[PATCH] s390: Core changes

s390 core changes:
 - Fix mm_struct leak on cpu hotplug.
 - Improved cpu detection logic to avoid long delay at system start.
 - Call cpu_relax() in cpu hotplug wait loop.
 - Remove #define of account_system_vtime for CONFIG_VIRT_CPU_ACCOUNTING=n.
 - Regenerate default configuration.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/s390/defconfig

 #
 # Automatically generated make config: don't edit
-# Linux kernel version: 2.6.10
-# Mon Dec 27 11:03:23 2004
+# Linux kernel version: 2.6.11-rc1
+# Fri Jan 14 14:56:51 2005
 #
 CONFIG_MMU=y
 CONFIG_RWSEM_XCHGADD_ALGORITHM=y
+CONFIG_GENERIC_CALIBRATE_DELAY=y
 CONFIG_ARCH_S390=y
 CONFIG_UID16=y
 
@@ -142,6 +143,7 @@ CONFIG_SCSI_LOGGING=y
 #
 # CONFIG_SCSI_SPI_ATTRS is not set
 CONFIG_SCSI_FC_ATTRS=y
+# CONFIG_SCSI_ISCSI_ATTRS is not set
 
 #
 # SCSI low-level drivers
@@ -184,6 +186,7 @@ CONFIG_IOSCHED_NOOP=y
 CONFIG_IOSCHED_AS=y
 CONFIG_IOSCHED_DEADLINE=y
 CONFIG_IOSCHED_CFQ=y
+# CONFIG_ATA_OVER_ETH is not set
 
 #
 # Multi-device support (RAID and LVM)
@@ -530,6 +533,7 @@ CONFIG_MAGIC_SYSRQ=y
 # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
 # CONFIG_DEBUG_KOBJECT is not set
 # CONFIG_DEBUG_INFO is not set
+# CONFIG_DEBUG_FS is not set
 
 #
 # Security options

arch/s390/kernel/setup.c

@@ -98,6 +98,8 @@ void __devinit cpu_init (void)
         clear_thread_flag(TIF_USEDFPU);
         current->used_math = 0;
 
+	atomic_inc(&init_mm.mm_count);
+	current->active_mm = &init_mm;
         if (current->mm)
                 BUG();
         enter_lazy_tlb(&init_mm, current);

arch/s390/kernel/smp.c

@@ -486,48 +486,38 @@ void smp_ctl_clear_bit(int cr, int bit) {
  * Lets check how many CPUs we have.
  */
 
-#ifdef CONFIG_HOTPLUG_CPU
-
 void
 __init smp_check_cpus(unsigned int max_cpus)
 {
-	int cpu;
+	int cpu, num_cpus;
+	__u16 boot_cpu_addr;
 
 	/*
 	 * cpu 0 is the boot cpu. See smp_prepare_boot_cpu.
 	 */
-	for (cpu = 1; cpu < max_cpus; cpu++)
-		cpu_set(cpu, cpu_possible_map);
-}
-
-#else /* CONFIG_HOTPLUG_CPU */
-
-void
-__init smp_check_cpus(unsigned int max_cpus)
-{
-        int curr_cpu, num_cpus;
-	__u16 boot_cpu_addr;
 
 	boot_cpu_addr = S390_lowcore.cpu_data.cpu_addr;
+	__cpu_logical_map[0] = boot_cpu_addr;
 	current_thread_info()->cpu = 0;
 	num_cpus = 1;
-        for (curr_cpu = 0;
-             curr_cpu <= 65535 && num_cpus < max_cpus; curr_cpu++) {
-                if ((__u16) curr_cpu == boot_cpu_addr)
+	for (cpu = 0; cpu <= 65535 && num_cpus < max_cpus; cpu++) {
+		if ((__u16) cpu == boot_cpu_addr)
 			continue;
-                __cpu_logical_map[num_cpus] = (__u16) curr_cpu;
+		__cpu_logical_map[num_cpus] = (__u16) cpu;
 		if (signal_processor(num_cpus, sigp_sense) ==
 		    sigp_not_operational)
 			continue;
-		cpu_set(num_cpus, cpu_possible_map);
+		cpu_set(num_cpus, cpu_present_map);
 		num_cpus++;
 	}
+
+	for (cpu = 1; cpu < max_cpus; cpu++)
+		cpu_set(cpu, cpu_possible_map);
+
 	printk("Detected %d CPU's\n",(int) num_cpus);
 	printk("Boot cpu address %2X\n", boot_cpu_addr);
 }
 
-#endif /* CONFIG_HOTPLUG_CPU */
-
 /*
  *      Activate a secondary processor.
  */
@@ -571,8 +561,6 @@ static void __init smp_create_idle(unsigned int cpu)
 	p = fork_idle(cpu);
 	if (IS_ERR(p))
 		panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
-	atomic_inc(&init_mm.mm_count);
-	p->active_mm = &init_mm;
 	current_set[cpu] = p;
 }
 
@@ -681,7 +669,8 @@ __cpu_up(unsigned int cpu)
 	eieio();
 	signal_processor(cpu,sigp_restart);
 
-	while (!cpu_online(cpu));
+	while (!cpu_online(cpu))
+		cpu_relax();
 	return 0;
 }
 
@@ -736,13 +725,15 @@ void
 __cpu_die(unsigned int cpu)
 {
 	/* Wait until target cpu is down */
-	while (!cpu_stopped(cpu));
+	while (!cpu_stopped(cpu))
+		cpu_relax();
 	printk("Processor %d spun down\n", cpu);
 }
 
 void
 cpu_die(void)
 {
+	idle_task_exit();
 	signal_processor(smp_processor_id(), sigp_stop);
 	BUG();
 	for(;;);
@@ -806,6 +797,7 @@ void __devinit smp_prepare_boot_cpu(void)
 
 void smp_cpus_done(unsigned int max_cpus)
 {
+	cpu_present_map = cpu_possible_map;
 }
 
 /*

include/asm-s390/system.h

@@ -119,8 +119,6 @@ extern void account_system_vtime(struct task_struct *);
 
 #else
 
-#define account_system_vtime(prev)
-
 #define finish_arch_switch(rq, prev) do {				     \
 	set_fs(current->thread.mm_segment);				     \
 	spin_unlock_irq(&(rq)->lock);					     \