5 files changed, 55 insertions, 21 deletions

diff --git a/kernel/compat.c b/kernel/compat.c
index e167efce8423..c9e2ec0b34a8 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -1126,3 +1126,24 @@ compat_sys_sysinfo(struct compat_sysinfo __user *info)
 
         return 0;
 }
+
+/*
+ * Allocate user-space memory for the duration of a single system call,
+ * in order to marshall parameters inside a compat thunk.
+ */
+void __user *compat_alloc_user_space(unsigned long len)
+{
+        void __user *ptr;
+
+        /* If len would occupy more than half of the entire compat space... */
+        if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
+                return NULL;
+
+        ptr = arch_compat_alloc_user_space(len);
+
+        if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
+                return NULL;
+
+        return ptr;
+}
+EXPORT_SYMBOL_GPL(compat_alloc_user_space);
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index baae1367e945..c16158c77dfd 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3836,18 +3836,20 @@ static void perf_event_task_event(struct perf_task_event *task_event)
 
         rcu_read_lock();
         list_for_each_entry_rcu(pmu, &pmus, entry) {
-                cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+                cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
                 perf_event_task_ctx(&cpuctx->ctx, task_event);
 
                 ctx = task_event->task_ctx;
                 if (!ctx) {
                         ctxn = pmu->task_ctx_nr;
                         if (ctxn < 0)
-                                continue;
+                                goto next;
                         ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
                 }
                 if (ctx)
                         perf_event_task_ctx(ctx, task_event);
+next:
+                put_cpu_ptr(pmu->pmu_cpu_context);
         }
         rcu_read_unlock();
 }
@@ -3969,16 +3971,18 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event)
 
         rcu_read_lock();
         list_for_each_entry_rcu(pmu, &pmus, entry) {
-                cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+                cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
                 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
 
                 ctxn = pmu->task_ctx_nr;
                 if (ctxn < 0)
-                        continue;
+                        goto next;
 
                 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
                 if (ctx)
                         perf_event_comm_ctx(ctx, comm_event);
+next:
+                put_cpu_ptr(pmu->pmu_cpu_context);
         }
         rcu_read_unlock();
 }
@@ -4152,19 +4156,21 @@ got_name:
 
         rcu_read_lock();
         list_for_each_entry_rcu(pmu, &pmus, entry) {
-                cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+                cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
                 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
                                         vma->vm_flags & VM_EXEC);
 
                 ctxn = pmu->task_ctx_nr;
                 if (ctxn < 0)
-                        continue;
+                        goto next;
 
                 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
                 if (ctx) {
                         perf_event_mmap_ctx(ctx, mmap_event,
                                         vma->vm_flags & VM_EXEC);
                 }
+next:
+                put_cpu_ptr(pmu->pmu_cpu_context);
         }
         rcu_read_unlock();
 
diff --git a/kernel/sched.c b/kernel/sched.c
index 794819eab9ca..c0d2067f3e0d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3513,9 +3513,9 @@ void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
         rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
 
         if (total) {
-                u64 temp;
+                u64 temp = rtime;
 
-                temp = (u64)(rtime * utime);
+                temp *= utime;
                 do_div(temp, total);
                 utime = (cputime_t)temp;
         } else
@@ -3546,9 +3546,9 @@ void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
         rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
 
         if (total) {
-                u64 temp;
+                u64 temp = rtime;
 
-                temp = (u64)(rtime * cputime.utime);
+                temp *= cputime.utime;
                 do_div(temp, total);
                 utime = (cputime_t)temp;
         } else
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a171138a9402..db3f674ca49d 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -3630,7 +3630,7 @@ static inline int nohz_kick_needed(struct rq *rq, int cpu)
         if (time_before(now, nohz.next_balance))
                 return 0;
 
-        if (!rq->nr_running)
+        if (rq->idle_at_tick)
                 return 0;
 
         first_pick_cpu = atomic_read(&nohz.first_pick_cpu);
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 727f24e563ae..f77afd939229 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1,19 +1,26 @@
 /*
- * linux/kernel/workqueue.c
+ * kernel/workqueue.c - generic async execution with shared worker pool
  *
- * Generic mechanism for defining kernel helper threads for running
- * arbitrary tasks in process context.
+ * Copyright (C) 2002           Ingo Molnar
  *
- * Started by Ingo Molnar, Copyright (C) 2002
+ *   Derived from the taskqueue/keventd code by:
+ *     David Woodhouse <dwmw2@infradead.org>
+ *     Andrew Morton
+ *     Kai Petzke <wpp@marie.physik.tu-berlin.de>
+ *     Theodore Ts'o <tytso@mit.edu>
  *
- * Derived from the taskqueue/keventd code by:
+ * Made to use alloc_percpu by Christoph Lameter.
  *
- *   David Woodhouse <dwmw2@infradead.org>
- *   Andrew Morton
- *   Kai Petzke <wpp@marie.physik.tu-berlin.de>
- *   Theodore Ts'o <tytso@mit.edu>
+ * Copyright (C) 2010           SUSE Linux Products GmbH
+ * Copyright (C) 2010           Tejun Heo <tj@kernel.org>
  *
- * Made to use alloc_percpu by Christoph Lameter.
+ * This is the generic async execution mechanism.  Work items as are
+ * executed in process context.  The worker pool is shared and
+ * automatically managed.  There is one worker pool for each CPU and
+ * one extra for works which are better served by workers which are
+ * not bound to any specific CPU.
+ *
+ * Please read Documentation/workqueue.txt for details.
  */
 
 #include <linux/module.h>