[PATCH] more for_each_cpu() conversions

When we stop allocating percpu memory for not-possible CPUs we must not touch
the percpu data for not-possible CPUs at all.  The correct way of doing this
is to test cpu_possible() or to use for_each_cpu().

This patch is a kernel-wide sweep of all instances of NR_CPUS.  I found very
few instances of this bug, if any.  But the patch converts lots of open-coded
test to use the preferred helper macros.

Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Kyle McMartin <kyle@parisc-linux.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Christian Zankel <chris@zankel.net>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Jens Axboe <axboe@suse.de>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

42 files changed, 137 insertions, 222 deletions

diff --git a/arch/cris/kernel/irq.c b/arch/cris/kernel/irq.c
index 30deaf1b728a..b504def3e346 100644
--- a/arch/cris/kernel/irq.c
+++ b/arch/cris/kernel/irq.c
@@ -52,9 +52,8 @@ int show_interrupts(struct seq_file *p, void *v)
 
         if (i == 0) {
                 seq_printf(p, "           ");
-                for (j=0; j<NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "CPU%d       ",j);
+                for_each_online_cpu(j)
+                        seq_printf(p, "CPU%d       ",j);
                 seq_putc(p, '\n');
         }
 
@@ -67,9 +66,8 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 #endif
                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
                 seq_printf(p, "  %s", action->name);
diff --git a/arch/frv/kernel/irq.c b/arch/frv/kernel/irq.c
index 27ab4c30aac6..11fa326a8f62 100644
--- a/arch/frv/kernel/irq.c
+++ b/arch/frv/kernel/irq.c
@@ -75,9 +75,8 @@ int show_interrupts(struct seq_file *p, void *v)
         switch (i) {
         case 0:
                 seq_printf(p, "           ");
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "CPU%d       ",j);
+                for_each_online_cpu(j)
+                        seq_printf(p, "CPU%d       ",j);
 
                 seq_putc(p, '\n');
                 break;
@@ -100,9 +99,8 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ", kstat_cpu(j).irqs[i - 1]);
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", kstat_cpu(j).irqs[i - 1]);
 #endif
 
                 level = group->sources[ix]->level - frv_irq_levels;
diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
index e11a09207ec8..3d5110b65cc3 100644
--- a/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
@@ -1145,9 +1145,7 @@ static int __cpuinit powernowk8_init(void)
 {
         unsigned int i, supported_cpus = 0;
 
-        for (i=0; i<NR_CPUS; i++) {
-                if (!cpu_online(i))
-                        continue;
+        for_each_cpu(i) {
                 if (check_supported_cpu(i))
                         supported_cpus++;
         }
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index fd1c60cfd294..311b4e7266f1 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -351,8 +351,8 @@ static inline void rotate_irqs_among_cpus(unsigned long useful_load_threshold)
 {
         int i, j;
         Dprintk("Rotating IRQs among CPUs.\n");
-        for (i = 0; i < NR_CPUS; i++) {
-                for (j = 0; cpu_online(i) && (j < NR_IRQS); j++) {
+        for_each_online_cpu(i) {
+                for (j = 0; j < NR_IRQS; j++) {
                         if (!irq_desc[j].action)
                                 continue;
                         /* Is it a significant load ?  */
@@ -381,7 +381,7 @@ static void do_irq_balance(void)
         unsigned long imbalance = 0;
         cpumask_t allowed_mask, target_cpu_mask, tmp;
 
-        for (i = 0; i < NR_CPUS; i++) {
+        for_each_cpu(i) {
                 int package_index;
                 CPU_IRQ(i) = 0;
                 if (!cpu_online(i))
@@ -422,9 +422,7 @@ static void do_irq_balance(void)
                 }
         }
         /* Find the least loaded processor package */
-        for (i = 0; i < NR_CPUS; i++) {
-                if (!cpu_online(i))
-                        continue;
+        for_each_online_cpu(i) {
                 if (i != CPU_TO_PACKAGEINDEX(i))
                         continue;
                 if (min_cpu_irq > CPU_IRQ(i)) {
@@ -441,9 +439,7 @@ tryanothercpu:
          */
         tmp_cpu_irq = 0;
         tmp_loaded = -1;
-        for (i = 0; i < NR_CPUS; i++) {
-                if (!cpu_online(i))
-                        continue;
+        for_each_online_cpu(i) {
                 if (i != CPU_TO_PACKAGEINDEX(i))
                         continue;
                 if (max_cpu_irq <= CPU_IRQ(i)) 
@@ -619,9 +615,7 @@ static int __init balanced_irq_init(void)
         if (smp_num_siblings > 1 && !cpus_empty(tmp))
                 physical_balance = 1;
 
-        for (i = 0; i < NR_CPUS; i++) {
-                if (!cpu_online(i))
-                        continue;
+        for_each_online_cpu(i) {
                 irq_cpu_data[i].irq_delta = kmalloc(sizeof(unsigned long) * NR_IRQS, GFP_KERNEL);
                 irq_cpu_data[i].last_irq = kmalloc(sizeof(unsigned long) * NR_IRQS, GFP_KERNEL);
                 if (irq_cpu_data[i].irq_delta == NULL || irq_cpu_data[i].last_irq == NULL) {
@@ -638,9 +632,11 @@ static int __init balanced_irq_init(void)
         else 
                 printk(KERN_ERR "balanced_irq_init: failed to spawn balanced_irq");
 failed:
-        for (i = 0; i < NR_CPUS; i++) {
+        for_each_cpu(i) {
                 kfree(irq_cpu_data[i].irq_delta);
+                irq_cpu_data[i].irq_delta = NULL;
                 kfree(irq_cpu_data[i].last_irq);
+                irq_cpu_data[i].last_irq = NULL;
         }
         return 0;
 }
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index 1db34effdd8d..9074818b9473 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -143,7 +143,7 @@ static int __init check_nmi_watchdog(void)
         local_irq_enable();
         mdelay((10*1000)/nmi_hz); // wait 10 ticks
 
-        for (cpu = 0; cpu < NR_CPUS; cpu++) {
+        for_each_cpu(cpu) {
 #ifdef CONFIG_SMP
                 /* Check cpu_callin_map here because that is set
                    after the timer is started. */
@@ -510,7 +510,7 @@ void touch_nmi_watchdog (void)
          * Just reset the alert counters, (other CPUs might be
          * spinning on locks we hold):
          */
-        for (i = 0; i < NR_CPUS; i++)
+        for_each_cpu(i)
                 alert_counter[i] = 0;
 
         /*
diff --git a/arch/i386/oprofile/nmi_int.c b/arch/i386/oprofile/nmi_int.c
index 0493e8b8ec49..1accce50c2c7 100644
--- a/arch/i386/oprofile/nmi_int.c
+++ b/arch/i386/oprofile/nmi_int.c
@@ -122,7 +122,7 @@ static void nmi_save_registers(void * dummy)
 static void free_msrs(void)
 {
         int i;
-        for (i = 0; i < NR_CPUS; ++i) {
+        for_each_cpu(i) {
                 kfree(cpu_msrs[i].counters);
                 cpu_msrs[i].counters = NULL;
                 kfree(cpu_msrs[i].controls);
@@ -138,10 +138,7 @@ static int allocate_msrs(void)
         size_t counters_size = sizeof(struct op_msr) * model->num_counters;
 
         int i;
-        for (i = 0; i < NR_CPUS; ++i) {
-                if (!cpu_online(i))
-                        continue;
-
+        for_each_online_cpu(i) {
                 cpu_msrs[i].counters = kmalloc(counters_size, GFP_KERNEL);
                 if (!cpu_msrs[i].counters) {
                         success = 0;
diff --git a/arch/m32r/kernel/irq.c b/arch/m32r/kernel/irq.c
index 1ce63926a3c0..a4634b06f675 100644
--- a/arch/m32r/kernel/irq.c
+++ b/arch/m32r/kernel/irq.c
@@ -37,9 +37,8 @@ int show_interrupts(struct seq_file *p, void *v)
 
         if (i == 0) {
                 seq_printf(p, "           ");
-                for (j=0; j<NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "CPU%d       ",j);
+                for_each_online_cpu(j)
+                        seq_printf(p, "CPU%d       ",j);
                 seq_putc(p, '\n');
         }
 
@@ -52,9 +51,8 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 #endif
                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
                 seq_printf(p, "  %s", action->name);
diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
index 7d93992e462c..3dd76b3d2967 100644
--- a/arch/mips/kernel/irq.c
+++ b/arch/mips/kernel/irq.c
@@ -68,9 +68,8 @@ int show_interrupts(struct seq_file *p, void *v)
 
         if (i == 0) {
                 seq_printf(p, "           ");
-                for (j=0; j<NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "CPU%d       ",j);
+                for_each_online_cpu(j)
+                        seq_printf(p, "CPU%d       ",j);
                 seq_putc(p, '\n');
         }
 
@@ -83,9 +82,8 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 #endif
                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
                 seq_printf(p, "  %s", action->name);
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index 06ed90752424..78d171bfa331 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -167,8 +167,8 @@ int smp_call_function (void (*func) (void *info), void *info, int retry,
         mb();
 
         /* Send a message to all other CPUs and wait for them to respond */
-        for (i = 0; i < NR_CPUS; i++)
-                if (cpu_online(i) && i != cpu)
+        for_each_online_cpu(i)
+                if (i != cpu)
                         core_send_ipi(i, SMP_CALL_FUNCTION);
 
         /* Wait for response */
diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c
index 73e5e52781d8..2854ac4c9be1 100644
--- a/arch/mips/sgi-ip27/ip27-irq.c
+++ b/arch/mips/sgi-ip27/ip27-irq.c
@@ -88,12 +88,9 @@ static inline int find_level(cpuid_t *cpunum, int irq)
 {
         int cpu, i;
 
-        for (cpu = 0; cpu <= NR_CPUS; cpu++) {
+        for_each_online_cpu(cpu) {
                 struct slice_data *si = cpu_data[cpu].data;
 
-                if (!cpu_online(cpu))
-                        continue;
-
                 for (i = BASE_PCI_IRQ; i < LEVELS_PER_SLICE; i++)
                         if (si->level_to_irq[i] == irq) {
                                 *cpunum = cpu;
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 25564b7ca6bb..d6ac1c60a471 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -298,8 +298,8 @@ send_IPI_allbutself(enum ipi_message_type op)
 {
         int i;
         
-        for (i = 0; i < NR_CPUS; i++) {
-                if (cpu_online(i) && i != smp_processor_id())
+        for_each_online_cpu(i) {
+                if (i != smp_processor_id())
                         send_IPI_single(i, op);
         }
 }
@@ -643,14 +643,13 @@ int sys_cpus(int argc, char **argv)
         if ( argc == 1 ){
         
 #ifdef DUMP_MORE_STATE
-                for(i=0; i<NR_CPUS; i++) {
+                for_each_online_cpu(i) {
                         int cpus_per_line = 4;
-                        if(cpu_online(i)) {
-                                if (j++ % cpus_per_line)
-                                        printk(" %3d",i);
-                                else
-                                        printk("\n %3d",i);
-                        }
+
+                        if (j++ % cpus_per_line)
+                                printk(" %3d",i);
+                        else
+                                printk("\n %3d",i);
                 }
                 printk("\n"); 
 #else
@@ -659,9 +658,7 @@ int sys_cpus(int argc, char **argv)
         } else if((argc==2) && !(strcmp(argv[1],"-l"))) {
                 printk("\nCPUSTATE  TASK CPUNUM CPUID HARDCPU(HPA)\n");
 #ifdef DUMP_MORE_STATE
-                for(i=0;i<NR_CPUS;i++) {
-                        if (!cpu_online(i))
-                                continue;
+                for_each_online_cpu(i) {
                         if (cpu_data[i].cpuid != NO_PROC_ID) {
                                 switch(cpu_data[i].state) {
                                         case STATE_RENDEZVOUS:
@@ -695,9 +692,7 @@ int sys_cpus(int argc, char **argv)
         } else if ((argc==2) && !(strcmp(argv[1],"-s"))) { 
 #ifdef DUMP_MORE_STATE
                 printk("\nCPUSTATE   CPUID\n");
-                for (i=0;i<NR_CPUS;i++) {
-                        if (!cpu_online(i))
-                                continue;
+                for_each_online_cpu(i) {
                         if (cpu_data[i].cpuid != NO_PROC_ID) {
                                 switch(cpu_data[i].state) {
                                         case STATE_RENDEZVOUS:
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 24dc8117b822..771a59cbd213 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -135,9 +135,8 @@ skip:
 #ifdef CONFIG_TAU_INT
                 if (tau_initialized){
                         seq_puts(p, "TAU: ");
-                        for (j = 0; j < NR_CPUS; j++)
-                                if (cpu_online(j))
-                                        seq_printf(p, "%10u ", tau_interrupts(j));
+                        for_each_online_cpu(j)
+                                seq_printf(p, "%10u ", tau_interrupts(j));
                         seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
                 }
 #endif
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index be12041c0fc5..c1d62bf11f29 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -162,9 +162,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 #if defined(CONFIG_SMP) && defined(CONFIG_PPC32)
                 unsigned long bogosum = 0;
                 int i;
-                for (i = 0; i < NR_CPUS; ++i)
-                        if (cpu_online(i))
-                                bogosum += loops_per_jiffy;
+                for_each_online_cpu(i)
+                        bogosum += loops_per_jiffy;
                 seq_printf(m, "total bogomips\t: %lu.%02lu\n",
                            bogosum/(500000/HZ), bogosum/(5000/HZ) % 100);
 #endif /* CONFIG_SMP && CONFIG_PPC32 */
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index db72a92943bf..dc2770df25b3 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -272,9 +272,8 @@ int __init ppc_init(void)
         if ( ppc_md.progress ) ppc_md.progress("             ", 0xffff);
 
         /* register CPU devices */
-        for (i = 0; i < NR_CPUS; i++)
-                if (cpu_possible(i))
-                        register_cpu(&cpu_devices[i], i, NULL);
+        for_each_cpu(i)
+                register_cpu(&cpu_devices[i], i, NULL);
 
         /* call platform init */
         if (ppc_md.init != NULL) {
diff --git a/arch/powerpc/platforms/powermac/smp.c b/arch/powerpc/platforms/powermac/smp.c
index 6d64a9bf3474..1065d87fc279 100644
--- a/arch/powerpc/platforms/powermac/smp.c
+++ b/arch/powerpc/platforms/powermac/smp.c
@@ -191,9 +191,7 @@ static void smp_psurge_message_pass(int target, int msg)
         if (num_online_cpus() < 2)
                 return;
 
-        for (i = 0; i < NR_CPUS; i++) {
-                if (!cpu_online(i))
-                        continue;
+        for_each_online_cpu(i) {
                 if (target == MSG_ALL
                     || (target == MSG_ALL_BUT_SELF && i != smp_processor_id())
                     || target == i) {
diff --git a/arch/ppc/kernel/setup.c b/arch/ppc/kernel/setup.c
index c08ab432e958..53e9deacee82 100644
--- a/arch/ppc/kernel/setup.c
+++ b/arch/ppc/kernel/setup.c
@@ -168,9 +168,8 @@ int show_cpuinfo(struct seq_file *m, void *v)
                 /* Show summary information */
 #ifdef CONFIG_SMP
                 unsigned long bogosum = 0;
-                for (i = 0; i < NR_CPUS; ++i)
-                        if (cpu_online(i))
-                                bogosum += cpu_data[i].loops_per_jiffy;
+                for_each_online_cpu(i)
+                        bogosum += cpu_data[i].loops_per_jiffy;
                 seq_printf(m, "total bogomips\t: %lu.%02lu\n",
                            bogosum/(500000/HZ), bogosum/(5000/HZ) % 100);
 #endif /* CONFIG_SMP */
@@ -712,9 +711,8 @@ int __init ppc_init(void)
         if ( ppc_md.progress ) ppc_md.progress("             ", 0xffff);
 
         /* register CPU devices */
-        for (i = 0; i < NR_CPUS; i++)
-                if (cpu_possible(i))
-                        register_cpu(&cpu_devices[i], i, NULL);
+        for_each_cpu(i)
+                register_cpu(&cpu_devices[i], i, NULL);
 
         /* call platform init */
         if (ppc_md.init != NULL) {
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 7dbe00c76c6b..d52d6d211d9f 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -799,9 +799,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
          */
         print_cpu_info(&S390_lowcore.cpu_data);
 
-        for(i = 0; i < NR_CPUS; i++) {
-                if (!cpu_possible(i))
-                        continue;
+        for_each_cpu(i) {
                 lowcore_ptr[i] = (struct _lowcore *)
                         __get_free_pages(GFP_KERNEL|GFP_DMA, 
                                         sizeof(void*) == 8 ? 1 : 0);
diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index 6883c00728cb..b56e79632f24 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -35,9 +35,8 @@ int show_interrupts(struct seq_file *p, void *v)
 
         if (i == 0) {
                 seq_puts(p, "           ");
-                for (j=0; j<NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "CPU%d       ",j);
+                for_each_online_cpu(j)
+                        seq_printf(p, "CPU%d       ",j);
                 seq_putc(p, '\n');
         }
 
diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
index a067a34e0b64..c0e79843f580 100644
--- a/arch/sh/kernel/setup.c
+++ b/arch/sh/kernel/setup.c
@@ -404,9 +404,8 @@ static int __init topology_init(void)
 {
         int cpu_id;
 
-        for (cpu_id = 0; cpu_id < NR_CPUS; cpu_id++)
-                if (cpu_possible(cpu_id))
-                        register_cpu(&cpu[cpu_id], cpu_id, NULL);
+        for_each_cpu(cpu_id)
+                register_cpu(&cpu[cpu_id], cpu_id, NULL);
 
         return 0;
 }
diff --git a/arch/sh64/kernel/irq.c b/arch/sh64/kernel/irq.c
index 9fc2b71dbd84..d69879c0e063 100644
--- a/arch/sh64/kernel/irq.c
+++ b/arch/sh64/kernel/irq.c
@@ -53,9 +53,8 @@ int show_interrupts(struct seq_file *p, void *v)
 
         if (i == 0) {
                 seq_puts(p, "           ");
-                for (j=0; j<NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "CPU%d       ",j);
+                for_each_online_cpu(j)
+                        seq_printf(p, "CPU%d       ",j);
                 seq_putc(p, '\n');
         }
 
diff --git a/arch/sparc/kernel/irq.c b/arch/sparc/kernel/irq.c
index 410b9a72aba9..4c60a6ef54a9 100644
--- a/arch/sparc/kernel/irq.c
+++ b/arch/sparc/kernel/irq.c
@@ -184,9 +184,8 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (j = 0; j < NR_CPUS; j++) {
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ",
+                for_each_online_cpu(j) {
+                        seq_printf(p, "%10u ",
                                     kstat_cpu(cpu_logical_map(j)).irqs[i]);
                 }
 #endif
diff --git a/arch/sparc/kernel/smp.c b/arch/sparc/kernel/smp.c
index c6e721d8f477..ea5682ce7031 100644
--- a/arch/sparc/kernel/smp.c
+++ b/arch/sparc/kernel/smp.c
@@ -243,9 +243,8 @@ int setup_profiling_timer(unsigned int multiplier)
                 return -EINVAL;
 
         spin_lock_irqsave(&prof_setup_lock, flags);
-        for(i = 0; i < NR_CPUS; i++) {
-                if (cpu_possible(i))
-                        load_profile_irq(i, lvl14_resolution / multiplier);
+        for_each_cpu(i) {
+                load_profile_irq(i, lvl14_resolution / multiplier);
                 prof_multiplier(i) = multiplier;
         }
         spin_unlock_irqrestore(&prof_setup_lock, flags);
@@ -273,13 +272,12 @@ void smp_bogo(struct seq_file *m)
 {
         int i;
         
-        for (i = 0; i < NR_CPUS; i++) {
-                if (cpu_online(i))
-                        seq_printf(m,
-                                   "Cpu%dBogo\t: %lu.%02lu\n", 
-                                   i,
-                                   cpu_data(i).udelay_val/(500000/HZ),
-                                   (cpu_data(i).udelay_val/(5000/HZ))%100);
+        for_each_online_cpu(i) {
+                seq_printf(m,
+                           "Cpu%dBogo\t: %lu.%02lu\n",
+                           i,
+                           cpu_data(i).udelay_val/(500000/HZ),
+                           (cpu_data(i).udelay_val/(5000/HZ))%100);
         }
 }
 
@@ -288,8 +286,6 @@ void smp_info(struct seq_file *m)
         int i;
 
         seq_printf(m, "State:\n");
-        for (i = 0; i < NR_CPUS; i++) {
-                if (cpu_online(i))
-                        seq_printf(m, "CPU%d\t\t: online\n", i);
-        }
+        for_each_online_cpu(i)
+                seq_printf(m, "CPU%d\t\t: online\n", i);
 }
diff --git a/arch/sparc/kernel/sun4d_irq.c b/arch/sparc/kernel/sun4d_irq.c
index 52621348a56c..cea7fc6fc6e5 100644
--- a/arch/sparc/kernel/sun4d_irq.c
+++ b/arch/sparc/kernel/sun4d_irq.c
@@ -103,11 +103,9 @@ found_it:	seq_printf(p, "%3d: ", i);
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (x = 0; x < NR_CPUS; x++) {
-                        if (cpu_online(x))
-                                seq_printf(p, "%10u ",
-                                       kstat_cpu(cpu_logical_map(x)).irqs[i]);
-                }
+                for_each_online_cpu(x)
+                        seq_printf(p, "%10u ",
+                               kstat_cpu(cpu_logical_map(x)).irqs[i]);
 #endif
                 seq_printf(p, "%c %s",
                         (action->flags & SA_INTERRUPT) ? '+' : ' ',
diff --git a/arch/sparc/kernel/sun4d_smp.c b/arch/sparc/kernel/sun4d_smp.c
index 4219dd2ce3a2..41bb9596be48 100644
--- a/arch/sparc/kernel/sun4d_smp.c
+++ b/arch/sparc/kernel/sun4d_smp.c
@@ -249,11 +249,9 @@ void __init smp4d_boot_cpus(void)
         } else {
                 unsigned long bogosum = 0;
                 
-                for(i = 0; i < NR_CPUS; i++) {
-                        if (cpu_isset(i, cpu_present_map)) {
-                                bogosum += cpu_data(i).udelay_val;
-                                smp_highest_cpu = i;
-                        }
+                for_each_present_cpu(i) {
+                        bogosum += cpu_data(i).udelay_val;
+                        smp_highest_cpu = i;
                 }
                 SMP_PRINTK(("Total of %d Processors activated (%lu.%02lu BogoMIPS).\n", cpucount + 1, bogosum/(500000/HZ), (bogosum/(5000/HZ))%100));
                 printk("Total of %d Processors activated (%lu.%02lu BogoMIPS).\n",
diff --git a/arch/sparc/kernel/sun4m_smp.c b/arch/sparc/kernel/sun4m_smp.c
index fbbd8a474c4c..1dde312eebda 100644
--- a/arch/sparc/kernel/sun4m_smp.c
+++ b/arch/sparc/kernel/sun4m_smp.c
@@ -218,10 +218,8 @@ void __init smp4m_boot_cpus(void)
                 cpu_present_map = cpumask_of_cpu(smp_processor_id());
         } else {
                 unsigned long bogosum = 0;
-                for(i = 0; i < NR_CPUS; i++) {
-                        if (cpu_isset(i, cpu_present_map))
-                                bogosum += cpu_data(i).udelay_val;
-                }
+                for_each_present_cpu(i)
+                        bogosum += cpu_data(i).udelay_val;
                 printk("Total of %d Processors activated (%lu.%02lu BogoMIPS).\n",
                        cpucount + 1,
                        bogosum/(500000/HZ),
diff --git a/arch/sparc64/kernel/irq.c b/arch/sparc64/kernel/irq.c
index 8c93ba655b33..e505a4125e35 100644
--- a/arch/sparc64/kernel/irq.c
+++ b/arch/sparc64/kernel/irq.c
@@ -117,9 +117,7 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (j = 0; j < NR_CPUS; j++) {
-                        if (!cpu_online(j))
-                                continue;
+                for_each_online_cpu(j) {
                         seq_printf(p, "%10u ",
                                    kstat_cpu(j).irqs[i]);
                 }
diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index 373a701c90a5..1b6e2ade1008 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -57,25 +57,21 @@ void smp_info(struct seq_file *m)
         int i;
         
         seq_printf(m, "State:\n");
-        for (i = 0; i < NR_CPUS; i++) {
-                if (cpu_online(i))
-                        seq_printf(m,
-                                   "CPU%d:\t\tonline\n", i);
-        }
+        for_each_online_cpu(i)
+                seq_printf(m, "CPU%d:\t\tonline\n", i);
 }
 
 void smp_bogo(struct seq_file *m)
 {
         int i;
         
-        for (i = 0; i < NR_CPUS; i++)
-                if (cpu_online(i))
-                        seq_printf(m,
-                                   "Cpu%dBogo\t: %lu.%02lu\n"
-                                   "Cpu%dClkTck\t: %016lx\n",
-                                   i, cpu_data(i).udelay_val / (500000/HZ),
-                                   (cpu_data(i).udelay_val / (5000/HZ)) % 100,
-                                   i, cpu_data(i).clock_tick);
+        for_each_online_cpu(i)
+                seq_printf(m,
+                           "Cpu%dBogo\t: %lu.%02lu\n"
+                           "Cpu%dClkTck\t: %016lx\n",
+                           i, cpu_data(i).udelay_val / (500000/HZ),
+                           (cpu_data(i).udelay_val / (5000/HZ)) % 100,
+                           i, cpu_data(i).clock_tick);
 }
 
 void __init smp_store_cpu_info(int id)
@@ -1282,7 +1278,7 @@ int setup_profiling_timer(unsigned int multiplier)
                 return -EINVAL;
 
         spin_lock_irqsave(&prof_setup_lock, flags);
-        for (i = 0; i < NR_CPUS; i++)
+        for_each_cpu(i)
                 prof_multiplier(i) = multiplier;
         current_tick_offset = (timer_tick_offset / multiplier);
         spin_unlock_irqrestore(&prof_setup_lock, flags);
@@ -1384,10 +1380,8 @@ void __init smp_cpus_done(unsigned int max_cpus)
         unsigned long bogosum = 0;
         int i;
 
-        for (i = 0; i < NR_CPUS; i++) {
-                if (cpu_online(i))
-                        bogosum += cpu_data(i).udelay_val;
-        }
+        for_each_online_cpu(i)
+                bogosum += cpu_data(i).udelay_val;
         printk("Total of %ld processors activated "
                "(%lu.%02lu BogoMIPS).\n",
                (long) num_online_cpus(),
diff --git a/arch/x86_64/kernel/irq.c b/arch/x86_64/kernel/irq.c
index 30d2a1e545fe..d8bd0b345b1e 100644
--- a/arch/x86_64/kernel/irq.c
+++ b/arch/x86_64/kernel/irq.c
@@ -38,9 +38,8 @@ int show_interrupts(struct seq_file *p, void *v)
 
         if (i == 0) {
                 seq_printf(p, "           ");
-                for (j=0; j<NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "CPU%d       ",j);
+                for_each_online_cpu(j)
+                        seq_printf(p, "CPU%d       ",j);
                 seq_putc(p, '\n');
         }
 
@@ -53,10 +52,8 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (j=0; j<NR_CPUS; j++)
-                        if (cpu_online(j))
-                        seq_printf(p, "%10u ",
-                                kstat_cpu(j).irqs[i]);
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 #endif
                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
 
@@ -68,15 +65,13 @@ skip:
                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
         } else if (i == NR_IRQS) {
                 seq_printf(p, "NMI: ");
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ", cpu_pda(j)->__nmi_count);
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", cpu_pda(j)->__nmi_count);
                 seq_putc(p, '\n');
 #ifdef CONFIG_X86_LOCAL_APIC
                 seq_printf(p, "LOC: ");
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ", cpu_pda(j)->apic_timer_irqs);
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", cpu_pda(j)->apic_timer_irqs);
                 seq_putc(p, '\n');
 #endif
                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 5bf17e41cd2d..66c009e10bac 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -162,9 +162,7 @@ int __init check_nmi_watchdog (void)
         local_irq_enable();
         mdelay((10*1000)/nmi_hz); // wait 10 ticks
 
-        for (cpu = 0; cpu < NR_CPUS; cpu++) {
-                if (!cpu_online(cpu))
-                        continue;
+        for_each_online_cpu(cpu) {
                 if (cpu_pda(cpu)->__nmi_count - counts[cpu] <= 5) {
                         endflag = 1;
                         printk("CPU#%d: NMI appears to be stuck (%d->%d)!\n",
diff --git a/arch/xtensa/kernel/irq.c b/arch/xtensa/kernel/irq.c
index 4cbf6d91571f..51f9bed455fa 100644
--- a/arch/xtensa/kernel/irq.c
+++ b/arch/xtensa/kernel/irq.c
@@ -83,9 +83,8 @@ int show_interrupts(struct seq_file *p, void *v)
 
         if (i == 0) {
                 seq_printf(p, "           ");
-                for (j=0; j<NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "CPU%d       ",j);
+                for_each_online_cpu(j)
+                        seq_printf(p, "CPU%d       ",j);
                 seq_putc(p, '\n');
         }
 
@@ -98,9 +97,8 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
                 seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 #endif
                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
                 seq_printf(p, "  %s", action->name);
@@ -113,9 +111,8 @@ skip:
                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
         } else if (i == NR_IRQS) {
                 seq_printf(p, "NMI: ");
-                for (j = 0; j < NR_CPUS; j++)
-                        if (cpu_online(j))
-                                seq_printf(p, "%10u ", nmi_count(j));
+                for_each_online_cpu(j)
+                        seq_printf(p, "%10u ", nmi_count(j));
                 seq_putc(p, '\n');
                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
         }
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 690a1aae0b34..0c13795dca38 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -172,11 +172,9 @@ static struct net_device_stats *get_stats(struct net_device *dev)
 
         memset(stats, 0, sizeof(struct net_device_stats));
 
-        for (i=0; i < NR_CPUS; i++) {
+        for_each_cpu(i) {
                 struct net_device_stats *lb_stats;
 
-                if (!cpu_possible(i)) 
-                        continue;
                 lb_stats = &per_cpu(loopback_stats, i);
                 stats->rx_bytes   += lb_stats->rx_bytes;
                 stats->tx_bytes   += lb_stats->tx_bytes;
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index 78193e4bbdb5..330d3869b41e 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -38,9 +38,8 @@ void free_cpu_buffers(void)
 {
         int i;
  
-        for_each_online_cpu(i) {
+        for_each_online_cpu(i)
                 vfree(cpu_buffer[i].buffer);
-        }
 }
 
 int alloc_cpu_buffers(void)
diff --git a/fs/xfs/linux-2.6/xfs_stats.c b/fs/xfs/linux-2.6/xfs_stats.c
index 8955720a2c6b..713e6a7505d0 100644
--- a/fs/xfs/linux-2.6/xfs_stats.c
+++ b/fs/xfs/linux-2.6/xfs_stats.c
@@ -62,18 +62,15 @@ xfs_read_xfsstats(
                 while (j < xstats[i].endpoint) {
                         val = 0;
                         /* sum over all cpus */
-                        for (c = 0; c < NR_CPUS; c++) {
-                                if (!cpu_possible(c)) continue;
+                        for_each_cpu(c)
                                 val += *(((__u32*)&per_cpu(xfsstats, c) + j));
-                        }
                         len += sprintf(buffer + len, " %u", val);
                         j++;
                 }
                 buffer[len++] = '\n';
         }
         /* extra precision counters */
-        for (i = 0; i < NR_CPUS; i++) {
-                if (!cpu_possible(i)) continue;
+        for_each_cpu(i) {
                 xs_xstrat_bytes += per_cpu(xfsstats, i).xs_xstrat_bytes;
                 xs_write_bytes += per_cpu(xfsstats, i).xs_write_bytes;
                 xs_read_bytes += per_cpu(xfsstats, i).xs_read_bytes;
diff --git a/fs/xfs/linux-2.6/xfs_sysctl.c b/fs/xfs/linux-2.6/xfs_sysctl.c
index a02564972420..7079cc837210 100644
--- a/fs/xfs/linux-2.6/xfs_sysctl.c
+++ b/fs/xfs/linux-2.6/xfs_sysctl.c
@@ -38,8 +38,7 @@ xfs_stats_clear_proc_handler(
 
         if (!ret && write && *valp) {
                 printk("XFS Clearing xfsstats\n");
-                for (c = 0; c < NR_CPUS; c++) {
-                        if (!cpu_possible(c)) continue;
+                for_each_cpu(c) {
                         preempt_disable();
                         /* save vn_active, it's a universal truth! */
                         vn_active = per_cpu(xfsstats, c).vn_active;
diff --git a/include/asm-alpha/mmu_context.h b/include/asm-alpha/mmu_context.h
index 6f92482cc96c..0c017fc181c1 100644
--- a/include/asm-alpha/mmu_context.h
+++ b/include/asm-alpha/mmu_context.h
@@ -231,9 +231,8 @@ init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 {
         int i;
 
-        for (i = 0; i < NR_CPUS; i++)
-                if (cpu_online(i))
-                        mm->context[i] = 0;
+        for_each_online_cpu(i)
+                mm->context[i] = 0;
         if (tsk != current)
                 task_thread_info(tsk)->pcb.ptbr
                   = ((unsigned long)mm->pgd - IDENT_ADDR) >> PAGE_SHIFT;
diff --git a/include/asm-alpha/topology.h b/include/asm-alpha/topology.h
index eb740e280d9c..420ccde6b916 100644
--- a/include/asm-alpha/topology.h
+++ b/include/asm-alpha/topology.h
@@ -27,8 +27,8 @@ static inline cpumask_t node_to_cpumask(int node)
         cpumask_t node_cpu_mask = CPU_MASK_NONE;
         int cpu;
 
-        for(cpu = 0; cpu < NR_CPUS; cpu++) {
-                if (cpu_online(cpu) && (cpu_to_node(cpu) == node))
+        for_each_online_cpu(cpu) {
+                if (cpu_to_node(cpu) == node)
                         cpu_set(cpu, node_cpu_mask);
         }
 
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 9044aeb37828..78cf45547e31 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -19,10 +19,9 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset[__i], \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset[__i],         \
+                       (src), (size));                          \
 } while (0)
 #else /* ! SMP */
 
diff --git a/include/asm-powerpc/percpu.h b/include/asm-powerpc/percpu.h
index e31922c50e53..464301cd0d03 100644
--- a/include/asm-powerpc/percpu.h
+++ b/include/asm-powerpc/percpu.h
@@ -27,10 +27,9 @@
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset(__i), \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset(__i),         \
+                       (src), (size));                          \
 } while (0)
 
 extern void setup_per_cpu_areas(void);
diff --git a/include/asm-s390/percpu.h b/include/asm-s390/percpu.h
index 123fcaca295e..e10ed87094f0 100644
--- a/include/asm-s390/percpu.h
+++ b/include/asm-s390/percpu.h
@@ -46,10 +46,9 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset[__i], \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset[__i],         \
+                       (src), (size));                          \
 } while (0)
 
 #else /* ! SMP */
diff --git a/include/asm-sparc64/percpu.h b/include/asm-sparc64/percpu.h
index aea4e51e7cd1..82032e159a76 100644
--- a/include/asm-sparc64/percpu.h
+++ b/include/asm-sparc64/percpu.h
@@ -26,10 +26,9 @@ register unsigned long __local_per_cpu_offset asm("g5");
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset(__i), \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset(__i),         \
+                       (src), (size));                          \
 } while (0)
 #else /* ! SMP */
 
diff --git a/include/asm-x86_64/percpu.h b/include/asm-x86_64/percpu.h
index 29a6b0408f75..4405b4adeaba 100644
--- a/include/asm-x86_64/percpu.h
+++ b/include/asm-x86_64/percpu.h
@@ -26,10 +26,9 @@
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset(__i), \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset(__i),         \
+                       (src), (size));                          \
 } while (0)
 
 extern void setup_per_cpu_areas(void);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index eef5ccdcd731..fd647fde5ec1 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -149,22 +149,16 @@ struct disk_attribute {
 ({                                                                      \
         typeof(gendiskp->dkstats->field) res = 0;                       \
         int i;                                                          \
-        for (i=0; i < NR_CPUS; i++) {                                   \
-                if (!cpu_possible(i))                                   \
-                        continue;                                       \
+        for_each_cpu(i)                                                 \
                 res += per_cpu_ptr(gendiskp->dkstats, i)->field;        \
-        }                                                               \
         res;                                                            \
 })
 
 static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)       {
         int i;
-        for (i=0; i < NR_CPUS; i++) {
-                if (cpu_possible(i)) {
-                        memset(per_cpu_ptr(gendiskp->dkstats, i), value,        
-                                        sizeof (struct disk_stats));
-                }
-        }
+        for_each_cpu(i)
+                memset(per_cpu_ptr(gendiskp->dkstats, i), value,
+                                sizeof (struct disk_stats));
 }               
                                 
 #else