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linux
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padata.c
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// 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_index, cpu; struct padata_parallel_queue *pqueue; cpu_index = 0; for_each_possible_cpu(cpu) { pqueue = per_cpu_ptr(pd->pqueue, cpu); if (!cpumask_test_cpu(cpu, pd->cpumask.pcpu)) { pqueue->cpu_index = -1; continue; } 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; 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, ¶llel_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
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