy_from_user_page(vma, page, addr,
                                             buf, maddr + offset, bytes);
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 42df83d7fad2..2bd5aee1c736 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -102,7 +102,7 @@ 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 = any_online_cpu(cpu_online_map);
                 BUG_ON(!list_empty(&work->entry));
                 __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
                 ret = 1;
@@ -118,7 +118,7 @@ static void delayed_work_timer_fn(unsigned long __data)
         int cpu = smp_processor_id();
 
         if (unlikely(is_single_threaded(wq)))
-                cpu = 0;
+                cpu = any_online_cpu(cpu_online_map);
 
         __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
 }
@@ -266,8 +266,8 @@ void fastcall flush_workqueue(struct workqueue_struct *wq)
         might_sleep();
 
         if (is_single_threaded(wq)) {
-                /* Always use cpu 0's area. */
-                flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, 0));
+                /* Always use first cpu's area. */
+                flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, any_online_cpu(cpu_online_map)));
         } else {
                 int cpu;
 
@@ -320,7 +320,7 @@ struct workqueue_struct *__create_workqueue(const char *name,
         lock_cpu_hotplug();
         if (singlethread) {
                 INIT_LIST_HEAD(&wq->list);
-                p = create_workqueue_thread(wq, 0);
+                p = create_workqueue_thread(wq, any_online_cpu(cpu_online_map));
                 if (!p)
                         destroy = 1;
                 else
@@ -374,7 +374,7 @@ 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, any_online_cpu(cpu_online_map));
         else {
                 for_each_online_cpu(cpu)
                         cleanup_workqueue_thread(wq, cpu);