[PATCH] revert "kthread: convert stop_machine into a kthread"

Jiri reports that the stop_machin kthread conversion caused his machine to
hang when suspending.  Hyperthreading is apparently involved.

I don't see why that would be and I can't reproduce it.  Revert to the 2.6.17
code.

Cc: "Serge E. Hallyn" <serue@us.ibm.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 11 deletions

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 2c0aacc37c55..dcfb5d731466 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -4,7 +4,6 @@
 #include <linux/cpu.h>
 #include <linux/err.h>
 #include <linux/syscalls.h>
-#include <linux/kthread.h>
 #include <asm/atomic.h>
 #include <asm/semaphore.h>
 #include <asm/uaccess.h>
@@ -26,11 +25,13 @@ static unsigned int stopmachine_num_threads;
 static atomic_t stopmachine_thread_ack;
 static DECLARE_MUTEX(stopmachine_mutex);
 
-static int stopmachine(void *unused)
+static int stopmachine(void *cpu)
 {
         int irqs_disabled = 0;
         int prepared = 0;
 
+        set_cpus_allowed(current, cpumask_of_cpu((int)(long)cpu));
+
         /* Ack: we are alive */
         smp_mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */
         atomic_inc(&stopmachine_thread_ack);
@@ -84,8 +85,7 @@ static void stopmachine_set_state(enum stopmachine_state state)
 
 static int stop_machine(void)
 {
-        int ret = 0;
-        unsigned int i;
+        int i, ret = 0;
         struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 
         /* One high-prio thread per cpu.  We'll do this one. */
@@ -96,16 +96,11 @@ static int stop_machine(void)
         stopmachine_state = STOPMACHINE_WAIT;
 
         for_each_online_cpu(i) {
-                struct task_struct *tsk;
                 if (i == raw_smp_processor_id())
                         continue;
-                tsk = kthread_create(stopmachine, NULL, "stopmachine");
-                if (IS_ERR(tsk)) {
-                        ret = PTR_ERR(tsk);
+                ret = kernel_thread(stopmachine, (void *)(long)i,CLONE_KERNEL);
+                if (ret < 0)
                         break;
-                }
-                kthread_bind(tsk, i);
-                wake_up_process(tsk);
                 stopmachine_num_threads++;
         }