Fix weird uses of num_online_cpus().

This may be OK in archs with contiguous CPU numbers and without
hotplug CPUs, but it sets a terrible example.

And open-coding it like drivers/scsi/hpsa.c is just weird.

BTRFS has a weird comparison with num_online_cpus() too, but since
BTRFS just screwed up my test machines' root partition, I'm not
touching it :)

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reported-by: Oleg Drokin <green@linuxhacker.ru>
diff --git a/arch/m32r/kernel/smpboot.c b/arch/m32r/kernel/smpboot.c
index bb21f4f..a468467 100644
--- a/arch/m32r/kernel/smpboot.c
+++ b/arch/m32r/kernel/smpboot.c
@@ -376,7 +376,7 @@
 	if (!cpumask_equal(&cpu_callin_map, cpu_online_mask))
 		BUG();
 
-	for (cpu_id = 0 ; cpu_id < num_online_cpus() ; cpu_id++)
+	for_each_online_cpu(cpu_id)
 		show_cpu_info(cpu_id);
 
 	/*
diff --git a/arch/sh/include/asm/mmu_context.h b/arch/sh/include/asm/mmu_context.h
index b9d9489..9f417fe 100644
--- a/arch/sh/include/asm/mmu_context.h
+++ b/arch/sh/include/asm/mmu_context.h
@@ -99,7 +99,7 @@
 {
 	int i;
 
-	for (i = 0; i < num_online_cpus(); i++)
+	for_each_online_cpu(i)
 		cpu_context(i, mm) = NO_CONTEXT;
 
 	return 0;
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index fc5acfc..de6be00 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -363,7 +363,7 @@
 		smp_call_function(flush_tlb_mm_ipi, (void *)mm, 1);
 	} else {
 		int i;
-		for (i = 0; i < num_online_cpus(); i++)
+		for_each_online_cpu(i)
 			if (smp_processor_id() != i)
 				cpu_context(i, mm) = 0;
 	}
@@ -400,7 +400,7 @@
 		smp_call_function(flush_tlb_range_ipi, (void *)&fd, 1);
 	} else {
 		int i;
-		for (i = 0; i < num_online_cpus(); i++)
+		for_each_online_cpu(i)
 			if (smp_processor_id() != i)
 				cpu_context(i, mm) = 0;
 	}
@@ -443,7 +443,7 @@
 		smp_call_function(flush_tlb_page_ipi, (void *)&fd, 1);
 	} else {
 		int i;
-		for (i = 0; i < num_online_cpus(); i++)
+		for_each_online_cpu(i)
 			if (smp_processor_id() != i)
 				cpu_context(i, vma->vm_mm) = 0;
 	}
diff --git a/arch/um/kernel/smp.c b/arch/um/kernel/smp.c
index 7407789..525c365 100644
--- a/arch/um/kernel/smp.c
+++ b/arch/um/kernel/smp.c
@@ -45,7 +45,7 @@
 	int i;
 
 	printk(KERN_INFO "Stopping all CPUs...");
-	for (i = 0; i < num_online_cpus(); i++) {
+	for_each_online_cpu(i) {
 		if (i == current_thread->cpu)
 			continue;
 		os_write_file(cpu_data[i].ipi_pipe[1], "S", 1);
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index a1cfbd3..8eab107 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -6632,14 +6632,12 @@
 
 static void set_lockup_detected_for_all_cpus(struct ctlr_info *h, u32 value)
 {
-	int i, cpu;
+	int cpu;
 
-	cpu = cpumask_first(cpu_online_mask);
-	for (i = 0; i < num_online_cpus(); i++) {
+	for_each_online_cpu(cpu) {
 		u32 *lockup_detected;
 		lockup_detected = per_cpu_ptr(h->lockup_detected, cpu);
 		*lockup_detected = value;
-		cpu = cpumask_next(cpu, cpu_online_mask);
 	}
 	wmb(); /* be sure the per-cpu variables are out to memory */
 }