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-rw-r--r--kernel/padata.c1150
1 files changed, 1150 insertions, 0 deletions
diff --git a/kernel/padata.c b/kernel/padata.c
new file mode 100644
index 000000000..7bef7dae3
--- /dev/null
+++ b/kernel/padata.c
@@ -0,0 +1,1150 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * padata.c - generic interface to process data streams in parallel
+ *
+ * See Documentation/core-api/padata.rst for more information.
+ *
+ * Copyright (C) 2008, 2009 secunet Security Networks AG
+ * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
+ *
+ * Copyright (c) 2020 Oracle and/or its affiliates.
+ * Author: Daniel Jordan <daniel.m.jordan@oracle.com>
+ */
+
+#include <linux/completion.h>
+#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 PADATA_WORK_ONSTACK 1 /* Work's memory is on stack */
+
+struct padata_work {
+ struct work_struct pw_work;
+ struct list_head pw_list; /* padata_free_works linkage */
+ void *pw_data;
+};
+
+static DEFINE_SPINLOCK(padata_works_lock);
+static struct padata_work *padata_works;
+static LIST_HEAD(padata_free_works);
+
+struct padata_mt_job_state {
+ spinlock_t lock;
+ struct completion completion;
+ struct padata_mt_job *job;
+ int nworks;
+ int nworks_fini;
+ unsigned long chunk_size;
+};
+
+static void padata_free_pd(struct parallel_data *pd);
+static void __init padata_mt_helper(struct work_struct *work);
+
+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 struct padata_work *padata_work_alloc(void)
+{
+ struct padata_work *pw;
+
+ lockdep_assert_held(&padata_works_lock);
+
+ if (list_empty(&padata_free_works))
+ return NULL; /* No more work items allowed to be queued. */
+
+ pw = list_first_entry(&padata_free_works, struct padata_work, pw_list);
+ list_del(&pw->pw_list);
+ return pw;
+}
+
+static void padata_work_init(struct padata_work *pw, work_func_t work_fn,
+ void *data, int flags)
+{
+ if (flags & PADATA_WORK_ONSTACK)
+ INIT_WORK_ONSTACK(&pw->pw_work, work_fn);
+ else
+ INIT_WORK(&pw->pw_work, work_fn);
+ pw->pw_data = data;
+}
+
+static int __init padata_work_alloc_mt(int nworks, void *data,
+ struct list_head *head)
+{
+ int i;
+
+ spin_lock(&padata_works_lock);
+ /* Start at 1 because the current task participates in the job. */
+ for (i = 1; i < nworks; ++i) {
+ struct padata_work *pw = padata_work_alloc();
+
+ if (!pw)
+ break;
+ padata_work_init(pw, padata_mt_helper, data, 0);
+ list_add(&pw->pw_list, head);
+ }
+ spin_unlock(&padata_works_lock);
+
+ return i;
+}
+
+static void padata_work_free(struct padata_work *pw)
+{
+ lockdep_assert_held(&padata_works_lock);
+ list_add(&pw->pw_list, &padata_free_works);
+}
+
+static void __init padata_works_free(struct list_head *works)
+{
+ struct padata_work *cur, *next;
+
+ if (list_empty(works))
+ return;
+
+ spin_lock(&padata_works_lock);
+ list_for_each_entry_safe(cur, next, works, pw_list) {
+ list_del(&cur->pw_list);
+ padata_work_free(cur);
+ }
+ spin_unlock(&padata_works_lock);
+}
+
+static void padata_parallel_worker(struct work_struct *parallel_work)
+{
+ struct padata_work *pw = container_of(parallel_work, struct padata_work,
+ pw_work);
+ struct padata_priv *padata = pw->pw_data;
+
+ local_bh_disable();
+ padata->parallel(padata);
+ spin_lock(&padata_works_lock);
+ padata_work_free(pw);
+ spin_unlock(&padata_works_lock);
+ local_bh_enable();
+}
+
+/**
+ * padata_do_parallel - padata parallelization function
+ *
+ * @ps: padatashell
+ * @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.
+ *
+ * Return: 0 on success or else negative error code.
+ */
+int padata_do_parallel(struct padata_shell *ps,
+ struct padata_priv *padata, int *cb_cpu)
+{
+ struct padata_instance *pinst = ps->pinst;
+ int i, cpu, cpu_index, err;
+ struct parallel_data *pd;
+ struct padata_work *pw;
+
+ rcu_read_lock_bh();
+
+ pd = rcu_dereference_bh(ps->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_empty(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;
+
+ refcount_inc(&pd->refcnt);
+ padata->pd = pd;
+ padata->cb_cpu = *cb_cpu;
+
+ spin_lock(&padata_works_lock);
+ padata->seq_nr = ++pd->seq_nr;
+ pw = padata_work_alloc();
+ spin_unlock(&padata_works_lock);
+
+ if (!pw) {
+ /* Maximum works limit exceeded, run in the current task. */
+ padata->parallel(padata);
+ }
+
+ rcu_read_unlock_bh();
+
+ if (pw) {
+ padata_work_init(pw, padata_parallel_worker, padata, 0);
+ queue_work(pinst->parallel_wq, &pw->pw_work);
+ }
+
+ return 0;
+out:
+ rcu_read_unlock_bh();
+
+ return err;
+}
+EXPORT_SYMBOL(padata_do_parallel);
+
+/*
+ * padata_find_next - Find the next object that needs serialization.
+ *
+ * Return:
+ * * 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_priv *padata;
+ struct padata_list *reorder;
+ int cpu = pd->cpu;
+
+ reorder = per_cpu_ptr(pd->reorder_list, cpu);
+
+ 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);
+ ++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)
+{
+ struct padata_instance *pinst = pd->ps->pinst;
+ int cb_cpu;
+ struct padata_priv *padata;
+ struct padata_serial_queue *squeue;
+ struct padata_list *reorder;
+
+ /*
+ * 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 in padata_do_serial.
+ */
+ smp_mb();
+
+ reorder = per_cpu_ptr(pd->reorder_list, pd->cpu);
+ if (!list_empty(&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);
+ int cnt;
+
+ 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);
+
+ cnt = 0;
+
+ 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);
+ cnt++;
+ }
+ local_bh_enable();
+
+ if (refcount_sub_and_test(cnt, &pd->refcnt))
+ padata_free_pd(pd);
+}
+
+/**
+ * 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;
+ int hashed_cpu = padata_cpu_hash(pd, padata->seq_nr);
+ struct padata_list *reorder = per_cpu_ptr(pd->reorder_list, hashed_cpu);
+ struct padata_priv *cur;
+ struct list_head *pos;
+
+ spin_lock(&reorder->lock);
+ /* Sort in ascending order of sequence number. */
+ list_for_each_prev(pos, &reorder->list) {
+ cur = list_entry(pos, struct padata_priv, list);
+ if (cur->seq_nr < padata->seq_nr)
+ break;
+ }
+ list_add(&padata->list, pos);
+ spin_unlock(&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();
+
+ padata_reorder(pd);
+}
+EXPORT_SYMBOL(padata_do_serial);
+
+static int padata_setup_cpumasks(struct padata_instance *pinst)
+{
+ struct workqueue_attrs *attrs;
+ int err;
+
+ attrs = alloc_workqueue_attrs();
+ if (!attrs)
+ return -ENOMEM;
+
+ /* Restrict parallel_wq workers to pd->cpumask.pcpu. */
+ cpumask_copy(attrs->cpumask, pinst->cpumask.pcpu);
+ err = apply_workqueue_attrs(pinst->parallel_wq, attrs);
+ free_workqueue_attrs(attrs);
+
+ return err;
+}
+
+static void __init padata_mt_helper(struct work_struct *w)
+{
+ struct padata_work *pw = container_of(w, struct padata_work, pw_work);
+ struct padata_mt_job_state *ps = pw->pw_data;
+ struct padata_mt_job *job = ps->job;
+ bool done;
+
+ spin_lock(&ps->lock);
+
+ while (job->size > 0) {
+ unsigned long start, size, end;
+
+ start = job->start;
+ /* So end is chunk size aligned if enough work remains. */
+ size = roundup(start + 1, ps->chunk_size) - start;
+ size = min(size, job->size);
+ end = start + size;
+
+ job->start = end;
+ job->size -= size;
+
+ spin_unlock(&ps->lock);
+ job->thread_fn(start, end, job->fn_arg);
+ spin_lock(&ps->lock);
+ }
+
+ ++ps->nworks_fini;
+ done = (ps->nworks_fini == ps->nworks);
+ spin_unlock(&ps->lock);
+
+ if (done)
+ complete(&ps->completion);
+}
+
+/**
+ * padata_do_multithreaded - run a multithreaded job
+ * @job: Description of the job.
+ *
+ * See the definition of struct padata_mt_job for more details.
+ */
+void __init padata_do_multithreaded(struct padata_mt_job *job)
+{
+ /* In case threads finish at different times. */
+ static const unsigned long load_balance_factor = 4;
+ struct padata_work my_work, *pw;
+ struct padata_mt_job_state ps;
+ LIST_HEAD(works);
+ int nworks;
+
+ if (job->size == 0)
+ return;
+
+ /* 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) {
+ /* Single thread, no coordination needed, cut to the chase. */
+ job->thread_fn(job->start, job->start + job->size, job->fn_arg);
+ return;
+ }
+
+ spin_lock_init(&ps.lock);
+ init_completion(&ps.completion);
+ ps.job = job;
+ ps.nworks = padata_work_alloc_mt(nworks, &ps, &works);
+ ps.nworks_fini = 0;
+
+ /*
+ * 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);
+
+ list_for_each_entry(pw, &works, pw_list)
+ queue_work(system_unbound_wq, &pw->pw_work);
+
+ /* Use the current thread, which saves starting a workqueue worker. */
+ padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK);
+ 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);
+ padata_works_free(&works);
+}
+
+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 per-CPU reorder lists */
+static void padata_init_reorder_list(struct parallel_data *pd)
+{
+ int cpu;
+ struct padata_list *list;
+
+ for_each_cpu(cpu, pd->cpumask.pcpu) {
+ list = per_cpu_ptr(pd->reorder_list, cpu);
+ __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,
+ &parallel_cpumask_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(padata_default);
+
+static ssize_t padata_sysfs_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct padata_instance *pinst;
+ struct padata_sysfs_entry *pentry;
+ ssize_t ret = -EIO;
+
+ pinst = kobj2pinst(kobj);
+ pentry = attr2pentry(attr);
+ if (pentry->show)
+ ret = pentry->show(pinst, attr, buf);
+
+ return ret;
+}
+
+static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
+ const char *buf, size_t count)
+{
+ struct padata_instance *pinst;
+ struct padata_sysfs_entry *pentry;
+ ssize_t ret = -EIO;
+
+ pinst = kobj2pinst(kobj);
+ pentry = attr2pentry(attr);
+ if (pentry->show)
+ ret = pentry->store(pinst, attr, buf, count);
+
+ return ret;
+}
+
+static const struct sysfs_ops padata_sysfs_ops = {
+ .show = padata_sysfs_show,
+ .store = padata_sysfs_store,
+};
+
+static struct kobj_type padata_attr_type = {
+ .sysfs_ops = &padata_sysfs_ops,
+ .default_groups = padata_default_groups,
+ .release = padata_sysfs_release,
+};
+
+/**
+ * padata_alloc - allocate and initialize a padata instance
+ * @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)
+{
+ struct parallel_data *pd;
+
+ if (!ps)
+ return;
+
+ mutex_lock(&ps->pinst->lock);
+ list_del(&ps->list);
+ pd = rcu_dereference_protected(ps->pd, 1);
+ if (refcount_dec_and_test(&pd->refcnt))
+ padata_free_pd(pd);
+ 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");
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-04 11:17:50 +0000