Merge to Fedora kernel-2.6.17-1.2187_FC5 patched with stable patch-2.6.17.13-vs2...

[linux-2.6.git] / kernel / stop_machine.c

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 9610403..51cacd1 100644 (file)
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -6,6 +6,7 @@
 #include <linux/syscalls.h>
 #include <asm/atomic.h>
 #include <asm/semaphore.h>
+#include <asm/uaccess.h>
 
 /* Since we effect priority and affinity (both of which are visible
  * to, and settable by outside processes) we do indirection via a
@@ -32,7 +33,7 @@ static int stopmachine(void *cpu)
        set_cpus_allowed(current, cpumask_of_cpu((int)(long)cpu));
 
        /* Ack: we are alive */
-       mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */
+       smp_mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */
        atomic_inc(&stopmachine_thread_ack);
 
        /* Simple state machine */
@@ -42,21 +43,26 @@ static int stopmachine(void *cpu)
                        local_irq_disable();
                        irqs_disabled = 1;
                        /* Ack: irqs disabled. */
-                       mb(); /* Must read state first. */
+                       smp_mb(); /* Must read state first. */
                        atomic_inc(&stopmachine_thread_ack);
                } else if (stopmachine_state == STOPMACHINE_PREPARE
                           && !prepared) {
                        /* Everyone is in place, hold CPU. */
                        preempt_disable();
                        prepared = 1;
-                       mb(); /* Must read state first. */
+                       smp_mb(); /* Must read state first. */
                        atomic_inc(&stopmachine_thread_ack);
                }
-               cpu_relax();
+               /* Yield in first stage: migration threads need to
+                * help our sisters onto their CPUs. */
+               if (!prepared && !irqs_disabled)
+                       yield();
+               else
+                       cpu_relax();
        }
 
        /* Ack: we are exiting. */
-       mb(); /* Must read state first. */
+       smp_mb(); /* Must read state first. */
        atomic_inc(&stopmachine_thread_ack);
 
        if (irqs_disabled)
@@ -71,7 +77,7 @@ static int stopmachine(void *cpu)
 static void stopmachine_set_state(enum stopmachine_state state)
 {
        atomic_set(&stopmachine_thread_ack, 0);
-       wmb();
+       smp_wmb();
        stopmachine_state = state;
        while (atomic_read(&stopmachine_thread_ack) != stopmachine_num_threads)
                cpu_relax();
@@ -83,14 +89,14 @@ static int stop_machine(void)
        struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 
        /* One high-prio thread per cpu.  We'll do this one. */
-       sys_sched_setscheduler(current->pid, SCHED_FIFO, &param);
+       sched_setscheduler(current, SCHED_FIFO, &param);
 
        atomic_set(&stopmachine_thread_ack, 0);
        stopmachine_num_threads = 0;
        stopmachine_state = STOPMACHINE_WAIT;
 
        for_each_online_cpu(i) {
-               if (i == smp_processor_id())
+               if (i == raw_smp_processor_id())
                        continue;
                ret = kernel_thread(stopmachine, (void *)(long)i,CLONE_KERNEL);
                if (ret < 0)
@@ -105,17 +111,15 @@ static int stop_machine(void)
        /* If some failed, kill them all. */
        if (ret < 0) {
                stopmachine_set_state(STOPMACHINE_EXIT);
-               up(&stopmachine_mutex);
                return ret;
        }
 
-       /* Don't schedule us away at this point, please. */
-       local_irq_disable();
-
        /* Now they are all started, make them hold the CPUs, ready. */
+       preempt_disable();
        stopmachine_set_state(STOPMACHINE_PREPARE);
 
        /* Make them disable irqs. */
+       local_irq_disable();
        stopmachine_set_state(STOPMACHINE_DISABLE_IRQ);
 
        return 0;
@@ -125,6 +129,7 @@ static void restart_machine(void)
 {
        stopmachine_set_state(STOPMACHINE_EXIT);
        local_irq_enable();
+       preempt_enable_no_resched();
 }
 
 struct stop_machine_data
@@ -172,7 +177,7 @@ struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
 
        /* If they don't care which CPU fn runs on, bind to any online one. */
        if (cpu == NR_CPUS)
-               cpu = smp_processor_id();
+               cpu = raw_smp_processor_id();
 
        p = kthread_create(do_stop, &smdata, "kstopmachine");
        if (!IS_ERR(p)) {