[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>

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);

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;

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++;
 	}

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;
 }

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;
 
 	/*

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;

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);

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);

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 */

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;

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:

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

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 */

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) {

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) {

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) {

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);

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');
 	}
 

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;
 }

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');
 	}