blob: c3fec1413295bb142305d501fd83f694204c8f00 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* padata.c - generic interface to process data streams in parallel
*
* See Documentation/padata.txt for an api documentation.
*
* Copyright (C) 2008, 2009 secunet Security Networks AG
* Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <linux/export.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/cpu.h>
#include <linux/padata.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/rcupdate.h>
#include <linux/module.h>
#define MAX_OBJ_NUM 1000
static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
{
int cpu, target_cpu;
target_cpu = cpumask_first(pd->cpumask.pcpu);
for (cpu = 0; cpu < cpu_index; cpu++)
target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
return target_cpu;
}
static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr)
{
/*
* Hash the sequence numbers to the cpus by taking
* seq_nr mod. number of cpus in use.
*/
int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
return padata_index_to_cpu(pd, cpu_index);
}
static void padata_parallel_worker(struct work_struct *parallel_work)
{
struct padata_parallel_queue *pqueue;
LIST_HEAD(local_list);
local_bh_disable();
pqueue = container_of(parallel_work,
struct padata_parallel_queue, work);
spin_lock(&pqueue->parallel.lock);
list_replace_init(&pqueue->parallel.list, &local_list);
spin_unlock(&pqueue->parallel.lock);
while (!list_empty(&local_list)) {
struct padata_priv *padata;
padata = list_entry(local_list.next,
struct padata_priv, list);
list_del_init(&padata->list);
padata->parallel(padata);
}
local_bh_enable();
}
/**
* padata_do_parallel - padata parallelization function
*
* @pinst: padata instance
* @padata: object to be parallelized
* @cb_cpu: pointer to the CPU that the serialization callback function should
* run on. If it's not in the serial cpumask of @pinst
* (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
* none found, returns -EINVAL.
*
* The parallelization callback function will run with BHs off.
* Note: Every object which is parallelized by padata_do_parallel
* must be seen by padata_do_serial.
*/
int padata_do_parallel(struct padata_instance *pinst,
struct padata_priv *padata, int *cb_cpu)
{
int i, cpu, cpu_index, target_cpu, err;
struct padata_parallel_queue *queue;
struct parallel_data *pd;
rcu_read_lock_bh();
pd = rcu_dereference_bh(pinst->pd);
err = -EINVAL;
if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
goto out;
if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) {
if (!cpumask_weight(pd->cpumask.cbcpu))
goto out;
/* Select an alternate fallback CPU and notify the caller. */
cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
cpu = cpumask_first(pd->cpumask.cbcpu);
for (i = 0; i < cpu_index; i++)
cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
*cb_cpu = cpu;
}
err = -EBUSY;
if ((pinst->flags & PADATA_RESET))
goto out;
if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
goto out;
err = 0;
atomic_inc(&pd->refcnt);
padata->pd = pd;
padata->cb_cpu = *cb_cpu;
padata->seq_nr = atomic_inc_return(&pd->seq_nr);
target_cpu = padata_cpu_hash(pd, padata->seq_nr);
padata->cpu = target_cpu;
queue = per_cpu_ptr(pd->pqueue, target_cpu);
spin_lock(&queue->parallel.lock);
list_add_tail(&padata->list, &queue->parallel.list);
spin_unlock(&queue->parallel.lock);
queue_work(pinst->parallel_wq, &queue->work);
out:
rcu_read_unlock_bh();
return err;
}
EXPORT_SYMBOL(padata_do_parallel);
/*
* padata_find_next - Find the next object that needs serialization.
*
* Return values are:
*
* A pointer to the control struct of the next object that needs
* serialization, if present in one of the percpu reorder queues.
*
* NULL, if the next object that needs serialization will
* be parallel processed by another cpu and is not yet present in
* the cpu's reorder queue.
*/
static struct padata_priv *padata_find_next(struct parallel_data *pd,
bool remove_object)
{
struct padata_parallel_queue *next_queue;
struct padata_priv *padata;
struct padata_list *reorder;
int cpu = pd->cpu;
next_queue = per_cpu_ptr(pd->pqueue, cpu);
reorder = &next_queue->reorder;
spin_lock(&reorder->lock);
if (list_empty(&reorder->list)) {
spin_unlock(&reorder->lock);
return NULL;
}
padata = list_entry(reorder->list.next, struct padata_priv, list);
/*
* Checks the rare case where two or more parallel jobs have hashed to
* the same CPU and one of the later ones finishes first.
*/
if (padata->seq_nr != pd->processed) {
spin_unlock(&reorder->lock);
return NULL;
}
if (remove_object) {
list_del_init(&padata->list);
atomic_dec(&pd->reorder_objects);
++pd->processed;
pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false);
}
spin_unlock(&reorder->lock);
return padata;
}
static void padata_reorder(struct parallel_data *pd)
{
int cb_cpu;
struct padata_priv *padata;
struct padata_serial_queue *squeue;
struct padata_instance *pinst = pd->pinst;
struct padata_parallel_queue *next_queue;
/*
* We need to ensure that only one cpu can work on dequeueing of
* the reorder queue the time. Calculating in which percpu reorder
* queue the next object will arrive takes some time. A spinlock
* would be highly contended. Also it is not clear in which order
* the objects arrive to the reorder queues. So a cpu could wait to
* get the lock just to notice that there is nothing to do at the
* moment. Therefore we use a trylock and let the holder of the lock
* care for all the objects enqueued during the holdtime of the lock.
*/
if (!spin_trylock_bh(&pd->lock))
return;
while (1) {
padata = padata_find_next(pd, true);
/*
* If the next object that needs serialization is parallel
* processed by another cpu and is still on it's way to the
* cpu's reorder queue, nothing to do for now.
*/
if (!padata)
break;
cb_cpu = padata->cb_cpu;
squeue = per_cpu_ptr(pd->squeue, cb_cpu);
spin_lock(&squeue->serial.lock);
list_add_tail(&padata->list, &squeue->serial.list);
spin_unlock(&squeue->serial.lock);
queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work);
}
spin_unlock_bh(&pd->lock);
/*
* The next object that needs serialization might have arrived to
* the reorder queues in the meantime.
*
* Ensure reorder queue is read after pd->lock is dropped so we see
* new objects from another task in padata_do_serial. Pairs with
* smp_mb__after_atomic in padata_do_serial.
*/
smp_mb();
next_queue = per_cpu_ptr(pd->pqueue, pd->cpu);
if (!list_empty(&next_queue->reorder.list) &&
padata_find_next(pd, false))
queue_work(pinst->serial_wq, &pd->reorder_work);
}
static void invoke_padata_reorder(struct work_struct *work)
{
struct parallel_data *pd;
local_bh_disable();
pd = container_of(work, struct parallel_data, reorder_work);
padata_reorder(pd);
local_bh_enable();
}
static void padata_serial_worker(struct work_struct *serial_work)
{
struct padata_serial_queue *squeue;
struct parallel_data *pd;
LIST_HEAD(local_list);
local_bh_disable();
squeue = container_of(serial_work, struct padata_serial_queue, work);
pd = squeue->pd;
spin_lock(&squeue->serial.lock);
list_replace_init(&squeue->serial.list, &local_list);
spin_unlock(&squeue->serial.lock);
while (!list_empty(&local_list)) {
struct padata_priv *padata;
padata = list_entry(local_list.next,
struct padata_priv, list);
list_del_init(&padata->list);
padata->serial(padata);
atomic_dec(&pd->refcnt);
}
local_bh_enable();
}
/**
* padata_do_serial - padata serialization function
*
* @padata: object to be serialized.
*
* padata_do_serial must be called for every parallelized object.
* The serialization callback function will run with BHs off.
*/
void padata_do_serial(struct padata_priv *padata)
{
struct parallel_data *pd = padata->pd;
struct padata_parallel_queue *pqueue = per_cpu_ptr(pd->pqueue,
padata->cpu);
struct padata_priv *cur;
spin_lock(&pqueue->reorder.lock);
/* Sort in ascending order of sequence number. */
list_for_each_entry_reverse(cur, &pqueue->reorder.list, list)
if (cur->seq_nr < padata->seq_nr)
break;
list_add(&padata->list, &cur->list);
atomic_inc(&pd->reorder_objects);
spin_unlock(&pqueue->reorder.lock);
/*
* Ensure the addition to the reorder list is ordered correctly
* with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
* in padata_reorder.
*/
smp_mb__after_atomic();
padata_reorder(pd);
}
EXPORT_SYMBOL(padata_do_serial);
static int padata_setup_cpumasks(struct parallel_data *pd,
const struct cpumask *pcpumask,
const struct cpumask *cbcpumask)
{
struct workqueue_attrs *attrs;
int err = -ENOMEM;
if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
goto out;
cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL))
goto free_pcpu_mask;
cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
attrs = alloc_workqueue_attrs();
if (!attrs)
goto free_cbcpu_mask;
/* Restrict parallel_wq workers to pd->cpumask.pcpu. */
cpumask_copy(attrs->cpumask, pd->cpumask.pcpu);
err = apply_workqueue_attrs(pd->pinst->parallel_wq, attrs);
free_workqueue_attrs(attrs);
if (err < 0)
goto free_cbcpu_mask;
return 0;
free_cbcpu_mask:
free_cpumask_var(pd->cpumask.cbcpu);
free_pcpu_mask:
free_cpumask_var(pd->cpumask.pcpu);
out:
return err;
}
static void __padata_list_init(struct padata_list *pd_list)
{
INIT_LIST_HEAD(&pd_list->list);
spin_lock_init(&pd_list->lock);
}
/* Initialize all percpu queues used by serial workers */
static void padata_init_squeues(struct parallel_data *pd)
{
int cpu;
struct padata_serial_queue *squeue;
for_each_cpu(cpu, pd->cpumask.cbcpu) {
squeue = per_cpu_ptr(pd->squeue, cpu);
squeue->pd = pd;
__padata_list_init(&squeue->serial);
INIT_WORK(&squeue->work, padata_serial_worker);
}
}
/* Initialize all percpu queues used by parallel workers */
static void padata_init_pqueues(struct parallel_data *pd)
{
int cpu;
struct padata_parallel_queue *pqueue;
for_each_cpu(cpu, pd->cpumask.pcpu) {
pqueue = per_cpu_ptr(pd->pqueue, cpu);
__padata_list_init(&pqueue->reorder);
__padata_list_init(&pqueue->parallel);
INIT_WORK(&pqueue->work, padata_parallel_worker);
atomic_set(&pqueue->num_obj, 0);
}
}
/* Allocate and initialize the internal cpumask dependend resources. */
static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
const struct cpumask *pcpumask,
const struct cpumask *cbcpumask)
{
struct parallel_data *pd;
pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
if (!pd)
goto err;
pd->pqueue = alloc_percpu(struct padata_parallel_queue);
if (!pd->pqueue)
goto err_free_pd;
pd->squeue = alloc_percpu(struct padata_serial_queue);
if (!pd->squeue)
goto err_free_pqueue;
pd->pinst = pinst;
if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
goto err_free_squeue;
padata_init_pqueues(pd);
padata_init_squeues(pd);
atomic_set(&pd->seq_nr, -1);
atomic_set(&pd->reorder_objects, 0);
atomic_set(&pd->refcnt, 0);
spin_lock_init(&pd->lock);
pd->cpu = cpumask_first(pd->cpumask.pcpu);
INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
return pd;
err_free_squeue:
free_percpu(pd->squeue);
err_free_pqueue:
free_percpu(pd->pqueue);
err_free_pd:
kfree(pd);
err:
return NULL;
}
static void padata_free_pd(struct parallel_data *pd)
{
free_cpumask_var(pd->cpumask.pcpu);
free_cpumask_var(pd->cpumask.cbcpu);
free_percpu(pd->pqueue);
free_percpu(pd->squeue);
kfree(pd);
}
/* Flush all objects out of the padata queues. */
static void padata_flush_queues(struct parallel_data *pd)
{
int cpu;
struct padata_parallel_queue *pqueue;
struct padata_serial_queue *squeue;
for_each_cpu(cpu, pd->cpumask.pcpu) {
pqueue = per_cpu_ptr(pd->pqueue, cpu);
flush_work(&pqueue->work);
}
if (atomic_read(&pd->reorder_objects))
padata_reorder(pd);
for_each_cpu(cpu, pd->cpumask.cbcpu) {
squeue = per_cpu_ptr(pd->squeue, cpu);
flush_work(&squeue->work);
}
BUG_ON(atomic_read(&pd->refcnt) != 0);
}
static void __padata_start(struct padata_instance *pinst)
{
pinst->flags |= PADATA_INIT;
}
static void __padata_stop(struct padata_instance *pinst)
{
if (!(pinst->flags & PADATA_INIT))
return;
pinst->flags &= ~PADATA_INIT;
synchronize_rcu();
get_online_cpus();
padata_flush_queues(pinst->pd);
put_online_cpus();
}
/* Replace the internal control structure with a new one. */
static void padata_replace(struct padata_instance *pinst,
struct parallel_data *pd_new)
{
struct parallel_data *pd_old = pinst->pd;
int notification_mask = 0;
pinst->flags |= PADATA_RESET;
rcu_assign_pointer(pinst->pd, pd_new);
synchronize_rcu();
if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
notification_mask |= PADATA_CPU_PARALLEL;
if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
notification_mask |= PADATA_CPU_SERIAL;
padata_flush_queues(pd_old);
padata_free_pd(pd_old);
if (notification_mask)
blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
notification_mask,
&pd_new->cpumask);
pinst->flags &= ~PADATA_RESET;
}
/**
* padata_register_cpumask_notifier - Registers a notifier that will be called
* if either pcpu or cbcpu or both cpumasks change.
*
* @pinst: A poineter to padata instance
* @nblock: A pointer to notifier block.
*/
int padata_register_cpumask_notifier(struct padata_instance *pinst,
struct notifier_block *nblock)
{
return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
nblock);
}
EXPORT_SYMBOL(padata_register_cpumask_notifier);
/**
* padata_unregister_cpumask_notifier - Unregisters cpumask notifier
* registered earlier using padata_register_cpumask_notifier
*
* @pinst: A pointer to data instance.
* @nlock: A pointer to notifier block.
*/
int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
struct notifier_block *nblock)
{
return blocking_notifier_chain_unregister(
&pinst->cpumask_change_notifier,
nblock);
}
EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
/* If cpumask contains no active cpu, we mark the instance as invalid. */
static bool padata_validate_cpumask(struct padata_instance *pinst,
const struct cpumask *cpumask)
{
if (!cpumask_intersects(cpumask, cpu_online_mask)) {
pinst->flags |= PADATA_INVALID;
return false;
}
pinst->flags &= ~PADATA_INVALID;
return true;
}
static int __padata_set_cpumasks(struct padata_instance *pinst,
cpumask_var_t pcpumask,
cpumask_var_t cbcpumask)
{
int valid;
struct parallel_data *pd;
valid = padata_validate_cpumask(pinst, pcpumask);
if (!valid) {
__padata_stop(pinst);
goto out_replace;
}
valid = padata_validate_cpumask(pinst, cbcpumask);
if (!valid)
__padata_stop(pinst);
out_replace:
pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
if (!pd)
return -ENOMEM;
cpumask_copy(pinst->cpumask.pcpu, pcpumask);
cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
padata_replace(pinst, pd);
if (valid)
__padata_start(pinst);
return 0;
}
/**
* padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
* equivalent to @cpumask.
*
* @pinst: padata instance
* @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
* to parallel and serial cpumasks respectively.
* @cpumask: the cpumask to use
*/
int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
cpumask_var_t cpumask)
{
struct cpumask *serial_mask, *parallel_mask;
int err = -EINVAL;
mutex_lock(&pinst->lock);
get_online_cpus();
switch (cpumask_type) {
case PADATA_CPU_PARALLEL:
serial_mask = pinst->cpumask.cbcpu;
parallel_mask = cpumask;
break;
case PADATA_CPU_SERIAL:
parallel_mask = pinst->cpumask.pcpu;
serial_mask = cpumask;
break;
default:
goto out;
}
err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
out:
put_online_cpus();
mutex_unlock(&pinst->lock);
return err;
}
EXPORT_SYMBOL(padata_set_cpumask);
/**
* padata_start - start the parallel processing
*
* @pinst: padata instance to start
*/
int padata_start(struct padata_instance *pinst)
{
int err = 0;
mutex_lock(&pinst->lock);
if (pinst->flags & PADATA_INVALID)
err = -EINVAL;
__padata_start(pinst);
mutex_unlock(&pinst->lock);
return err;
}
EXPORT_SYMBOL(padata_start);
/**
* padata_stop - stop the parallel processing
*
* @pinst: padata instance to stop
*/
void padata_stop(struct padata_instance *pinst)
{
mutex_lock(&pinst->lock);
__padata_stop(pinst);
mutex_unlock(&pinst->lock);
}
EXPORT_SYMBOL(padata_stop);
#ifdef CONFIG_HOTPLUG_CPU
static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
{
struct parallel_data *pd;
if (cpumask_test_cpu(cpu, cpu_online_mask)) {
pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
pinst->cpumask.cbcpu);
if (!pd)
return -ENOMEM;
padata_replace(pinst, pd);
if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
__padata_start(pinst);
}
return 0;
}
static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
{
struct parallel_data *pd = NULL;
if (cpumask_test_cpu(cpu, cpu_online_mask)) {
if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
!padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
__padata_stop(pinst);
pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
pinst->cpumask.cbcpu);
if (!pd)
return -ENOMEM;
padata_replace(pinst, pd);
cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
}
return 0;
}
/**
* padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
* padata cpumasks.
*
* @pinst: padata instance
* @cpu: cpu to remove
* @mask: bitmask specifying from which cpumask @cpu should be removed
* The @mask may be any combination of the following flags:
* PADATA_CPU_SERIAL - serial cpumask
* PADATA_CPU_PARALLEL - parallel cpumask
*/
int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
{
int err;
if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
return -EINVAL;
mutex_lock(&pinst->lock);
get_online_cpus();
if (mask & PADATA_CPU_SERIAL)
cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
if (mask & PADATA_CPU_PARALLEL)
cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
err = __padata_remove_cpu(pinst, cpu);
put_online_cpus();
mutex_unlock(&pinst->lock);
return err;
}
EXPORT_SYMBOL(padata_remove_cpu);
static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
{
return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
}
static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
{
struct padata_instance *pinst;
int ret;
pinst = hlist_entry_safe(node, struct padata_instance, node);
if (!pinst_has_cpu(pinst, cpu))
return 0;
mutex_lock(&pinst->lock);
ret = __padata_add_cpu(pinst, cpu);
mutex_unlock(&pinst->lock);
return ret;
}
static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node)
{
struct padata_instance *pinst;
int ret;
pinst = hlist_entry_safe(node, struct padata_instance, node);
if (!pinst_has_cpu(pinst, cpu))
return 0;
mutex_lock(&pinst->lock);
ret = __padata_remove_cpu(pinst, cpu);
mutex_unlock(&pinst->lock);
return ret;
}
static enum cpuhp_state hp_online;
#endif
static void __padata_free(struct padata_instance *pinst)
{
#ifdef CONFIG_HOTPLUG_CPU
cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node);
#endif
padata_stop(pinst);
padata_free_pd(pinst->pd);
free_cpumask_var(pinst->cpumask.pcpu);
free_cpumask_var(pinst->cpumask.cbcpu);
destroy_workqueue(pinst->serial_wq);
destroy_workqueue(pinst->parallel_wq);
kfree(pinst);
}
#define kobj2pinst(_kobj) \
container_of(_kobj, struct padata_instance, kobj)
#define attr2pentry(_attr) \
container_of(_attr, struct padata_sysfs_entry, attr)
static void padata_sysfs_release(struct kobject *kobj)
{
struct padata_instance *pinst = kobj2pinst(kobj);
__padata_free(pinst);
}
struct padata_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
ssize_t (*store)(struct padata_instance *, struct attribute *,
const char *, size_t);
};
static ssize_t show_cpumask(struct padata_instance *pinst,
struct attribute *attr, char *buf)
{
struct cpumask *cpumask;
ssize_t len;
mutex_lock(&pinst->lock);
if (!strcmp(attr->name, "serial_cpumask"))
cpumask = pinst->cpumask.cbcpu;
else
cpumask = pinst->cpumask.pcpu;
len = snprintf(buf, PAGE_SIZE, "%*pb\n",
nr_cpu_ids, cpumask_bits(cpumask));
mutex_unlock(&pinst->lock);
return len < PAGE_SIZE ? len : -EINVAL;
}
static ssize_t store_cpumask(struct padata_instance *pinst,
struct attribute *attr,
const char *buf, size_t count)
{
cpumask_var_t new_cpumask;
ssize_t ret;
int mask_type;
if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
return -ENOMEM;
ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
nr_cpumask_bits);
if (ret < 0)
goto out;
mask_type = !strcmp(attr->name, "serial_cpumask") ?
PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
if (!ret)
ret = count;
out:
free_cpumask_var(new_cpumask);
return ret;
}
#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
static struct padata_sysfs_entry _name##_attr = \
__ATTR(_name, 0644, _show_name, _store_name)
#define PADATA_ATTR_RO(_name, _show_name) \
static struct padata_sysfs_entry _name##_attr = \
__ATTR(_name, 0400, _show_name, NULL)
PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
/*
* Padata sysfs provides the following objects:
* serial_cpumask [RW] - cpumask for serial workers
* parallel_cpumask [RW] - cpumask for parallel workers
*/
static struct attribute *padata_default_attrs[] = {
&serial_cpumask_attr.attr,
&parallel_cpumask_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(padata_default);
static ssize_t padata_sysfs_show(struct kobject *kobj,
struct attribute *attr, char *buf)
{
struct padata_instance *pinst;
struct padata_sysfs_entry *pentry;
ssize_t ret = -EIO;
pinst = kobj2pinst(kobj);
pentry = attr2pentry(attr);
if (pentry->show)
ret = pentry->show(pinst, attr, buf);
return ret;
}
static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t count)
{
struct padata_instance *pinst;
struct padata_sysfs_entry *pentry;
ssize_t ret = -EIO;
pinst = kobj2pinst(kobj);
pentry = attr2pentry(attr);
if (pentry->show)
ret = pentry->store(pinst, attr, buf, count);
return ret;
}
static const struct sysfs_ops padata_sysfs_ops = {
.show = padata_sysfs_show,
.store = padata_sysfs_store,
};
static struct kobj_type padata_attr_type = {
.sysfs_ops = &padata_sysfs_ops,
.default_groups = padata_default_groups,
.release = padata_sysfs_release,
};
/**
* padata_alloc - allocate and initialize a padata instance and specify
* cpumasks for serial and parallel workers.
*
* @name: used to identify the instance
* @pcpumask: cpumask that will be used for padata parallelization
* @cbcpumask: cpumask that will be used for padata serialization
*/
static struct padata_instance *padata_alloc(const char *name,
const struct cpumask *pcpumask,
const struct cpumask *cbcpumask)
{
struct padata_instance *pinst;
struct parallel_data *pd = NULL;
pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
if (!pinst)
goto err;
pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_UNBOUND, 0,
name);
if (!pinst->parallel_wq)
goto err_free_inst;
get_online_cpus();
pinst->serial_wq = alloc_workqueue("%s_serial", WQ_MEM_RECLAIM |
WQ_CPU_INTENSIVE, 1, name);
if (!pinst->serial_wq)
goto err_put_cpus;
if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
goto err_free_serial_wq;
if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
free_cpumask_var(pinst->cpumask.pcpu);
goto err_free_serial_wq;
}
if (!padata_validate_cpumask(pinst, pcpumask) ||
!padata_validate_cpumask(pinst, cbcpumask))
goto err_free_masks;
pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
if (!pd)
goto err_free_masks;
rcu_assign_pointer(pinst->pd, pd);
cpumask_copy(pinst->cpumask.pcpu, pcpumask);
cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
pinst->flags = 0;
BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
kobject_init(&pinst->kobj, &padata_attr_type);
mutex_init(&pinst->lock);
#ifdef CONFIG_HOTPLUG_CPU
cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
#endif
put_online_cpus();
return pinst;
err_free_masks:
free_cpumask_var(pinst->cpumask.pcpu);
free_cpumask_var(pinst->cpumask.cbcpu);
err_free_serial_wq:
destroy_workqueue(pinst->serial_wq);
err_put_cpus:
put_online_cpus();
destroy_workqueue(pinst->parallel_wq);
err_free_inst:
kfree(pinst);
err:
return NULL;
}
/**
* padata_alloc_possible - Allocate and initialize padata instance.
* Use the cpu_possible_mask for serial and
* parallel workers.
*
* @name: used to identify the instance
*/
struct padata_instance *padata_alloc_possible(const char *name)
{
return padata_alloc(name, cpu_possible_mask, cpu_possible_mask);
}
EXPORT_SYMBOL(padata_alloc_possible);
/**
* padata_free - free a padata instance
*
* @padata_inst: padata instance to free
*/
void padata_free(struct padata_instance *pinst)
{
kobject_put(&pinst->kobj);
}
EXPORT_SYMBOL(padata_free);
#ifdef CONFIG_HOTPLUG_CPU
static __init int padata_driver_init(void)
{
int ret;
ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
padata_cpu_online,
padata_cpu_prep_down);
if (ret < 0)
return ret;
hp_online = ret;
return 0;
}
module_init(padata_driver_init);
static __exit void padata_driver_exit(void)
{
cpuhp_remove_multi_state(hp_online);
}
module_exit(padata_driver_exit);
#endif