generic-ipi: cleanups (0b13fda1) · Commits · e / devices / android_kernel_sony_msm8998

kernel/smp.c

+86 −76

Original line number	Original line	Diff line number	Diff line
	@@ -2,13 +2,12 @@
	* Generic helpers for smp ipi calls		* Generic helpers for smp ipi calls
	*		*
	* (C) Jens Axboe <jens.axboe@oracle.com> 2008		* (C) Jens Axboe <jens.axboe@oracle.com> 2008
	*
	*/		*/
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/percpu.h>
	#include <linux/rcupdate.h>		#include <linux/rcupdate.h>
	#include <linux/rculist.h>		#include <linux/rculist.h>
			#include <linux/module.h>
			#include <linux/percpu.h>
			#include <linux/init.h>
	#include <linux/smp.h>		#include <linux/smp.h>
	#include <linux/cpu.h>		#include <linux/cpu.h>

	@@ -17,7 +16,8 @@ static DEFINE_PER_CPU(struct call_single_queue, call_single_queue);
	static struct {		static struct {
	struct list_head queue;		struct list_head queue;
	spinlock_t lock;		spinlock_t lock;
	} call_function __cacheline_aligned_in_smp = {		} call_function __cacheline_aligned_in_smp =
			{
	.queue = LIST_HEAD_INIT(call_function.queue),		.queue = LIST_HEAD_INIT(call_function.queue),
	.lock = __SPIN_LOCK_UNLOCKED(call_function.lock),		.lock = __SPIN_LOCK_UNLOCKED(call_function.lock),
	};		};
	@@ -96,9 +96,9 @@ early_initcall(init_call_single_data);
	/*		/*
	* csd_lock/csd_unlock used to serialize access to per-cpu csd resources		* csd_lock/csd_unlock used to serialize access to per-cpu csd resources
	*		*
	* For non-synchronous ipi calls the csd can still be in use by the previous		* For non-synchronous ipi calls the csd can still be in use by the
	* function call. For multi-cpu calls its even more interesting as we'll have		* previous function call. For multi-cpu calls its even more interesting
	* to ensure no other cpu is observing our csd.		* as we'll have to ensure no other cpu is observing our csd.
	*/		*/
	static void csd_lock_wait(struct call_single_data *data)		static void csd_lock_wait(struct call_single_data *data)
	{		{
	@@ -112,27 +112,29 @@ static void csd_lock(struct call_single_data *data)
	data->flags = CSD_FLAG_LOCK;		data->flags = CSD_FLAG_LOCK;

	/*		/*
	* prevent CPU from reordering the above assignment to ->flags		* prevent CPU from reordering the above assignment
	* with any subsequent assignments to other fields of the		* to ->flags with any subsequent assignments to other
	* specified call_single_data structure.		* fields of the specified call_single_data structure:
	*/		*/

	smp_mb();		smp_mb();
	}		}

	static void csd_unlock(struct call_single_data *data)		static void csd_unlock(struct call_single_data *data)
	{		{
	WARN_ON(!(data->flags & CSD_FLAG_LOCK));		WARN_ON(!(data->flags & CSD_FLAG_LOCK));

	/*		/*
	* ensure we're all done before releasing data		* ensure we're all done before releasing data:
	*/		*/
	smp_mb();		smp_mb();

	data->flags &= ~CSD_FLAG_LOCK;		data->flags &= ~CSD_FLAG_LOCK;
	}		}

	/*		/*
	* Insert a previously allocated call_single_data element for execution		* Insert a previously allocated call_single_data element
	* on the given CPU. data must already have ->func, ->info, and ->flags set.		* for execution on the given CPU. data must already have
			* ->func, ->info, and ->flags set.
	*/		*/
	static		static
	void generic_exec_single(int cpu, struct call_single_data *data, int wait)		void generic_exec_single(int cpu, struct call_single_data *data, int wait)
	@@ -154,10 +156,9 @@ void generic_exec_single(int cpu, struct call_single_data *data, int wait)
	* If IPIs can go out of order to the cache coherency protocol		* If IPIs can go out of order to the cache coherency protocol
	* in an architecture, sufficient synchronisation should be added		* in an architecture, sufficient synchronisation should be added
	* to arch code to make it appear to obey cache coherency WRT		* to arch code to make it appear to obey cache coherency WRT
	* locking and barrier primitives. Generic code isn't really equipped		* locking and barrier primitives. Generic code isn't really
	* to do the right thing...		* equipped to do the right thing...
	*/		*/

	if (ipi)		if (ipi)
	arch_send_call_function_single_ipi(cpu);		arch_send_call_function_single_ipi(cpu);

	@@ -183,8 +184,8 @@ void generic_smp_call_function_interrupt(void)
	smp_mb();		smp_mb();

	/*		/*
	* It's ok to use list_for_each_rcu() here even though we may delete		* It's ok to use list_for_each_rcu() here even though we may
	* 'pos', since list_del_rcu() doesn't clear ->next		* delete 'pos', since list_del_rcu() doesn't clear ->next
	*/		*/
	list_for_each_entry_rcu(data, &call_function.queue, csd.list) {		list_for_each_entry_rcu(data, &call_function.queue, csd.list) {
	int refs;		int refs;
	@@ -219,14 +220,14 @@ void generic_smp_call_function_interrupt(void)
	}		}

	/*		/*
	* Invoked by arch to handle an IPI for call function single. Must be called		* Invoked by arch to handle an IPI for call function single. Must be
	* from the arch with interrupts disabled.		* called from the arch with interrupts disabled.
	*/		*/
	void generic_smp_call_function_single_interrupt(void)		void generic_smp_call_function_single_interrupt(void)
	{		{
	struct call_single_queue *q = &__get_cpu_var(call_single_queue);		struct call_single_queue *q = &__get_cpu_var(call_single_queue);
	LIST_HEAD(list);
	unsigned int data_flags;		unsigned int data_flags;
			LIST_HEAD(list);

	spin_lock(&q->lock);		spin_lock(&q->lock);
	list_replace_init(&q->list, &list);		list_replace_init(&q->list, &list);
	@@ -235,22 +236,20 @@ void generic_smp_call_function_single_interrupt(void)
	while (!list_empty(&list)) {		while (!list_empty(&list)) {
	struct call_single_data *data;		struct call_single_data *data;

	data = list_entry(list.next, struct call_single_data,		data = list_entry(list.next, struct call_single_data, list);
	list);
	list_del(&data->list);		list_del(&data->list);

	/*		/*
	* 'data' can be invalid after this call if		* 'data' can be invalid after this call if flags == 0
	* flags == 0 (when called through		* (when called through generic_exec_single()),
	* generic_exec_single(), so save them away before		* so save them away before making the call:
	* making the call.
	*/		*/
	data_flags = data->flags;		data_flags = data->flags;

	data->func(data->info);		data->func(data->info);

	/*		/*
	* Unlocked CSDs are valid through generic_exec_single()		* Unlocked CSDs are valid through generic_exec_single():
	*/		*/
	if (data_flags & CSD_FLAG_LOCK)		if (data_flags & CSD_FLAG_LOCK)
	csd_unlock(data);		csd_unlock(data);
	@@ -276,19 +275,24 @@ int smp_call_function_single(int cpu, void (func) (void info), void *info,
	.flags = 0,		.flags = 0,
	};		};
	unsigned long flags;		unsigned long flags;
	/* prevent preemption and reschedule on another processor,		int this_cpu;
	as well as CPU removal */
	int me = get_cpu();
	int err = 0;		int err = 0;

			/*
			* prevent preemption and reschedule on another processor,
			* as well as CPU removal
			*/
			this_cpu = get_cpu();

	/* Can deadlock when called with interrupts disabled */		/* Can deadlock when called with interrupts disabled */
	WARN_ON(irqs_disabled());		WARN_ON(irqs_disabled());

	if (cpu == me) {		if (cpu == this_cpu) {
	local_irq_save(flags);		local_irq_save(flags);
	func(info);		func(info);
	local_irq_restore(flags);		local_irq_restore(flags);
	} else if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {		} else {
			if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {
	struct call_single_data *data = &d;		struct call_single_data *data = &d;

	if (!wait)		if (!wait)
	@@ -302,8 +306,10 @@ int smp_call_function_single(int cpu, void (func) (void info), void *info,
	} else {		} else {
	err = -ENXIO; /* CPU not online */		err = -ENXIO; /* CPU not online */
	}		}
			}

	put_cpu();		put_cpu();

	return err;		return err;
	}		}
	EXPORT_SYMBOL(smp_call_function_single);		EXPORT_SYMBOL(smp_call_function_single);
	@@ -313,10 +319,9 @@ EXPORT_SYMBOL(smp_call_function_single);
	* @cpu: The CPU to run on.		* @cpu: The CPU to run on.
	* @data: Pre-allocated and setup data structure		* @data: Pre-allocated and setup data structure
	*		*
	* Like smp_call_function_single(), but allow caller to pass in a pre-allocated		* Like smp_call_function_single(), but allow caller to pass in a
	* data structure. Useful for embedding @data inside other structures, for		* pre-allocated data structure. Useful for embedding @data inside
	* instance.		* other structures, for instance.
	*
	*/		*/
	void __smp_call_function_single(int cpu, struct call_single_data *data,		void __smp_call_function_single(int cpu, struct call_single_data *data,
	int wait)		int wait)
	@@ -329,7 +334,8 @@ void __smp_call_function_single(int cpu, struct call_single_data *data,
	generic_exec_single(cpu, data, wait);		generic_exec_single(cpu, data, wait);
	}		}

	/* FIXME: Shim for archs using old arch_send_call_function_ipi API. */		/* Deprecated: shim for archs using old arch_send_call_function_ipi API. */

	#ifndef arch_send_call_function_ipi_mask		#ifndef arch_send_call_function_ipi_mask
	# define arch_send_call_function_ipi_mask(maskp) \		# define arch_send_call_function_ipi_mask(maskp) \
	arch_send_call_function_ipi(*(maskp))		arch_send_call_function_ipi(*(maskp))
	@@ -340,7 +346,8 @@ void __smp_call_function_single(int cpu, struct call_single_data *data,
	* @mask: The set of cpus to run on (only runs on online subset).		* @mask: The set of cpus to run on (only runs on online subset).
	* @func: The function to run. This must be fast and non-blocking.		* @func: The function to run. This must be fast and non-blocking.
	* @info: An arbitrary pointer to pass to the function.		* @info: An arbitrary pointer to pass to the function.
	* @wait: If true, wait (atomically) until function has completed on other CPUs.		* @wait: If true, wait (atomically) until function has completed
			* on other CPUs.
	*		*
	* If @wait is true, then returns once @func has returned. Note that @wait		* If @wait is true, then returns once @func has returned. Note that @wait
	* will be implicitly turned on in case of allocation failures, since		* will be implicitly turned on in case of allocation failures, since
	@@ -351,27 +358,27 @@ void __smp_call_function_single(int cpu, struct call_single_data *data,
	* must be disabled when calling this function.		* must be disabled when calling this function.
	*/		*/
	void smp_call_function_many(const struct cpumask *mask,		void smp_call_function_many(const struct cpumask *mask,
	void (func)(void ), void *info,		void (func)(void ), void *info, bool wait)
	bool wait)
	{		{
	struct call_function_data *data;		struct call_function_data *data;
	unsigned long flags;		unsigned long flags;
	int cpu, next_cpu, me = smp_processor_id();		int cpu, next_cpu, this_cpu = smp_processor_id();

	/* Can deadlock when called with interrupts disabled */		/* Can deadlock when called with interrupts disabled */
	WARN_ON(irqs_disabled());		WARN_ON(irqs_disabled());

	/* So, what's a CPU they want? Ignoring this one. */		/* So, what's a CPU they want? Ignoring this one. */
	cpu = cpumask_first_and(mask, cpu_online_mask);		cpu = cpumask_first_and(mask, cpu_online_mask);
	if (cpu == me)		if (cpu == this_cpu)
	cpu = cpumask_next_and(cpu, mask, cpu_online_mask);		cpu = cpumask_next_and(cpu, mask, cpu_online_mask);

	/* No online cpus? We're done. */		/* No online cpus? We're done. */
	if (cpu >= nr_cpu_ids)		if (cpu >= nr_cpu_ids)
	return;		return;

	/* Do we have another CPU which isn't us? */		/* Do we have another CPU which isn't us? */
	next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask);		next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
	if (next_cpu == me)		if (next_cpu == this_cpu)
	next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask);		next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask);

	/* Fastpath: do that cpu by itself. */		/* Fastpath: do that cpu by itself. */
	@@ -387,30 +394,31 @@ void smp_call_function_many(const struct cpumask *mask,
	data->csd.func = func;		data->csd.func = func;
	data->csd.info = info;		data->csd.info = info;
	cpumask_and(data->cpumask, mask, cpu_online_mask);		cpumask_and(data->cpumask, mask, cpu_online_mask);
	cpumask_clear_cpu(me, data->cpumask);		cpumask_clear_cpu(this_cpu, data->cpumask);
	data->refs = cpumask_weight(data->cpumask);		data->refs = cpumask_weight(data->cpumask);

	spin_lock(&call_function.lock);		spin_lock(&call_function.lock);
	/*		/*
	* Place entry at the _HEAD_ of the list, so that any cpu still		* Place entry at the _HEAD_ of the list, so that any cpu still
	* observing the entry in generic_smp_call_function_interrupt() will		* observing the entry in generic_smp_call_function_interrupt()
	* not miss any other list entries.		* will not miss any other list entries:
	*/		*/
	list_add_rcu(&data->csd.list, &call_function.queue);		list_add_rcu(&data->csd.list, &call_function.queue);
	spin_unlock(&call_function.lock);		spin_unlock(&call_function.lock);

	spin_unlock_irqrestore(&data->lock, flags);		spin_unlock_irqrestore(&data->lock, flags);

	/*		/*
	* Make the list addition visible before sending the ipi.		* Make the list addition visible before sending the ipi.
	* (IPIs must obey or appear to obey normal Linux cache coherency		* (IPIs must obey or appear to obey normal Linux cache
	* rules -- see comment in generic_exec_single).		* coherency rules -- see comment in generic_exec_single).
	*/		*/
	smp_mb();		smp_mb();

	/* Send a message to all CPUs in the map */		/* Send a message to all CPUs in the map */
	arch_send_call_function_ipi_mask(data->cpumask);		arch_send_call_function_ipi_mask(data->cpumask);

	/* optionally wait for the CPUs to complete */		/* Optionally wait for the CPUs to complete */
	if (wait)		if (wait)
	csd_lock_wait(&data->csd);		csd_lock_wait(&data->csd);
	}		}
	@@ -420,7 +428,8 @@ EXPORT_SYMBOL(smp_call_function_many);
	* smp_call_function(): Run a function on all other CPUs.		* smp_call_function(): Run a function on all other CPUs.
	* @func: The function to run. This must be fast and non-blocking.		* @func: The function to run. This must be fast and non-blocking.
	* @info: An arbitrary pointer to pass to the function.		* @info: An arbitrary pointer to pass to the function.
	* @wait: If true, wait (atomically) until function has completed on other CPUs.		* @wait: If true, wait (atomically) until function has completed
			* on other CPUs.
	*		*
	* Returns 0.		* Returns 0.
	*		*
	@@ -436,6 +445,7 @@ int smp_call_function(void (func)(void ), void *info, int wait)
	preempt_disable();		preempt_disable();
	smp_call_function_many(cpu_online_mask, func, info, wait);		smp_call_function_many(cpu_online_mask, func, info, wait);
	preempt_enable();		preempt_enable();

	return 0;		return 0;
	}		}
	EXPORT_SYMBOL(smp_call_function);		EXPORT_SYMBOL(smp_call_function);