--- /dev/null
+/*
+ * 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>
+
+#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;
+ int cpu_index;
+
+ /*
+ * Hash the sequence numbers to the cpus by taking
+ * seq_nr mod. number of cpus in use.
+ */
+
+ seq_nr = atomic_inc_return(&pd->seq_nr);
+ 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;
+ 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_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))
+ 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 *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;
+ }
+
+ if (__this_cpu_read(pd->pqueue->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_online_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_online_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);
+ atomic_set(&pd->seq_nr, -1);
+ 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_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_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_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;
+}
+
+ /**
+ * 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);
+
+ 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);
+
+/**
+ * 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:
+ case CPU_DOWN_FAILED:
+ case CPU_DOWN_FAILED_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:
+ case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_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;
+ }
+
+ 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 = 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,
+ ¶llel_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;
+
+ put_online_cpus();
+
+ BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
+ kobject_init(&pinst->kobj, &padata_attr_type);
+ mutex_init(&pinst->lock);
+
+#ifdef CONFIG_HOTPLUG_CPU
+ pinst->cpu_notifier.notifier_call = padata_cpu_callback;
+ pinst->cpu_notifier.priority = 0;
+ register_hotcpu_notifier(&pinst->cpu_notifier);
+#endif
+
+ 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);
Code Review / kvmfornfv.git / blobdiff