[IA64] Add hotplug cpu to salinfo.c, replace semaphore with mutex (e026cca0) · Commits · e / devices / android_kernel_oneplus_sm7250

arch/ia64/kernel/salinfo.c

+119 −51

Original line number	Diff line number	Diff line
		@@ -3,7 +3,7 @@
		*
		* Creates entries in /proc/sal for various system features.
		*
		* Copyright (c) 2003 Silicon Graphics, Inc. All rights reserved.
		* Copyright (c) 2003, 2006 Silicon Graphics, Inc. All rights reserved.
		* Copyright (c) 2003 Hewlett-Packard Co
		* Bjorn Helgaas <bjorn.helgaas@hp.com>
		*
		@@ -27,9 +27,17 @@
		* mca.c may not pass a buffer, a NULL buffer just indicates that a new
		* record is available in SAL.
		* Replace some NR_CPUS by cpus_online, for hotplug cpu.
		*
		* Jan 5 2006 kaos@sgi.com
		* Handle hotplug cpus coming online.
		* Handle hotplug cpus going offline while they still have outstanding records.
		* Use the cpu_* macros consistently.
		* Replace the counting semaphore with a mutex and a test if the cpumask is non-empty.
		* Modify the locking to make the test for "work to do" an atomic operation.
		*/

		#include <linux/capability.h>
		#include <linux/cpu.h>
		#include <linux/types.h>
		#include <linux/proc_fs.h>
		#include <linux/module.h>
		@@ -132,8 +140,8 @@ enum salinfo_state {
		};

		struct salinfo_data {
		volatile cpumask_t cpu_event; /* which cpus have outstanding events */
		struct semaphore sem; /* count of cpus with outstanding events (bits set in cpu_event) */
		cpumask_t cpu_event; /* which cpus have outstanding events */
		struct semaphore mutex;
		u8 *log_buffer;
		u64 log_size;
		u8 oemdata; / decoded oem data */
		@@ -174,6 +182,21 @@ struct salinfo_platform_oemdata_parms {
		int ret;
		};

		/* Kick the mutex that tells user space that there is work to do. Instead of
		* trying to track the state of the mutex across multiple cpus, in user
		* context, interrupt context, non-maskable interrupt context and hotplug cpu,
		* it is far easier just to grab the mutex if it is free then release it.
		*
		* This routine must be called with data_saved_lock held, to make the down/up
		* operation atomic.
		*/
		static void
		salinfo_work_to_do(struct salinfo_data *data)
		{
		down_trylock(&data->mutex);
		up(&data->mutex);
		}

		static void
		salinfo_platform_oemdata_cpu(void *context)
		{
		@@ -212,9 +235,9 @@ salinfo_log_wakeup(int type, u8 *buffer, u64 size, int irqsafe)

		BUG_ON(type >= ARRAY_SIZE(salinfo_log_name));

		if (buffer) {
		if (irqsafe)
		spin_lock_irqsave(&data_saved_lock, flags);
		if (buffer) {
		for (i = 0, data_saved = data->data_saved; i < saved_size; ++i, ++data_saved) {
		if (!data_saved->buffer)
		break;
		@@ -232,13 +255,11 @@ salinfo_log_wakeup(int type, u8 *buffer, u64 size, int irqsafe)
		data_saved->size = size;
		data_saved->buffer = buffer;
		}
		if (irqsafe)
		spin_unlock_irqrestore(&data_saved_lock, flags);
		}

		if (!test_and_set_bit(smp_processor_id(), &data->cpu_event)) {
		if (irqsafe)
		up(&data->sem);
		cpu_set(smp_processor_id(), data->cpu_event);
		if (irqsafe) {
		salinfo_work_to_do(data);
		spin_unlock_irqrestore(&data_saved_lock, flags);
		}
		}

		@@ -249,16 +270,13 @@ static struct timer_list salinfo_timer;
		static void
		salinfo_timeout_check(struct salinfo_data *data)
		{
		int i;
		unsigned long flags;
		if (!data->open)
		return;
		for_each_online_cpu(i) {
		if (test_bit(i, &data->cpu_event)) {
		/* double up() is not a problem, user space will see no
		* records for the additional "events".
		*/
		up(&data->sem);
		}
		if (!cpus_empty(data->cpu_event)) {
		spin_lock_irqsave(&data_saved_lock, flags);
		salinfo_work_to_do(data);
		spin_unlock_irqrestore(&data_saved_lock, flags);
		}
		}

		@@ -290,16 +308,20 @@ salinfo_event_read(struct file file, char __user buffer, size_t count, loff_t
		int i, n, cpu = -1;

		retry:
		if (down_trylock(&data->sem)) {
		if (cpus_empty(data->cpu_event) && down_trylock(&data->mutex)) {
		if (file->f_flags & O_NONBLOCK)
		return -EAGAIN;
		if (down_interruptible(&data->sem))
		if (down_interruptible(&data->mutex))
		return -EINTR;
		}

		n = data->cpu_check;
		for (i = 0; i < NR_CPUS; i++) {
		if (test_bit(n, &data->cpu_event) && cpu_online(n)) {
		if (cpu_isset(n, data->cpu_event)) {
		if (!cpu_online(n)) {
		cpu_clear(n, data->cpu_event);
		continue;
		}
		cpu = n;
		break;
		}
		@@ -310,9 +332,6 @@ salinfo_event_read(struct file file, char __user buffer, size_t count, loff_t
		if (cpu == -1)
		goto retry;

		/* events are sticky until the user says "clear" */
		up(&data->sem);

		/* for next read, start checking at next CPU */
		data->cpu_check = cpu;
		if (++data->cpu_check == NR_CPUS)
		@@ -381,10 +400,8 @@ salinfo_log_release(struct inode inode, struct file file)
		static void
		call_on_cpu(int cpu, void (fn)(void ), void *arg)
		{
		cpumask_t save_cpus_allowed, new_cpus_allowed;
		memcpy(&save_cpus_allowed, &current->cpus_allowed, sizeof(save_cpus_allowed));
		memset(&new_cpus_allowed, 0, sizeof(new_cpus_allowed));
		set_bit(cpu, &new_cpus_allowed);
		cpumask_t save_cpus_allowed = current->cpus_allowed;
		cpumask_t new_cpus_allowed = cpumask_of_cpu(cpu);
		set_cpus_allowed(current, new_cpus_allowed);
		(*fn)(arg);
		set_cpus_allowed(current, save_cpus_allowed);
		@@ -434,7 +451,7 @@ salinfo_log_new_read(int cpu, struct salinfo_data *data)
		call_on_cpu(cpu, salinfo_log_read_cpu, data);
		if (!data->log_size) {
		data->state = STATE_NO_DATA;
		clear_bit(cpu, &data->cpu_event);
		cpu_clear(cpu, data->cpu_event);
		} else {
		data->state = STATE_LOG_RECORD;
		}
		@@ -473,27 +490,31 @@ static int
		salinfo_log_clear(struct salinfo_data *data, int cpu)
		{
		sal_log_record_header_t *rh;
		unsigned long flags;
		spin_lock_irqsave(&data_saved_lock, flags);
		data->state = STATE_NO_DATA;
		if (!test_bit(cpu, &data->cpu_event))
		if (!cpu_isset(cpu, data->cpu_event)) {
		spin_unlock_irqrestore(&data_saved_lock, flags);
		return 0;
		down(&data->sem);
		clear_bit(cpu, &data->cpu_event);
		}
		cpu_clear(cpu, data->cpu_event);
		if (data->saved_num) {
		unsigned long flags;
		spin_lock_irqsave(&data_saved_lock, flags);
		shift1_data_saved(data, data->saved_num - 1);
		data->saved_num = 0;
		spin_unlock_irqrestore(&data_saved_lock, flags);
		}
		spin_unlock_irqrestore(&data_saved_lock, flags);
		rh = (sal_log_record_header_t *)(data->log_buffer);
		/* Corrected errors have already been cleared from SAL */
		if (rh->severity != sal_log_severity_corrected)
		call_on_cpu(cpu, salinfo_log_clear_cpu, data);
		/* clearing a record may make a new record visible */
		salinfo_log_new_read(cpu, data);
		if (data->state == STATE_LOG_RECORD &&
		!test_and_set_bit(cpu, &data->cpu_event))
		up(&data->sem);
		if (data->state == STATE_LOG_RECORD) {
		spin_lock_irqsave(&data_saved_lock, flags);
		cpu_set(cpu, data->cpu_event);
		salinfo_work_to_do(data);
		spin_unlock_irqrestore(&data_saved_lock, flags);
		}
		return 0;
		}

		@@ -550,6 +571,53 @@ static struct file_operations salinfo_data_fops = {
		.write = salinfo_log_write,
		};

		#ifdef CONFIG_HOTPLUG_CPU
		static int __devinit
		salinfo_cpu_callback(struct notifier_block nb, unsigned long action, void hcpu)
		{
		unsigned int i, cpu = (unsigned long)hcpu;
		unsigned long flags;
		struct salinfo_data *data;
		switch (action) {
		case CPU_ONLINE:
		spin_lock_irqsave(&data_saved_lock, flags);
		for (i = 0, data = salinfo_data;
		i < ARRAY_SIZE(salinfo_data);
		++i, ++data) {
		cpu_set(cpu, data->cpu_event);
		salinfo_work_to_do(data);
		}
		spin_unlock_irqrestore(&data_saved_lock, flags);
		break;
		case CPU_DEAD:
		spin_lock_irqsave(&data_saved_lock, flags);
		for (i = 0, data = salinfo_data;
		i < ARRAY_SIZE(salinfo_data);
		++i, ++data) {
		struct salinfo_data_saved *data_saved;
		int j;
		for (j = ARRAY_SIZE(data->data_saved) - 1, data_saved = data->data_saved + j;
		j >= 0;
		--j, --data_saved) {
		if (data_saved->buffer && data_saved->cpu == cpu) {
		shift1_data_saved(data, j);
		}
		}
		cpu_clear(cpu, data->cpu_event);
		}
		spin_unlock_irqrestore(&data_saved_lock, flags);
		break;
		}
		return NOTIFY_OK;
		}

		static struct notifier_block salinfo_cpu_notifier =
		{
		.notifier_call = salinfo_cpu_callback,
		.priority = 0,
		};
		#endif /* CONFIG_HOTPLUG_CPU */

		static int __init
		salinfo_init(void)
		{
		@@ -557,7 +625,7 @@ salinfo_init(void)
		struct proc_dir_entry *sdir = salinfo_proc_entries; / keeps track of every entry */
		struct proc_dir_entry dir, entry;
		struct salinfo_data *data;
		int i, j, online;
		int i, j;

		salinfo_dir = proc_mkdir("sal", NULL);
		if (!salinfo_dir)
		@@ -572,7 +640,7 @@ salinfo_init(void)
		for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) {
		data = salinfo_data + i;
		data->type = i;
		sema_init(&data->sem, 0);
		init_MUTEX(&data->mutex);
		dir = proc_mkdir(salinfo_log_name[i], salinfo_dir);
		if (!dir)
		continue;
		@@ -592,12 +660,8 @@ salinfo_init(void)
		*sdir++ = entry;

		/* we missed any events before now */
		online = 0;
		for_each_online_cpu(j) {
		set_bit(j, &data->cpu_event);
		++online;
		}
		sema_init(&data->sem, online);
		for_each_online_cpu(j)
		cpu_set(j, data->cpu_event);

		*sdir++ = dir;
		}
		@@ -609,6 +673,10 @@ salinfo_init(void)
		salinfo_timer.function = &salinfo_timeout;
		add_timer(&salinfo_timer);

		#ifdef CONFIG_HOTPLUG_CPU
		register_cpu_notifier(&salinfo_cpu_notifier);
		#endif

		return 0;
		}