linux/kernel/padata.c
Steffen Klassert 2dc9b5dbde padata: Fix race on sequence number wrap
When padata_do_parallel() is called from multiple cpus for the same
padata instance, we can get object reordering on sequence number wrap
because testing for sequence number wrap and reseting the sequence
number must happen atomically but is implemented with two atomic
operations. This patch fixes this by converting the sequence number
from atomic_t to an unsigned int and protect the access with a
spin_lock. As a side effect, we get rid of the sequence number wrap
handling because the seqence number wraps back to null now without
the need to do anything.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2012-03-14 17:25:56 +08:00

1120 lines
27 KiB
C

/*
* padata.c - generic interface to process data streams in parallel
*
* 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>
#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)
{
int cpu_index;
/*
* Hash the sequence numbers to the cpus by taking
* seq_nr mod. number of cpus in use.
*/
spin_lock(&pd->seq_lock);
cpu_index = pd->seq_nr % cpumask_weight(pd->cpumask.pcpu);
pd->seq_nr++;
spin_unlock(&pd->seq_lock);
return padata_index_to_cpu(pd, cpu_index);
}
static void padata_parallel_worker(struct work_struct *parallel_work)
{
struct padata_parallel_queue *pqueue;
struct parallel_data *pd;
struct padata_instance *pinst;
LIST_HEAD(local_list);
local_bh_disable();
pqueue = container_of(parallel_work,
struct padata_parallel_queue, work);
pd = pqueue->pd;
pinst = pd->pinst;
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: cpu the serialization callback function will run on,
* must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
*
* 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 target_cpu, err;
struct padata_parallel_queue *queue;
struct parallel_data *pd;
rcu_read_lock_bh();
pd = rcu_dereference(pinst->pd);
err = -EINVAL;
if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
goto out;
if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))
goto out;
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;
target_cpu = padata_cpu_hash(pd);
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_on(target_cpu, pinst->wq, &queue->work);
out:
rcu_read_unlock_bh();
return err;
}
EXPORT_SYMBOL(padata_do_parallel);
/*
* padata_get_next - Get 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 all percpu reorder queues are empty.
*
* -EINPROGRESS, 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.
*
* -ENODATA, if this cpu has to do the parallel processing for
* the next object.
*/
static struct padata_priv *padata_get_next(struct parallel_data *pd)
{
int cpu, num_cpus;
unsigned int next_nr, next_index;
struct padata_parallel_queue *queue, *next_queue;
struct padata_priv *padata;
struct padata_list *reorder;
num_cpus = cpumask_weight(pd->cpumask.pcpu);
/*
* Calculate the percpu reorder queue and the sequence
* number of the next object.
*/
next_nr = pd->processed;
next_index = next_nr % num_cpus;
cpu = padata_index_to_cpu(pd, next_index);
next_queue = per_cpu_ptr(pd->pqueue, cpu);
padata = NULL;
reorder = &next_queue->reorder;
if (!list_empty(&reorder->list)) {
padata = list_entry(reorder->list.next,
struct padata_priv, list);
spin_lock(&reorder->lock);
list_del_init(&padata->list);
atomic_dec(&pd->reorder_objects);
spin_unlock(&reorder->lock);
pd->processed++;
goto out;
}
queue = per_cpu_ptr(pd->pqueue, smp_processor_id());
if (queue->cpu_index == next_queue->cpu_index) {
padata = ERR_PTR(-ENODATA);
goto out;
}
padata = ERR_PTR(-EINPROGRESS);
out:
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;
/*
* 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_get_next(pd);
/*
* All reorder queues are empty, or 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 || PTR_ERR(padata) == -EINPROGRESS)
break;
/*
* This cpu has to do the parallel processing of the next
* object. It's waiting in the cpu's parallelization queue,
* so exit immediately.
*/
if (PTR_ERR(padata) == -ENODATA) {
del_timer(&pd->timer);
spin_unlock_bh(&pd->lock);
return;
}
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->wq, &squeue->work);
}
spin_unlock_bh(&pd->lock);
/*
* The next object that needs serialization might have arrived to
* the reorder queues in the meantime, we will be called again
* from the timer function if no one else cares for it.
*/
if (atomic_read(&pd->reorder_objects)
&& !(pinst->flags & PADATA_RESET))
mod_timer(&pd->timer, jiffies + HZ);
else
del_timer(&pd->timer);
return;
}
static void padata_reorder_timer(unsigned long arg)
{
struct parallel_data *pd = (struct parallel_data *)arg;
padata_reorder(pd);
}
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)
{
int cpu;
struct padata_parallel_queue *pqueue;
struct parallel_data *pd;
pd = padata->pd;
cpu = get_cpu();
pqueue = per_cpu_ptr(pd->pqueue, cpu);
spin_lock(&pqueue->reorder.lock);
atomic_inc(&pd->reorder_objects);
list_add_tail(&padata->list, &pqueue->reorder.list);
spin_unlock(&pqueue->reorder.lock);
put_cpu();
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)
{
if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
return -ENOMEM;
cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_active_mask);
if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
free_cpumask_var(pd->cpumask.cbcpu);
return -ENOMEM;
}
cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_active_mask);
return 0;
}
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_index, cpu;
struct padata_parallel_queue *pqueue;
cpu_index = 0;
for_each_cpu(cpu, pd->cpumask.pcpu) {
pqueue = per_cpu_ptr(pd->pqueue, cpu);
pqueue->pd = pd;
pqueue->cpu_index = cpu_index;
cpu_index++;
__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;
if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
goto err_free_squeue;
padata_init_pqueues(pd);
padata_init_squeues(pd);
setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
pd->seq_nr = 0;
atomic_set(&pd->reorder_objects, 0);
atomic_set(&pd->refcnt, 0);
pd->pinst = pinst;
spin_lock_init(&pd->lock);
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);
}
del_timer_sync(&pd->timer);
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_active_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_cpumasks - Set both parallel and serial cpumasks. The first
* one is used by parallel workers and the second one
* by the wokers doing serialization.
*
* @pinst: padata instance
* @pcpumask: the cpumask to use for parallel workers
* @cbcpumask: the cpumsak to use for serial workers
*/
int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask,
cpumask_var_t cbcpumask)
{
int err;
mutex_lock(&pinst->lock);
get_online_cpus();
err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask);
put_online_cpus();
mutex_unlock(&pinst->lock);
return err;
}
EXPORT_SYMBOL(padata_set_cpumasks);
/**
* 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);
static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
{
struct parallel_data *pd;
if (cpumask_test_cpu(cpu, cpu_active_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;
}
/**
* padata_add_cpu - add a cpu to one or both(parallel and serial)
* padata cpumasks.
*
* @pinst: padata instance
* @cpu: cpu to add
* @mask: bitmask of flags specifying to which cpumask @cpu shuld be added.
* The @mask may be any combination of the following flags:
* PADATA_CPU_SERIAL - serial cpumask
* PADATA_CPU_PARALLEL - parallel cpumask
*/
int padata_add_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_set_cpu(cpu, pinst->cpumask.cbcpu);
if (mask & PADATA_CPU_PARALLEL)
cpumask_set_cpu(cpu, pinst->cpumask.pcpu);
err = __padata_add_cpu(pinst, cpu);
put_online_cpus();
mutex_unlock(&pinst->lock);
return err;
}
EXPORT_SYMBOL(padata_add_cpu);
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);
}
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);
/**
* 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 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_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
int err;
struct padata_instance *pinst;
int cpu = (unsigned long)hcpu;
pinst = container_of(nfb, struct padata_instance, cpu_notifier);
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
if (!pinst_has_cpu(pinst, cpu))
break;
mutex_lock(&pinst->lock);
err = __padata_add_cpu(pinst, cpu);
mutex_unlock(&pinst->lock);
if (err)
return notifier_from_errno(err);
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
if (!pinst_has_cpu(pinst, cpu))
break;
mutex_lock(&pinst->lock);
err = __padata_remove_cpu(pinst, cpu);
mutex_unlock(&pinst->lock);
if (err)
return notifier_from_errno(err);
break;
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
if (!pinst_has_cpu(pinst, cpu))
break;
mutex_lock(&pinst->lock);
__padata_remove_cpu(pinst, cpu);
mutex_unlock(&pinst->lock);
case CPU_DOWN_FAILED:
case CPU_DOWN_FAILED_FROZEN:
if (!pinst_has_cpu(pinst, cpu))
break;
mutex_lock(&pinst->lock);
__padata_add_cpu(pinst, cpu);
mutex_unlock(&pinst->lock);
}
return NOTIFY_OK;
}
#endif
static void __padata_free(struct padata_instance *pinst)
{
#ifdef CONFIG_HOTPLUG_CPU
unregister_hotcpu_notifier(&pinst->cpu_notifier);
#endif
padata_stop(pinst);
padata_free_pd(pinst->pd);
free_cpumask_var(pinst->cpumask.pcpu);
free_cpumask_var(pinst->cpumask.cbcpu);
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 = bitmap_scnprintf(buf, PAGE_SIZE, cpumask_bits(cpumask),
nr_cpu_ids);
if (PAGE_SIZE - len < 2)
len = -EINVAL;
else
len += sprintf(buf + len, "\n");
mutex_unlock(&pinst->lock);
return len;
}
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,
};
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_attrs = padata_default_attrs,
.release = padata_sysfs_release,
};
/**
* padata_alloc_possible - Allocate and initialize padata instance.
* Use the cpu_possible_mask for serial and
* parallel workers.
*
* @wq: workqueue to use for the allocated padata instance
*/
struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
{
return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
}
EXPORT_SYMBOL(padata_alloc_possible);
/**
* padata_alloc - allocate and initialize a padata instance and specify
* cpumasks for serial and parallel workers.
*
* @wq: workqueue to use for the allocated padata instance
* @pcpumask: cpumask that will be used for padata parallelization
* @cbcpumask: cpumask that will be used for padata serialization
*/
struct padata_instance *padata_alloc(struct workqueue_struct *wq,
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;
get_online_cpus();
if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
goto err_free_inst;
if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
free_cpumask_var(pinst->cpumask.pcpu);
goto err_free_inst;
}
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);
pinst->wq = wq;
cpumask_copy(pinst->cpumask.pcpu, pcpumask);
cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
pinst->flags = 0;
#ifdef CONFIG_HOTPLUG_CPU
pinst->cpu_notifier.notifier_call = padata_cpu_callback;
pinst->cpu_notifier.priority = 0;
register_hotcpu_notifier(&pinst->cpu_notifier);
#endif
put_online_cpus();
BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
kobject_init(&pinst->kobj, &padata_attr_type);
mutex_init(&pinst->lock);
return pinst;
err_free_masks:
free_cpumask_var(pinst->cpumask.pcpu);
free_cpumask_var(pinst->cpumask.cbcpu);
err_free_inst:
kfree(pinst);
put_online_cpus();
err:
return NULL;
}
EXPORT_SYMBOL(padata_alloc);
/**
* 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);