[PATCH] alpha: IPI update [2/10]

- send_ipi_message() fix from Jeff Wiedemeier:
  The 2.5.30 IPI algorithm (with the to_whom == set test) incorrectly sends
  IPI messages to CPU 0 in a SMP system running with one processor. In this
  case to_whom is often 0 (cpu_present_mask & ~1UL << smp_processor_id()) which
  ends up triggering the to_whom == set case.
- migration IPI removed;

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 41c904b7515df62c709f299b56dfe86d4870dd70..9b5d8a2cdff55376361f3fb8564504a75559d732 100644 (file)
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -62,7 +62,6 @@ static struct {
 
 enum ipi_message_type {
        IPI_RESCHEDULE,
-       IPI_MIGRATION,
        IPI_CALL_FUNC,
        IPI_CPU_STOP,
 };
@@ -668,33 +667,21 @@ send_ipi_message(unsigned long to_whom, enum ipi_message_type operation)
 {
        unsigned long i, set, n;
 
-       set = to_whom & -to_whom;
-       if (to_whom == set) {
+       mb();
+       for (i = to_whom; i ; i &= ~set) {
+               set = i & -i;
                n = __ffs(set);
-               mb();
                set_bit(operation, &ipi_data[n].bits);
-               mb();
-               wripir(n);
-       } else {
-               mb();
-               for (i = to_whom; i ; i &= ~set) {
-                       set = i & -i;
-                       n = __ffs(set);
-                       set_bit(operation, &ipi_data[n].bits);
-               }
+       }
 
-               mb();
-               for (i = to_whom; i ; i &= ~set) {
-                       set = i & -i;
-                       n = __ffs(set);
-                       wripir(n);
-               }
+       mb();
+       for (i = to_whom; i ; i &= ~set) {
+               set = i & -i;
+               n = __ffs(set);
+               wripir(n);
        }
 }
 
-/* Data for IPI_MIGRATION.  */
-static task_t *migration_task;
-
 /* Structure and data for smp_call_function.  This is designed to 
    minimize static memory requirements.  Plus it looks cleaner.  */
 
@@ -768,15 +755,6 @@ handle_ipi(struct pt_regs *regs)
                           is done by the interrupt return path.  */
                        break;
 
-               case IPI_MIGRATION:
-                   {
-                       task_t *t = migration_task;
-                       mb();
-                       migration_task = 0;
-                       sched_task_migrated(t);
-                       break;
-                   }
-
                case IPI_CALL_FUNC:
                    {
                        struct smp_call_struct *data;
@@ -834,19 +812,6 @@ smp_send_reschedule(int cpu)
        send_ipi_message(1UL << cpu, IPI_RESCHEDULE);
 }
 
-void
-smp_migrate_task(int cpu, task_t *t)
-{
-#if DEBUG_IPI_MSG
-       if (cpu == hard_smp_processor_id())
-               printk(KERN_WARNING
-                      "smp_migrate_task: Sending IPI to self.\n");
-#endif
-       /* Acquire the migration_task mutex.  */
-       pointer_lock(&migration_task, t, 1);
-       send_ipi_message(1UL << cpu, IPI_MIGRATION);
-}
-
 void
 smp_send_stop(void)
 {