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1141 lines
27 KiB
1141 lines
27 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* padata.c - generic interface to process data streams in parallel |
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* |
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* See Documentation/core-api/padata.rst for more information. |
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* |
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* Copyright (C) 2008, 2009 secunet Security Networks AG |
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* Copyright (C) 2008, 2009 Steffen Klassert <[email protected]> |
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* |
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* Copyright (c) 2020 Oracle and/or its affiliates. |
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* Author: Daniel Jordan <[email protected]> |
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*/ |
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|
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#include <linux/completion.h> |
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#include <linux/export.h> |
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#include <linux/cpumask.h> |
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#include <linux/err.h> |
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#include <linux/cpu.h> |
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#include <linux/padata.h> |
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#include <linux/mutex.h> |
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#include <linux/sched.h> |
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#include <linux/slab.h> |
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#include <linux/sysfs.h> |
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#include <linux/rcupdate.h> |
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#define PADATA_WORK_ONSTACK 1 /* Work's memory is on stack */ |
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struct padata_work { |
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struct work_struct pw_work; |
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struct list_head pw_list; /* padata_free_works linkage */ |
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void *pw_data; |
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}; |
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|
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static DEFINE_SPINLOCK(padata_works_lock); |
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static struct padata_work *padata_works; |
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static LIST_HEAD(padata_free_works); |
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struct padata_mt_job_state { |
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spinlock_t lock; |
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struct completion completion; |
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struct padata_mt_job *job; |
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int nworks; |
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int nworks_fini; |
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unsigned long chunk_size; |
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}; |
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|
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static void padata_free_pd(struct parallel_data *pd); |
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static void __init padata_mt_helper(struct work_struct *work); |
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static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index) |
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{ |
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int cpu, target_cpu; |
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target_cpu = cpumask_first(pd->cpumask.pcpu); |
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for (cpu = 0; cpu < cpu_index; cpu++) |
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target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu); |
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return target_cpu; |
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} |
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|
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static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr) |
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{ |
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/* |
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* Hash the sequence numbers to the cpus by taking |
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* seq_nr mod. number of cpus in use. |
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*/ |
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int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu); |
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|
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return padata_index_to_cpu(pd, cpu_index); |
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} |
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static struct padata_work *padata_work_alloc(void) |
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{ |
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struct padata_work *pw; |
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lockdep_assert_held(&padata_works_lock); |
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|
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if (list_empty(&padata_free_works)) |
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return NULL; /* No more work items allowed to be queued. */ |
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pw = list_first_entry(&padata_free_works, struct padata_work, pw_list); |
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list_del(&pw->pw_list); |
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return pw; |
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} |
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static void padata_work_init(struct padata_work *pw, work_func_t work_fn, |
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void *data, int flags) |
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{ |
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if (flags & PADATA_WORK_ONSTACK) |
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INIT_WORK_ONSTACK(&pw->pw_work, work_fn); |
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else |
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INIT_WORK(&pw->pw_work, work_fn); |
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pw->pw_data = data; |
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} |
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static int __init padata_work_alloc_mt(int nworks, void *data, |
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struct list_head *head) |
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{ |
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int i; |
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spin_lock(&padata_works_lock); |
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/* Start at 1 because the current task participates in the job. */ |
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for (i = 1; i < nworks; ++i) { |
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struct padata_work *pw = padata_work_alloc(); |
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|
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if (!pw) |
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break; |
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padata_work_init(pw, padata_mt_helper, data, 0); |
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list_add(&pw->pw_list, head); |
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} |
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spin_unlock(&padata_works_lock); |
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return i; |
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} |
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static void padata_work_free(struct padata_work *pw) |
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{ |
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lockdep_assert_held(&padata_works_lock); |
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list_add(&pw->pw_list, &padata_free_works); |
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} |
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static void __init padata_works_free(struct list_head *works) |
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{ |
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struct padata_work *cur, *next; |
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|
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if (list_empty(works)) |
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return; |
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spin_lock(&padata_works_lock); |
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list_for_each_entry_safe(cur, next, works, pw_list) { |
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list_del(&cur->pw_list); |
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padata_work_free(cur); |
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} |
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spin_unlock(&padata_works_lock); |
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} |
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static void padata_parallel_worker(struct work_struct *parallel_work) |
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{ |
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struct padata_work *pw = container_of(parallel_work, struct padata_work, |
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pw_work); |
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struct padata_priv *padata = pw->pw_data; |
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local_bh_disable(); |
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padata->parallel(padata); |
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spin_lock(&padata_works_lock); |
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padata_work_free(pw); |
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spin_unlock(&padata_works_lock); |
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local_bh_enable(); |
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} |
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/** |
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* padata_do_parallel - padata parallelization function |
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* |
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* @ps: padatashell |
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* @padata: object to be parallelized |
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* @cb_cpu: pointer to the CPU that the serialization callback function should |
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* run on. If it's not in the serial cpumask of @pinst |
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* (i.e. cpumask.cbcpu), this function selects a fallback CPU and if |
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* none found, returns -EINVAL. |
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* |
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* The parallelization callback function will run with BHs off. |
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* Note: Every object which is parallelized by padata_do_parallel |
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* must be seen by padata_do_serial. |
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* |
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* Return: 0 on success or else negative error code. |
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*/ |
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int padata_do_parallel(struct padata_shell *ps, |
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struct padata_priv *padata, int *cb_cpu) |
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{ |
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struct padata_instance *pinst = ps->pinst; |
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int i, cpu, cpu_index, err; |
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struct parallel_data *pd; |
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struct padata_work *pw; |
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rcu_read_lock_bh(); |
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pd = rcu_dereference_bh(ps->pd); |
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err = -EINVAL; |
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if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID) |
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goto out; |
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if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) { |
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if (!cpumask_weight(pd->cpumask.cbcpu)) |
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goto out; |
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/* Select an alternate fallback CPU and notify the caller. */ |
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cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu); |
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cpu = cpumask_first(pd->cpumask.cbcpu); |
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for (i = 0; i < cpu_index; i++) |
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cpu = cpumask_next(cpu, pd->cpumask.cbcpu); |
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*cb_cpu = cpu; |
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} |
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err = -EBUSY; |
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if ((pinst->flags & PADATA_RESET)) |
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goto out; |
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refcount_inc(&pd->refcnt); |
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padata->pd = pd; |
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padata->cb_cpu = *cb_cpu; |
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spin_lock(&padata_works_lock); |
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padata->seq_nr = ++pd->seq_nr; |
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pw = padata_work_alloc(); |
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spin_unlock(&padata_works_lock); |
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rcu_read_unlock_bh(); |
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if (pw) { |
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padata_work_init(pw, padata_parallel_worker, padata, 0); |
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queue_work(pinst->parallel_wq, &pw->pw_work); |
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} else { |
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/* Maximum works limit exceeded, run in the current task. */ |
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padata->parallel(padata); |
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} |
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return 0; |
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out: |
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rcu_read_unlock_bh(); |
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return err; |
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} |
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EXPORT_SYMBOL(padata_do_parallel); |
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/* |
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* padata_find_next - Find the next object that needs serialization. |
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* |
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* Return: |
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* * A pointer to the control struct of the next object that needs |
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* serialization, if present in one of the percpu reorder queues. |
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* * NULL, if the next object that needs serialization will |
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* be parallel processed by another cpu and is not yet present in |
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* the cpu's reorder queue. |
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*/ |
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static struct padata_priv *padata_find_next(struct parallel_data *pd, |
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bool remove_object) |
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{ |
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struct padata_priv *padata; |
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struct padata_list *reorder; |
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int cpu = pd->cpu; |
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reorder = per_cpu_ptr(pd->reorder_list, cpu); |
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spin_lock(&reorder->lock); |
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if (list_empty(&reorder->list)) { |
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spin_unlock(&reorder->lock); |
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return NULL; |
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} |
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padata = list_entry(reorder->list.next, struct padata_priv, list); |
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/* |
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* Checks the rare case where two or more parallel jobs have hashed to |
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* the same CPU and one of the later ones finishes first. |
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*/ |
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if (padata->seq_nr != pd->processed) { |
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spin_unlock(&reorder->lock); |
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return NULL; |
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} |
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if (remove_object) { |
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list_del_init(&padata->list); |
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++pd->processed; |
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pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false); |
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} |
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spin_unlock(&reorder->lock); |
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return padata; |
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} |
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static void padata_reorder(struct parallel_data *pd) |
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{ |
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struct padata_instance *pinst = pd->ps->pinst; |
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int cb_cpu; |
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struct padata_priv *padata; |
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struct padata_serial_queue *squeue; |
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struct padata_list *reorder; |
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/* |
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* We need to ensure that only one cpu can work on dequeueing of |
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* the reorder queue the time. Calculating in which percpu reorder |
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* queue the next object will arrive takes some time. A spinlock |
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* would be highly contended. Also it is not clear in which order |
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* the objects arrive to the reorder queues. So a cpu could wait to |
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* get the lock just to notice that there is nothing to do at the |
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* moment. Therefore we use a trylock and let the holder of the lock |
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* care for all the objects enqueued during the holdtime of the lock. |
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*/ |
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if (!spin_trylock_bh(&pd->lock)) |
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return; |
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while (1) { |
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padata = padata_find_next(pd, true); |
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/* |
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* If the next object that needs serialization is parallel |
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* processed by another cpu and is still on it's way to the |
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* cpu's reorder queue, nothing to do for now. |
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*/ |
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if (!padata) |
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break; |
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cb_cpu = padata->cb_cpu; |
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squeue = per_cpu_ptr(pd->squeue, cb_cpu); |
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spin_lock(&squeue->serial.lock); |
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list_add_tail(&padata->list, &squeue->serial.list); |
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spin_unlock(&squeue->serial.lock); |
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queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work); |
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} |
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spin_unlock_bh(&pd->lock); |
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/* |
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* The next object that needs serialization might have arrived to |
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* the reorder queues in the meantime. |
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* |
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* Ensure reorder queue is read after pd->lock is dropped so we see |
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* new objects from another task in padata_do_serial. Pairs with |
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* smp_mb in padata_do_serial. |
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*/ |
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smp_mb(); |
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reorder = per_cpu_ptr(pd->reorder_list, pd->cpu); |
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if (!list_empty(&reorder->list) && padata_find_next(pd, false)) |
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queue_work(pinst->serial_wq, &pd->reorder_work); |
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} |
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static void invoke_padata_reorder(struct work_struct *work) |
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{ |
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struct parallel_data *pd; |
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local_bh_disable(); |
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pd = container_of(work, struct parallel_data, reorder_work); |
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padata_reorder(pd); |
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local_bh_enable(); |
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} |
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static void padata_serial_worker(struct work_struct *serial_work) |
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{ |
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struct padata_serial_queue *squeue; |
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struct parallel_data *pd; |
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LIST_HEAD(local_list); |
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int cnt; |
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local_bh_disable(); |
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squeue = container_of(serial_work, struct padata_serial_queue, work); |
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pd = squeue->pd; |
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spin_lock(&squeue->serial.lock); |
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list_replace_init(&squeue->serial.list, &local_list); |
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spin_unlock(&squeue->serial.lock); |
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cnt = 0; |
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while (!list_empty(&local_list)) { |
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struct padata_priv *padata; |
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padata = list_entry(local_list.next, |
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struct padata_priv, list); |
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list_del_init(&padata->list); |
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|
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padata->serial(padata); |
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cnt++; |
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} |
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local_bh_enable(); |
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|
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if (refcount_sub_and_test(cnt, &pd->refcnt)) |
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padata_free_pd(pd); |
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} |
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|
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/** |
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* padata_do_serial - padata serialization function |
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* |
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* @padata: object to be serialized. |
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* |
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* padata_do_serial must be called for every parallelized object. |
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* The serialization callback function will run with BHs off. |
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*/ |
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void padata_do_serial(struct padata_priv *padata) |
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{ |
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struct parallel_data *pd = padata->pd; |
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int hashed_cpu = padata_cpu_hash(pd, padata->seq_nr); |
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struct padata_list *reorder = per_cpu_ptr(pd->reorder_list, hashed_cpu); |
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struct padata_priv *cur; |
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|
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spin_lock(&reorder->lock); |
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/* Sort in ascending order of sequence number. */ |
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list_for_each_entry_reverse(cur, &reorder->list, list) |
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if (cur->seq_nr < padata->seq_nr) |
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break; |
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list_add(&padata->list, &cur->list); |
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spin_unlock(&reorder->lock); |
|
|
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/* |
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* Ensure the addition to the reorder list is ordered correctly |
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* with the trylock of pd->lock in padata_reorder. Pairs with smp_mb |
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* in padata_reorder. |
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*/ |
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smp_mb(); |
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|
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padata_reorder(pd); |
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} |
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EXPORT_SYMBOL(padata_do_serial); |
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|
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static int padata_setup_cpumasks(struct padata_instance *pinst) |
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{ |
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struct workqueue_attrs *attrs; |
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int err; |
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|
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attrs = alloc_workqueue_attrs(); |
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if (!attrs) |
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return -ENOMEM; |
|
|
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/* Restrict parallel_wq workers to pd->cpumask.pcpu. */ |
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cpumask_copy(attrs->cpumask, pinst->cpumask.pcpu); |
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err = apply_workqueue_attrs(pinst->parallel_wq, attrs); |
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free_workqueue_attrs(attrs); |
|
|
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return err; |
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} |
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|
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static void __init padata_mt_helper(struct work_struct *w) |
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{ |
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struct padata_work *pw = container_of(w, struct padata_work, pw_work); |
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struct padata_mt_job_state *ps = pw->pw_data; |
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struct padata_mt_job *job = ps->job; |
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bool done; |
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|
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spin_lock(&ps->lock); |
|
|
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while (job->size > 0) { |
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unsigned long start, size, end; |
|
|
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start = job->start; |
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/* So end is chunk size aligned if enough work remains. */ |
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size = roundup(start + 1, ps->chunk_size) - start; |
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size = min(size, job->size); |
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end = start + size; |
|
|
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job->start = end; |
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job->size -= size; |
|
|
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spin_unlock(&ps->lock); |
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job->thread_fn(start, end, job->fn_arg); |
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spin_lock(&ps->lock); |
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} |
|
|
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++ps->nworks_fini; |
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done = (ps->nworks_fini == ps->nworks); |
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spin_unlock(&ps->lock); |
|
|
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if (done) |
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complete(&ps->completion); |
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} |
|
|
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/** |
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* padata_do_multithreaded - run a multithreaded job |
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* @job: Description of the job. |
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* |
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* See the definition of struct padata_mt_job for more details. |
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*/ |
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void __init padata_do_multithreaded(struct padata_mt_job *job) |
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{ |
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/* In case threads finish at different times. */ |
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static const unsigned long load_balance_factor = 4; |
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struct padata_work my_work, *pw; |
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struct padata_mt_job_state ps; |
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LIST_HEAD(works); |
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int nworks; |
|
|
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if (job->size == 0) |
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return; |
|
|
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/* Ensure at least one thread when size < min_chunk. */ |
|
nworks = max(job->size / job->min_chunk, 1ul); |
|
nworks = min(nworks, job->max_threads); |
|
|
|
if (nworks == 1) { |
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/* Single thread, no coordination needed, cut to the chase. */ |
|
job->thread_fn(job->start, job->start + job->size, job->fn_arg); |
|
return; |
|
} |
|
|
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spin_lock_init(&ps.lock); |
|
init_completion(&ps.completion); |
|
ps.job = job; |
|
ps.nworks = padata_work_alloc_mt(nworks, &ps, &works); |
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ps.nworks_fini = 0; |
|
|
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/* |
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* Chunk size is the amount of work a helper does per call to the |
|
* thread function. Load balance large jobs between threads by |
|
* increasing the number of chunks, guarantee at least the minimum |
|
* chunk size from the caller, and honor the caller's alignment. |
|
*/ |
|
ps.chunk_size = job->size / (ps.nworks * load_balance_factor); |
|
ps.chunk_size = max(ps.chunk_size, job->min_chunk); |
|
ps.chunk_size = roundup(ps.chunk_size, job->align); |
|
|
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list_for_each_entry(pw, &works, pw_list) |
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queue_work(system_unbound_wq, &pw->pw_work); |
|
|
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/* Use the current thread, which saves starting a workqueue worker. */ |
|
padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK); |
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padata_mt_helper(&my_work.pw_work); |
|
|
|
/* Wait for all the helpers to finish. */ |
|
wait_for_completion(&ps.completion); |
|
|
|
destroy_work_on_stack(&my_work.pw_work); |
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padata_works_free(&works); |
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} |
|
|
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static void __padata_list_init(struct padata_list *pd_list) |
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{ |
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INIT_LIST_HEAD(&pd_list->list); |
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spin_lock_init(&pd_list->lock); |
|
} |
|
|
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/* 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); |
|
} |
|
} |
|
|
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/* Initialize per-CPU reorder lists */ |
|
static void padata_init_reorder_list(struct parallel_data *pd) |
|
{ |
|
int cpu; |
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struct padata_list *list; |
|
|
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for_each_cpu(cpu, pd->cpumask.pcpu) { |
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list = per_cpu_ptr(pd->reorder_list, cpu); |
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__padata_list_init(list); |
|
} |
|
} |
|
|
|
/* Allocate and initialize the internal cpumask dependend resources. */ |
|
static struct parallel_data *padata_alloc_pd(struct padata_shell *ps) |
|
{ |
|
struct padata_instance *pinst = ps->pinst; |
|
struct parallel_data *pd; |
|
|
|
pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL); |
|
if (!pd) |
|
goto err; |
|
|
|
pd->reorder_list = alloc_percpu(struct padata_list); |
|
if (!pd->reorder_list) |
|
goto err_free_pd; |
|
|
|
pd->squeue = alloc_percpu(struct padata_serial_queue); |
|
if (!pd->squeue) |
|
goto err_free_reorder_list; |
|
|
|
pd->ps = ps; |
|
|
|
if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL)) |
|
goto err_free_squeue; |
|
if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) |
|
goto err_free_pcpu; |
|
|
|
cpumask_and(pd->cpumask.pcpu, pinst->cpumask.pcpu, cpu_online_mask); |
|
cpumask_and(pd->cpumask.cbcpu, pinst->cpumask.cbcpu, cpu_online_mask); |
|
|
|
padata_init_reorder_list(pd); |
|
padata_init_squeues(pd); |
|
pd->seq_nr = -1; |
|
refcount_set(&pd->refcnt, 1); |
|
spin_lock_init(&pd->lock); |
|
pd->cpu = cpumask_first(pd->cpumask.pcpu); |
|
INIT_WORK(&pd->reorder_work, invoke_padata_reorder); |
|
|
|
return pd; |
|
|
|
err_free_pcpu: |
|
free_cpumask_var(pd->cpumask.pcpu); |
|
err_free_squeue: |
|
free_percpu(pd->squeue); |
|
err_free_reorder_list: |
|
free_percpu(pd->reorder_list); |
|
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->reorder_list); |
|
free_percpu(pd->squeue); |
|
kfree(pd); |
|
} |
|
|
|
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(); |
|
} |
|
|
|
/* Replace the internal control structure with a new one. */ |
|
static int padata_replace_one(struct padata_shell *ps) |
|
{ |
|
struct parallel_data *pd_new; |
|
|
|
pd_new = padata_alloc_pd(ps); |
|
if (!pd_new) |
|
return -ENOMEM; |
|
|
|
ps->opd = rcu_dereference_protected(ps->pd, 1); |
|
rcu_assign_pointer(ps->pd, pd_new); |
|
|
|
return 0; |
|
} |
|
|
|
static int padata_replace(struct padata_instance *pinst) |
|
{ |
|
struct padata_shell *ps; |
|
int err = 0; |
|
|
|
pinst->flags |= PADATA_RESET; |
|
|
|
list_for_each_entry(ps, &pinst->pslist, list) { |
|
err = padata_replace_one(ps); |
|
if (err) |
|
break; |
|
} |
|
|
|
synchronize_rcu(); |
|
|
|
list_for_each_entry_continue_reverse(ps, &pinst->pslist, list) |
|
if (refcount_dec_and_test(&ps->opd->refcnt)) |
|
padata_free_pd(ps->opd); |
|
|
|
pinst->flags &= ~PADATA_RESET; |
|
|
|
return err; |
|
} |
|
|
|
/* 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; |
|
int err; |
|
|
|
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: |
|
cpumask_copy(pinst->cpumask.pcpu, pcpumask); |
|
cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); |
|
|
|
err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst); |
|
|
|
if (valid) |
|
__padata_start(pinst); |
|
|
|
return err; |
|
} |
|
|
|
/** |
|
* 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 |
|
* |
|
* Return: 0 on success or negative error code |
|
*/ |
|
int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, |
|
cpumask_var_t cpumask) |
|
{ |
|
struct cpumask *serial_mask, *parallel_mask; |
|
int err = -EINVAL; |
|
|
|
cpus_read_lock(); |
|
mutex_lock(&pinst->lock); |
|
|
|
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: |
|
mutex_unlock(&pinst->lock); |
|
cpus_read_unlock(); |
|
|
|
return err; |
|
} |
|
EXPORT_SYMBOL(padata_set_cpumask); |
|
|
|
#ifdef CONFIG_HOTPLUG_CPU |
|
|
|
static int __padata_add_cpu(struct padata_instance *pinst, int cpu) |
|
{ |
|
int err = 0; |
|
|
|
if (cpumask_test_cpu(cpu, cpu_online_mask)) { |
|
err = padata_replace(pinst); |
|
|
|
if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) && |
|
padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) |
|
__padata_start(pinst); |
|
} |
|
|
|
return err; |
|
} |
|
|
|
static int __padata_remove_cpu(struct padata_instance *pinst, int cpu) |
|
{ |
|
int err = 0; |
|
|
|
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); |
|
|
|
err = padata_replace(pinst); |
|
} |
|
|
|
return err; |
|
} |
|
|
|
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, cpu_online_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_dead(unsigned int cpu, struct hlist_node *node) |
|
{ |
|
struct padata_instance *pinst; |
|
int ret; |
|
|
|
pinst = hlist_entry_safe(node, struct padata_instance, cpu_dead_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(CPUHP_PADATA_DEAD, |
|
&pinst->cpu_dead_node); |
|
cpuhp_state_remove_instance_nocalls(hp_online, &pinst->cpu_online_node); |
|
#endif |
|
|
|
WARN_ON(!list_empty(&pinst->pslist)); |
|
|
|
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 |
|
* @name: used to identify the instance |
|
* |
|
* Return: new instance on success, NULL on error |
|
*/ |
|
struct padata_instance *padata_alloc(const char *name) |
|
{ |
|
struct padata_instance *pinst; |
|
|
|
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; |
|
|
|
cpus_read_lock(); |
|
|
|
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; |
|
} |
|
|
|
INIT_LIST_HEAD(&pinst->pslist); |
|
|
|
cpumask_copy(pinst->cpumask.pcpu, cpu_possible_mask); |
|
cpumask_copy(pinst->cpumask.cbcpu, cpu_possible_mask); |
|
|
|
if (padata_setup_cpumasks(pinst)) |
|
goto err_free_masks; |
|
|
|
__padata_start(pinst); |
|
|
|
kobject_init(&pinst->kobj, &padata_attr_type); |
|
mutex_init(&pinst->lock); |
|
|
|
#ifdef CONFIG_HOTPLUG_CPU |
|
cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, |
|
&pinst->cpu_online_node); |
|
cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD, |
|
&pinst->cpu_dead_node); |
|
#endif |
|
|
|
cpus_read_unlock(); |
|
|
|
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: |
|
cpus_read_unlock(); |
|
destroy_workqueue(pinst->parallel_wq); |
|
err_free_inst: |
|
kfree(pinst); |
|
err: |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL(padata_alloc); |
|
|
|
/** |
|
* padata_free - free a padata instance |
|
* |
|
* @pinst: padata instance to free |
|
*/ |
|
void padata_free(struct padata_instance *pinst) |
|
{ |
|
kobject_put(&pinst->kobj); |
|
} |
|
EXPORT_SYMBOL(padata_free); |
|
|
|
/** |
|
* padata_alloc_shell - Allocate and initialize padata shell. |
|
* |
|
* @pinst: Parent padata_instance object. |
|
* |
|
* Return: new shell on success, NULL on error |
|
*/ |
|
struct padata_shell *padata_alloc_shell(struct padata_instance *pinst) |
|
{ |
|
struct parallel_data *pd; |
|
struct padata_shell *ps; |
|
|
|
ps = kzalloc(sizeof(*ps), GFP_KERNEL); |
|
if (!ps) |
|
goto out; |
|
|
|
ps->pinst = pinst; |
|
|
|
cpus_read_lock(); |
|
pd = padata_alloc_pd(ps); |
|
cpus_read_unlock(); |
|
|
|
if (!pd) |
|
goto out_free_ps; |
|
|
|
mutex_lock(&pinst->lock); |
|
RCU_INIT_POINTER(ps->pd, pd); |
|
list_add(&ps->list, &pinst->pslist); |
|
mutex_unlock(&pinst->lock); |
|
|
|
return ps; |
|
|
|
out_free_ps: |
|
kfree(ps); |
|
out: |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL(padata_alloc_shell); |
|
|
|
/** |
|
* padata_free_shell - free a padata shell |
|
* |
|
* @ps: padata shell to free |
|
*/ |
|
void padata_free_shell(struct padata_shell *ps) |
|
{ |
|
if (!ps) |
|
return; |
|
|
|
mutex_lock(&ps->pinst->lock); |
|
list_del(&ps->list); |
|
padata_free_pd(rcu_dereference_protected(ps->pd, 1)); |
|
mutex_unlock(&ps->pinst->lock); |
|
|
|
kfree(ps); |
|
} |
|
EXPORT_SYMBOL(padata_free_shell); |
|
|
|
void __init padata_init(void) |
|
{ |
|
unsigned int i, possible_cpus; |
|
#ifdef CONFIG_HOTPLUG_CPU |
|
int ret; |
|
|
|
ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online", |
|
padata_cpu_online, NULL); |
|
if (ret < 0) |
|
goto err; |
|
hp_online = ret; |
|
|
|
ret = cpuhp_setup_state_multi(CPUHP_PADATA_DEAD, "padata:dead", |
|
NULL, padata_cpu_dead); |
|
if (ret < 0) |
|
goto remove_online_state; |
|
#endif |
|
|
|
possible_cpus = num_possible_cpus(); |
|
padata_works = kmalloc_array(possible_cpus, sizeof(struct padata_work), |
|
GFP_KERNEL); |
|
if (!padata_works) |
|
goto remove_dead_state; |
|
|
|
for (i = 0; i < possible_cpus; ++i) |
|
list_add(&padata_works[i].pw_list, &padata_free_works); |
|
|
|
return; |
|
|
|
remove_dead_state: |
|
#ifdef CONFIG_HOTPLUG_CPU |
|
cpuhp_remove_multi_state(CPUHP_PADATA_DEAD); |
|
remove_online_state: |
|
cpuhp_remove_multi_state(hp_online); |
|
err: |
|
#endif |
|
pr_warn("padata: initialization failed\n"); |
|
}
|
|
|