Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-f…

…or-linus

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  stop_machine: fix up ftrace.c
  stop_machine: Wean existing callers off stop_machine_run()
  stop_machine(): stop_machine_run() changed to use cpu mask
  Hotplug CPU: don't check cpu_online after take_cpu_down
  Simplify stop_machine
  stop_machine: add ALL_CPUS option
  module: fix build warning with !CONFIG_KALLSYMS

arch/s390/kernel/kprobes.c

@@ -197,7 +197,7 @@ void __kprobes arch_arm_kprobe(struct kprobe *p)
 	args.new = BREAKPOINT_INSTRUCTION;
 
 	kcb->kprobe_status = KPROBE_SWAP_INST;
-	stop_machine_run(swap_instruction, &args, NR_CPUS);
+	stop_machine(swap_instruction, &args, NULL);
 	kcb->kprobe_status = status;
 }
 
@@ -212,7 +212,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 	args.new = p->opcode;
 
 	kcb->kprobe_status = KPROBE_SWAP_INST;
-	stop_machine_run(swap_instruction, &args, NR_CPUS);
+	stop_machine(swap_instruction, &args, NULL);
 	kcb->kprobe_status = status;
 }
 
@@ -331,7 +331,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 		 * No kprobe at this address. The fault has not been
 		 * caused by a kprobe breakpoint. The race of breakpoint
 		 * vs. kprobe remove does not exist because on s390 we
-		 * use stop_machine_run to arm/disarm the breakpoints.
+		 * use stop_machine to arm/disarm the breakpoints.
 		 */
 		goto no_kprobe;
 

drivers/char/hw_random/intel-rng.c

@@ -241,7 +241,7 @@ static int __init intel_rng_hw_init(void *_intel_rng_hw)
 	struct intel_rng_hw *intel_rng_hw = _intel_rng_hw;
 	u8 mfc, dvc;
 
-	/* interrupts disabled in stop_machine_run call */
+	/* interrupts disabled in stop_machine call */
 
 	if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK))
 		pci_write_config_byte(intel_rng_hw->dev,
@@ -365,10 +365,10 @@ static int __init mod_init(void)
 	 * location with the Read ID command, all activity on the system
 	 * must be stopped until the state is back to normal.
 	 *
-	 * Use stop_machine_run because IPIs can be blocked by disabling
+	 * Use stop_machine because IPIs can be blocked by disabling
 	 * interrupts.
 	 */
-	err = stop_machine_run(intel_rng_hw_init, intel_rng_hw, NR_CPUS);
+	err = stop_machine(intel_rng_hw_init, intel_rng_hw, NULL);
 	pci_dev_put(dev);
 	iounmap(intel_rng_hw->mem);
 	kfree(intel_rng_hw);

include/linux/stop_machine.h

@@ -5,41 +5,43 @@
    (and more).  So the "read" side to such a lock is anything which
    diables preeempt. */
 #include <linux/cpu.h>
+#include <linux/cpumask.h>
 #include <asm/system.h>
 
 #if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
+
+/* Deprecated, but useful for transition. */
+#define ALL_CPUS ~0U
+
 /**
- * stop_machine_run: freeze the machine on all CPUs and run this function
+ * stop_machine: freeze the machine on all CPUs and run this function
  * @fn: the function to run
  * @data: the data ptr for the @fn()
- * @cpu: the cpu to run @fn() on (or any, if @cpu == NR_CPUS.
+ * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
  *
- * Description: This causes a thread to be scheduled on every other cpu,
- * each of which disables interrupts, and finally interrupts are disabled
- * on the current CPU.  The result is that noone is holding a spinlock
- * or inside any other preempt-disabled region when @fn() runs.
+ * Description: This causes a thread to be scheduled on every cpu,
+ * each of which disables interrupts.  The result is that noone is
+ * holding a spinlock or inside any other preempt-disabled region when
+ * @fn() runs.
  *
  * This can be thought of as a very heavy write lock, equivalent to
  * grabbing every spinlock in the kernel. */
-int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu);
+int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus);
 
 /**
- * __stop_machine_run: freeze the machine on all CPUs and run this function
+ * __stop_machine: freeze the machine on all CPUs and run this function
  * @fn: the function to run
  * @data: the data ptr for the @fn
- * @cpu: the cpu to run @fn on (or any, if @cpu == NR_CPUS.
+ * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
  *
- * Description: This is a special version of the above, which returns the
- * thread which has run @fn(): kthread_stop will return the return value
- * of @fn().  Used by hotplug cpu.
+ * Description: This is a special version of the above, which assumes cpus
+ * won't come or go while it's being called.  Used by hotplug cpu.
  */
-struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
-				       unsigned int cpu);
-
+int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus);
 #else
 
-static inline int stop_machine_run(int (*fn)(void *), void *data,
-				   unsigned int cpu)
+static inline int stop_machine(int (*fn)(void *), void *data,
+			       const cpumask_t *cpus)
 {
 	int ret;
 	local_irq_disable();
@@ -48,4 +50,18 @@ static inline int stop_machine_run(int (*fn)(void *), void *data,
 	return ret;
 }
 #endif /* CONFIG_SMP */
+
+static inline int __deprecated stop_machine_run(int (*fn)(void *), void *data,
+						unsigned int cpu)
+{
+	/* If they don't care which cpu fn runs on, just pick one. */
+	if (cpu == NR_CPUS)
+		return stop_machine(fn, data, NULL);
+	else if (cpu == ~0U)
+		return stop_machine(fn, data, &cpu_possible_map);
+	else {
+		cpumask_t cpus = cpumask_of_cpu(cpu);
+		return stop_machine(fn, data, &cpus);
+	}
+}
 #endif /* _LINUX_STOP_MACHINE */

kernel/cpu.c

@@ -216,7 +216,6 @@ static int __ref take_cpu_down(void *_param)
 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 {
 	int err, nr_calls = 0;
-	struct task_struct *p;
 	cpumask_t old_allowed, tmp;
 	void *hcpu = (void *)(long)cpu;
 	unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
@@ -249,21 +248,18 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 	cpus_setall(tmp);
 	cpu_clear(cpu, tmp);
 	set_cpus_allowed_ptr(current, &tmp);
+	tmp = cpumask_of_cpu(cpu);
 
-	p = __stop_machine_run(take_cpu_down, &tcd_param, cpu);
-
-	if (IS_ERR(p) || cpu_online(cpu)) {
+	err = __stop_machine(take_cpu_down, &tcd_param, &tmp);
+	if (err) {
 		/* CPU didn't die: tell everyone.  Can't complain. */
 		if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
 					    hcpu) == NOTIFY_BAD)
 			BUG();
 
-		if (IS_ERR(p)) {
-			err = PTR_ERR(p);
-			goto out_allowed;
-		}
-		goto out_thread;
+		goto out_allowed;
 	}
+	BUG_ON(cpu_online(cpu));
 
 	/* Wait for it to sleep (leaving idle task). */
 	while (!idle_cpu(cpu))
@@ -279,8 +275,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 
 	check_for_tasks(cpu);
 
-out_thread:
-	err = kthread_stop(p);
 out_allowed:
 	set_cpus_allowed_ptr(current, &old_allowed);
 out_release:

kernel/module.c

@@ -325,18 +325,6 @@ static unsigned long find_symbol(const char *name,
 	return -ENOENT;
 }
 
-/* lookup symbol in given range of kernel_symbols */
-static const struct kernel_symbol *lookup_symbol(const char *name,
-	const struct kernel_symbol *start,
-	const struct kernel_symbol *stop)
-{
-	const struct kernel_symbol *ks = start;
-	for (; ks < stop; ks++)
-		if (strcmp(ks->name, name) == 0)
-			return ks;
-	return NULL;
-}
-
 /* Search for module by name: must hold module_mutex. */
 static struct module *find_module(const char *name)
 {
@@ -690,7 +678,7 @@ static int try_stop_module(struct module *mod, int flags, int *forced)
 	if (flags & O_NONBLOCK) {
 		struct stopref sref = { mod, flags, forced };
 
-		return stop_machine_run(__try_stop_module, &sref, NR_CPUS);
+		return stop_machine(__try_stop_module, &sref, NULL);
 	} else {
 		/* We don't need to stop the machine for this. */
 		mod->state = MODULE_STATE_GOING;
@@ -1428,7 +1416,7 @@ static int __unlink_module(void *_mod)
 static void free_module(struct module *mod)
 {
 	/* Delete from various lists */
-	stop_machine_run(__unlink_module, mod, NR_CPUS);
+	stop_machine(__unlink_module, mod, NULL);
 	remove_notes_attrs(mod);
 	remove_sect_attrs(mod);
 	mod_kobject_remove(mod);
@@ -1703,6 +1691,19 @@ static void setup_modinfo(struct module *mod, Elf_Shdr *sechdrs,
 }
 
 #ifdef CONFIG_KALLSYMS
+
+/* lookup symbol in given range of kernel_symbols */
+static const struct kernel_symbol *lookup_symbol(const char *name,
+	const struct kernel_symbol *start,
+	const struct kernel_symbol *stop)
+{
+	const struct kernel_symbol *ks = start;
+	for (; ks < stop; ks++)
+		if (strcmp(ks->name, name) == 0)
+			return ks;
+	return NULL;
+}
+
 static int is_exported(const char *name, const struct module *mod)
 {
 	if (!mod && lookup_symbol(name, __start___ksymtab, __stop___ksymtab))
@@ -2196,7 +2197,7 @@ static struct module *load_module(void __user *umod,
 	/* Now sew it into the lists so we can get lockdep and oops
          * info during argument parsing.  Noone should access us, since
          * strong_try_module_get() will fail. */
-	stop_machine_run(__link_module, mod, NR_CPUS);
+	stop_machine(__link_module, mod, NULL);
 
 	/* Size of section 0 is 0, so this works well if no params */
 	err = parse_args(mod->name, mod->args,
@@ -2230,7 +2231,7 @@ static struct module *load_module(void __user *umod,
 	return mod;
 
  unlink:
-	stop_machine_run(__unlink_module, mod, NR_CPUS);
+	stop_machine(__unlink_module, mod, NULL);
 	module_arch_cleanup(mod);
  cleanup:
 	kobject_del(&mod->mkobj.kobj);

kernel/rcuclassic.c

@@ -91,8 +91,8 @@ static void force_quiescent_state(struct rcu_data *rdp,
 		 * rdp->cpu is the current cpu.
 		 *
 		 * cpu_online_map is updated by the _cpu_down()
-		 * using stop_machine_run(). Since we're in irqs disabled
-		 * section, stop_machine_run() is not exectuting, hence
+		 * using __stop_machine(). Since we're in irqs disabled
+		 * section, __stop_machine() is not exectuting, hence
 		 * the cpu_online_map is stable.
 		 *
 		 * However,  a cpu might have been offlined _just_ before