mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 12:43:55 +08:00
b60fda6000
We currently have a race where if setup is really slow, we can be
calling io_wq_destroy() before we're done setting up. This will cause
the caller to get stuck waiting for the manager to set things up, but
the manager already exited.
Fix this by doing a sync setup of the manager. This also fixes the case
where if we failed creating workers, we'd also get stuck.
In practice this race window was really small, as we already wait for
the manager to start. Hence someone would have to call io_wq_destroy()
after the task has started, but before it started the first loop. The
reported test case forked tons of these, which is why it became an
issue.
Reported-by: syzbot+0f1cc17f85154f400465@syzkaller.appspotmail.com
Fixes: 771b53d033
("io-wq: small threadpool implementation for io_uring")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1086 lines
26 KiB
C
1086 lines
26 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Basic worker thread pool for io_uring
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*
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* Copyright (C) 2019 Jens Axboe
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*
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/sched/signal.h>
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#include <linux/mm.h>
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#include <linux/mmu_context.h>
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#include <linux/sched/mm.h>
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#include <linux/percpu.h>
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#include <linux/slab.h>
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#include <linux/kthread.h>
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#include <linux/rculist_nulls.h>
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#include "io-wq.h"
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#define WORKER_IDLE_TIMEOUT (5 * HZ)
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enum {
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IO_WORKER_F_UP = 1, /* up and active */
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IO_WORKER_F_RUNNING = 2, /* account as running */
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IO_WORKER_F_FREE = 4, /* worker on free list */
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IO_WORKER_F_EXITING = 8, /* worker exiting */
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IO_WORKER_F_FIXED = 16, /* static idle worker */
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IO_WORKER_F_BOUND = 32, /* is doing bounded work */
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};
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enum {
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IO_WQ_BIT_EXIT = 0, /* wq exiting */
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IO_WQ_BIT_CANCEL = 1, /* cancel work on list */
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IO_WQ_BIT_ERROR = 2, /* error on setup */
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};
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enum {
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IO_WQE_FLAG_STALLED = 1, /* stalled on hash */
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};
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/*
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* One for each thread in a wqe pool
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*/
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struct io_worker {
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refcount_t ref;
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unsigned flags;
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struct hlist_nulls_node nulls_node;
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struct list_head all_list;
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struct task_struct *task;
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wait_queue_head_t wait;
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struct io_wqe *wqe;
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struct io_wq_work *cur_work;
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spinlock_t lock;
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struct rcu_head rcu;
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struct mm_struct *mm;
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struct files_struct *restore_files;
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};
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#if BITS_PER_LONG == 64
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#define IO_WQ_HASH_ORDER 6
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#else
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#define IO_WQ_HASH_ORDER 5
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#endif
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struct io_wqe_acct {
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unsigned nr_workers;
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unsigned max_workers;
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atomic_t nr_running;
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};
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enum {
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IO_WQ_ACCT_BOUND,
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IO_WQ_ACCT_UNBOUND,
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};
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/*
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* Per-node worker thread pool
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*/
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struct io_wqe {
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struct {
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spinlock_t lock;
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struct list_head work_list;
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unsigned long hash_map;
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unsigned flags;
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} ____cacheline_aligned_in_smp;
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int node;
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struct io_wqe_acct acct[2];
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struct hlist_nulls_head free_list;
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struct hlist_nulls_head busy_list;
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struct list_head all_list;
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struct io_wq *wq;
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};
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/*
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* Per io_wq state
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*/
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struct io_wq {
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struct io_wqe **wqes;
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unsigned long state;
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unsigned nr_wqes;
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get_work_fn *get_work;
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put_work_fn *put_work;
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struct task_struct *manager;
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struct user_struct *user;
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struct mm_struct *mm;
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refcount_t refs;
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struct completion done;
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};
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static bool io_worker_get(struct io_worker *worker)
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{
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return refcount_inc_not_zero(&worker->ref);
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}
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static void io_worker_release(struct io_worker *worker)
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{
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if (refcount_dec_and_test(&worker->ref))
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wake_up_process(worker->task);
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}
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/*
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* Note: drops the wqe->lock if returning true! The caller must re-acquire
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* the lock in that case. Some callers need to restart handling if this
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* happens, so we can't just re-acquire the lock on behalf of the caller.
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*/
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static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
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{
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bool dropped_lock = false;
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if (current->files != worker->restore_files) {
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__acquire(&wqe->lock);
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spin_unlock_irq(&wqe->lock);
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dropped_lock = true;
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task_lock(current);
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current->files = worker->restore_files;
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task_unlock(current);
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}
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/*
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* If we have an active mm, we need to drop the wq lock before unusing
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* it. If we do, return true and let the caller retry the idle loop.
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*/
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if (worker->mm) {
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if (!dropped_lock) {
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__acquire(&wqe->lock);
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spin_unlock_irq(&wqe->lock);
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dropped_lock = true;
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}
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__set_current_state(TASK_RUNNING);
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set_fs(KERNEL_DS);
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unuse_mm(worker->mm);
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mmput(worker->mm);
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worker->mm = NULL;
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}
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return dropped_lock;
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}
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static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe,
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struct io_wq_work *work)
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{
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if (work->flags & IO_WQ_WORK_UNBOUND)
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return &wqe->acct[IO_WQ_ACCT_UNBOUND];
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return &wqe->acct[IO_WQ_ACCT_BOUND];
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}
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static inline struct io_wqe_acct *io_wqe_get_acct(struct io_wqe *wqe,
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struct io_worker *worker)
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{
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if (worker->flags & IO_WORKER_F_BOUND)
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return &wqe->acct[IO_WQ_ACCT_BOUND];
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return &wqe->acct[IO_WQ_ACCT_UNBOUND];
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}
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static void io_worker_exit(struct io_worker *worker)
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{
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struct io_wqe *wqe = worker->wqe;
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struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
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unsigned nr_workers;
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/*
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* If we're not at zero, someone else is holding a brief reference
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* to the worker. Wait for that to go away.
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*/
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set_current_state(TASK_INTERRUPTIBLE);
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if (!refcount_dec_and_test(&worker->ref))
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schedule();
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__set_current_state(TASK_RUNNING);
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preempt_disable();
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current->flags &= ~PF_IO_WORKER;
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if (worker->flags & IO_WORKER_F_RUNNING)
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atomic_dec(&acct->nr_running);
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if (!(worker->flags & IO_WORKER_F_BOUND))
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atomic_dec(&wqe->wq->user->processes);
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worker->flags = 0;
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preempt_enable();
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spin_lock_irq(&wqe->lock);
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hlist_nulls_del_rcu(&worker->nulls_node);
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list_del_rcu(&worker->all_list);
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if (__io_worker_unuse(wqe, worker)) {
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__release(&wqe->lock);
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spin_lock_irq(&wqe->lock);
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}
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acct->nr_workers--;
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nr_workers = wqe->acct[IO_WQ_ACCT_BOUND].nr_workers +
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wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers;
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spin_unlock_irq(&wqe->lock);
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/* all workers gone, wq exit can proceed */
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if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs))
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complete(&wqe->wq->done);
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kfree_rcu(worker, rcu);
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}
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static inline bool io_wqe_run_queue(struct io_wqe *wqe)
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__must_hold(wqe->lock)
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{
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if (!list_empty(&wqe->work_list) && !(wqe->flags & IO_WQE_FLAG_STALLED))
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return true;
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return false;
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}
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/*
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* Check head of free list for an available worker. If one isn't available,
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* caller must wake up the wq manager to create one.
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*/
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static bool io_wqe_activate_free_worker(struct io_wqe *wqe)
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__must_hold(RCU)
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{
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struct hlist_nulls_node *n;
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struct io_worker *worker;
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n = rcu_dereference(hlist_nulls_first_rcu(&wqe->free_list));
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if (is_a_nulls(n))
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return false;
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worker = hlist_nulls_entry(n, struct io_worker, nulls_node);
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if (io_worker_get(worker)) {
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wake_up(&worker->wait);
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io_worker_release(worker);
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return true;
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}
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return false;
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}
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/*
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* We need a worker. If we find a free one, we're good. If not, and we're
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* below the max number of workers, wake up the manager to create one.
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*/
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static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
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{
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bool ret;
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/*
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* Most likely an attempt to queue unbounded work on an io_wq that
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* wasn't setup with any unbounded workers.
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*/
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WARN_ON_ONCE(!acct->max_workers);
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rcu_read_lock();
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ret = io_wqe_activate_free_worker(wqe);
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rcu_read_unlock();
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if (!ret && acct->nr_workers < acct->max_workers)
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wake_up_process(wqe->wq->manager);
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}
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static void io_wqe_inc_running(struct io_wqe *wqe, struct io_worker *worker)
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{
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struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
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atomic_inc(&acct->nr_running);
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}
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static void io_wqe_dec_running(struct io_wqe *wqe, struct io_worker *worker)
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__must_hold(wqe->lock)
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{
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struct io_wqe_acct *acct = io_wqe_get_acct(wqe, worker);
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if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe))
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io_wqe_wake_worker(wqe, acct);
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}
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static void io_worker_start(struct io_wqe *wqe, struct io_worker *worker)
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{
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allow_kernel_signal(SIGINT);
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current->flags |= PF_IO_WORKER;
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worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
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worker->restore_files = current->files;
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io_wqe_inc_running(wqe, worker);
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}
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/*
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* Worker will start processing some work. Move it to the busy list, if
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* it's currently on the freelist
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*/
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static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
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struct io_wq_work *work)
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__must_hold(wqe->lock)
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{
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bool worker_bound, work_bound;
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if (worker->flags & IO_WORKER_F_FREE) {
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worker->flags &= ~IO_WORKER_F_FREE;
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hlist_nulls_del_init_rcu(&worker->nulls_node);
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hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->busy_list);
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}
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/*
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* If worker is moving from bound to unbound (or vice versa), then
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* ensure we update the running accounting.
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*/
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worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
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work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
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if (worker_bound != work_bound) {
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io_wqe_dec_running(wqe, worker);
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if (work_bound) {
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worker->flags |= IO_WORKER_F_BOUND;
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wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
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wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
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atomic_dec(&wqe->wq->user->processes);
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} else {
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worker->flags &= ~IO_WORKER_F_BOUND;
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wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
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wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
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atomic_inc(&wqe->wq->user->processes);
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}
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io_wqe_inc_running(wqe, worker);
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}
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}
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/*
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* No work, worker going to sleep. Move to freelist, and unuse mm if we
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* have one attached. Dropping the mm may potentially sleep, so we drop
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* the lock in that case and return success. Since the caller has to
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* retry the loop in that case (we changed task state), we don't regrab
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* the lock if we return success.
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*/
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static bool __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker)
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__must_hold(wqe->lock)
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{
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if (!(worker->flags & IO_WORKER_F_FREE)) {
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worker->flags |= IO_WORKER_F_FREE;
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hlist_nulls_del_init_rcu(&worker->nulls_node);
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hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
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}
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return __io_worker_unuse(wqe, worker);
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}
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static struct io_wq_work *io_get_next_work(struct io_wqe *wqe, unsigned *hash)
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__must_hold(wqe->lock)
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{
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struct io_wq_work *work;
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list_for_each_entry(work, &wqe->work_list, list) {
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/* not hashed, can run anytime */
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if (!(work->flags & IO_WQ_WORK_HASHED)) {
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list_del(&work->list);
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return work;
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}
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/* hashed, can run if not already running */
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*hash = work->flags >> IO_WQ_HASH_SHIFT;
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if (!(wqe->hash_map & BIT_ULL(*hash))) {
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wqe->hash_map |= BIT_ULL(*hash);
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list_del(&work->list);
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return work;
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}
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}
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return NULL;
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}
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static void io_worker_handle_work(struct io_worker *worker)
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__releases(wqe->lock)
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{
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struct io_wq_work *work, *old_work = NULL, *put_work = NULL;
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struct io_wqe *wqe = worker->wqe;
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struct io_wq *wq = wqe->wq;
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do {
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unsigned hash = -1U;
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/*
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* If we got some work, mark us as busy. If we didn't, but
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* the list isn't empty, it means we stalled on hashed work.
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* Mark us stalled so we don't keep looking for work when we
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* can't make progress, any work completion or insertion will
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* clear the stalled flag.
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*/
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work = io_get_next_work(wqe, &hash);
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if (work)
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__io_worker_busy(wqe, worker, work);
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else if (!list_empty(&wqe->work_list))
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wqe->flags |= IO_WQE_FLAG_STALLED;
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spin_unlock_irq(&wqe->lock);
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if (put_work && wq->put_work)
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wq->put_work(old_work);
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if (!work)
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break;
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next:
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/* flush any pending signals before assigning new work */
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if (signal_pending(current))
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flush_signals(current);
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spin_lock_irq(&worker->lock);
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worker->cur_work = work;
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spin_unlock_irq(&worker->lock);
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if ((work->flags & IO_WQ_WORK_NEEDS_FILES) &&
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current->files != work->files) {
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task_lock(current);
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current->files = work->files;
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task_unlock(current);
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}
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if ((work->flags & IO_WQ_WORK_NEEDS_USER) && !worker->mm &&
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wq->mm && mmget_not_zero(wq->mm)) {
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use_mm(wq->mm);
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set_fs(USER_DS);
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worker->mm = wq->mm;
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}
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if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
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work->flags |= IO_WQ_WORK_CANCEL;
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if (worker->mm)
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work->flags |= IO_WQ_WORK_HAS_MM;
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if (wq->get_work && !(work->flags & IO_WQ_WORK_INTERNAL)) {
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put_work = work;
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wq->get_work(work);
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}
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old_work = work;
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work->func(&work);
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spin_lock_irq(&worker->lock);
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worker->cur_work = NULL;
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spin_unlock_irq(&worker->lock);
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spin_lock_irq(&wqe->lock);
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if (hash != -1U) {
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wqe->hash_map &= ~BIT_ULL(hash);
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wqe->flags &= ~IO_WQE_FLAG_STALLED;
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}
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if (work && work != old_work) {
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spin_unlock_irq(&wqe->lock);
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if (put_work && wq->put_work) {
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wq->put_work(put_work);
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put_work = NULL;
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}
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/* dependent work not hashed */
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hash = -1U;
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goto next;
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}
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} while (1);
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}
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|
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static int io_wqe_worker(void *data)
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|
{
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struct io_worker *worker = data;
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struct io_wqe *wqe = worker->wqe;
|
|
struct io_wq *wq = wqe->wq;
|
|
DEFINE_WAIT(wait);
|
|
|
|
io_worker_start(wqe, worker);
|
|
|
|
while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
|
|
prepare_to_wait(&worker->wait, &wait, TASK_INTERRUPTIBLE);
|
|
|
|
spin_lock_irq(&wqe->lock);
|
|
if (io_wqe_run_queue(wqe)) {
|
|
__set_current_state(TASK_RUNNING);
|
|
io_worker_handle_work(worker);
|
|
continue;
|
|
}
|
|
/* drops the lock on success, retry */
|
|
if (__io_worker_idle(wqe, worker)) {
|
|
__release(&wqe->lock);
|
|
continue;
|
|
}
|
|
spin_unlock_irq(&wqe->lock);
|
|
if (signal_pending(current))
|
|
flush_signals(current);
|
|
if (schedule_timeout(WORKER_IDLE_TIMEOUT))
|
|
continue;
|
|
/* timed out, exit unless we're the fixed worker */
|
|
if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
|
|
!(worker->flags & IO_WORKER_F_FIXED))
|
|
break;
|
|
}
|
|
|
|
finish_wait(&worker->wait, &wait);
|
|
|
|
if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
|
|
spin_lock_irq(&wqe->lock);
|
|
if (!list_empty(&wqe->work_list))
|
|
io_worker_handle_work(worker);
|
|
else
|
|
spin_unlock_irq(&wqe->lock);
|
|
}
|
|
|
|
io_worker_exit(worker);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Called when a worker is scheduled in. Mark us as currently running.
|
|
*/
|
|
void io_wq_worker_running(struct task_struct *tsk)
|
|
{
|
|
struct io_worker *worker = kthread_data(tsk);
|
|
struct io_wqe *wqe = worker->wqe;
|
|
|
|
if (!(worker->flags & IO_WORKER_F_UP))
|
|
return;
|
|
if (worker->flags & IO_WORKER_F_RUNNING)
|
|
return;
|
|
worker->flags |= IO_WORKER_F_RUNNING;
|
|
io_wqe_inc_running(wqe, worker);
|
|
}
|
|
|
|
/*
|
|
* Called when worker is going to sleep. If there are no workers currently
|
|
* running and we have work pending, wake up a free one or have the manager
|
|
* set one up.
|
|
*/
|
|
void io_wq_worker_sleeping(struct task_struct *tsk)
|
|
{
|
|
struct io_worker *worker = kthread_data(tsk);
|
|
struct io_wqe *wqe = worker->wqe;
|
|
|
|
if (!(worker->flags & IO_WORKER_F_UP))
|
|
return;
|
|
if (!(worker->flags & IO_WORKER_F_RUNNING))
|
|
return;
|
|
|
|
worker->flags &= ~IO_WORKER_F_RUNNING;
|
|
|
|
spin_lock_irq(&wqe->lock);
|
|
io_wqe_dec_running(wqe, worker);
|
|
spin_unlock_irq(&wqe->lock);
|
|
}
|
|
|
|
static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
|
|
{
|
|
struct io_wqe_acct *acct =&wqe->acct[index];
|
|
struct io_worker *worker;
|
|
|
|
worker = kcalloc_node(1, sizeof(*worker), GFP_KERNEL, wqe->node);
|
|
if (!worker)
|
|
return false;
|
|
|
|
refcount_set(&worker->ref, 1);
|
|
worker->nulls_node.pprev = NULL;
|
|
init_waitqueue_head(&worker->wait);
|
|
worker->wqe = wqe;
|
|
spin_lock_init(&worker->lock);
|
|
|
|
worker->task = kthread_create_on_node(io_wqe_worker, worker, wqe->node,
|
|
"io_wqe_worker-%d/%d", index, wqe->node);
|
|
if (IS_ERR(worker->task)) {
|
|
kfree(worker);
|
|
return false;
|
|
}
|
|
|
|
spin_lock_irq(&wqe->lock);
|
|
hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
|
|
list_add_tail_rcu(&worker->all_list, &wqe->all_list);
|
|
worker->flags |= IO_WORKER_F_FREE;
|
|
if (index == IO_WQ_ACCT_BOUND)
|
|
worker->flags |= IO_WORKER_F_BOUND;
|
|
if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
|
|
worker->flags |= IO_WORKER_F_FIXED;
|
|
acct->nr_workers++;
|
|
spin_unlock_irq(&wqe->lock);
|
|
|
|
if (index == IO_WQ_ACCT_UNBOUND)
|
|
atomic_inc(&wq->user->processes);
|
|
|
|
wake_up_process(worker->task);
|
|
return true;
|
|
}
|
|
|
|
static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index)
|
|
__must_hold(wqe->lock)
|
|
{
|
|
struct io_wqe_acct *acct = &wqe->acct[index];
|
|
|
|
/* if we have available workers or no work, no need */
|
|
if (!hlist_nulls_empty(&wqe->free_list) || !io_wqe_run_queue(wqe))
|
|
return false;
|
|
return acct->nr_workers < acct->max_workers;
|
|
}
|
|
|
|
/*
|
|
* Manager thread. Tasked with creating new workers, if we need them.
|
|
*/
|
|
static int io_wq_manager(void *data)
|
|
{
|
|
struct io_wq *wq = data;
|
|
int i;
|
|
|
|
/* create fixed workers */
|
|
refcount_set(&wq->refs, wq->nr_wqes);
|
|
for (i = 0; i < wq->nr_wqes; i++) {
|
|
if (create_io_worker(wq, wq->wqes[i], IO_WQ_ACCT_BOUND))
|
|
continue;
|
|
goto err;
|
|
}
|
|
|
|
complete(&wq->done);
|
|
|
|
while (!kthread_should_stop()) {
|
|
for (i = 0; i < wq->nr_wqes; i++) {
|
|
struct io_wqe *wqe = wq->wqes[i];
|
|
bool fork_worker[2] = { false, false };
|
|
|
|
spin_lock_irq(&wqe->lock);
|
|
if (io_wqe_need_worker(wqe, IO_WQ_ACCT_BOUND))
|
|
fork_worker[IO_WQ_ACCT_BOUND] = true;
|
|
if (io_wqe_need_worker(wqe, IO_WQ_ACCT_UNBOUND))
|
|
fork_worker[IO_WQ_ACCT_UNBOUND] = true;
|
|
spin_unlock_irq(&wqe->lock);
|
|
if (fork_worker[IO_WQ_ACCT_BOUND])
|
|
create_io_worker(wq, wqe, IO_WQ_ACCT_BOUND);
|
|
if (fork_worker[IO_WQ_ACCT_UNBOUND])
|
|
create_io_worker(wq, wqe, IO_WQ_ACCT_UNBOUND);
|
|
}
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
schedule_timeout(HZ);
|
|
}
|
|
|
|
return 0;
|
|
err:
|
|
set_bit(IO_WQ_BIT_ERROR, &wq->state);
|
|
set_bit(IO_WQ_BIT_EXIT, &wq->state);
|
|
if (refcount_sub_and_test(wq->nr_wqes - i, &wq->refs))
|
|
complete(&wq->done);
|
|
return 0;
|
|
}
|
|
|
|
static bool io_wq_can_queue(struct io_wqe *wqe, struct io_wqe_acct *acct,
|
|
struct io_wq_work *work)
|
|
{
|
|
bool free_worker;
|
|
|
|
if (!(work->flags & IO_WQ_WORK_UNBOUND))
|
|
return true;
|
|
if (atomic_read(&acct->nr_running))
|
|
return true;
|
|
|
|
rcu_read_lock();
|
|
free_worker = !hlist_nulls_empty(&wqe->free_list);
|
|
rcu_read_unlock();
|
|
if (free_worker)
|
|
return true;
|
|
|
|
if (atomic_read(&wqe->wq->user->processes) >= acct->max_workers &&
|
|
!(capable(CAP_SYS_RESOURCE) || capable(CAP_SYS_ADMIN)))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
|
|
{
|
|
struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* Do early check to see if we need a new unbound worker, and if we do,
|
|
* if we're allowed to do so. This isn't 100% accurate as there's a
|
|
* gap between this check and incrementing the value, but that's OK.
|
|
* It's close enough to not be an issue, fork() has the same delay.
|
|
*/
|
|
if (unlikely(!io_wq_can_queue(wqe, acct, work))) {
|
|
work->flags |= IO_WQ_WORK_CANCEL;
|
|
work->func(&work);
|
|
return;
|
|
}
|
|
|
|
spin_lock_irqsave(&wqe->lock, flags);
|
|
list_add_tail(&work->list, &wqe->work_list);
|
|
wqe->flags &= ~IO_WQE_FLAG_STALLED;
|
|
spin_unlock_irqrestore(&wqe->lock, flags);
|
|
|
|
if (!atomic_read(&acct->nr_running))
|
|
io_wqe_wake_worker(wqe, acct);
|
|
}
|
|
|
|
void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
|
|
{
|
|
struct io_wqe *wqe = wq->wqes[numa_node_id()];
|
|
|
|
io_wqe_enqueue(wqe, work);
|
|
}
|
|
|
|
/*
|
|
* Enqueue work, hashed by some key. Work items that hash to the same value
|
|
* will not be done in parallel. Used to limit concurrent writes, generally
|
|
* hashed by inode.
|
|
*/
|
|
void io_wq_enqueue_hashed(struct io_wq *wq, struct io_wq_work *work, void *val)
|
|
{
|
|
struct io_wqe *wqe = wq->wqes[numa_node_id()];
|
|
unsigned bit;
|
|
|
|
|
|
bit = hash_ptr(val, IO_WQ_HASH_ORDER);
|
|
work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
|
|
io_wqe_enqueue(wqe, work);
|
|
}
|
|
|
|
static bool io_wqe_worker_send_sig(struct io_worker *worker, void *data)
|
|
{
|
|
send_sig(SIGINT, worker->task, 1);
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Iterate the passed in list and call the specific function for each
|
|
* worker that isn't exiting
|
|
*/
|
|
static bool io_wq_for_each_worker(struct io_wqe *wqe,
|
|
bool (*func)(struct io_worker *, void *),
|
|
void *data)
|
|
{
|
|
struct io_worker *worker;
|
|
bool ret = false;
|
|
|
|
list_for_each_entry_rcu(worker, &wqe->all_list, all_list) {
|
|
if (io_worker_get(worker)) {
|
|
ret = func(worker, data);
|
|
io_worker_release(worker);
|
|
if (ret)
|
|
break;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
void io_wq_cancel_all(struct io_wq *wq)
|
|
{
|
|
int i;
|
|
|
|
set_bit(IO_WQ_BIT_CANCEL, &wq->state);
|
|
|
|
/*
|
|
* Browse both lists, as there's a gap between handing work off
|
|
* to a worker and the worker putting itself on the busy_list
|
|
*/
|
|
rcu_read_lock();
|
|
for (i = 0; i < wq->nr_wqes; i++) {
|
|
struct io_wqe *wqe = wq->wqes[i];
|
|
|
|
io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
struct io_cb_cancel_data {
|
|
struct io_wqe *wqe;
|
|
work_cancel_fn *cancel;
|
|
void *caller_data;
|
|
};
|
|
|
|
static bool io_work_cancel(struct io_worker *worker, void *cancel_data)
|
|
{
|
|
struct io_cb_cancel_data *data = cancel_data;
|
|
unsigned long flags;
|
|
bool ret = false;
|
|
|
|
/*
|
|
* Hold the lock to avoid ->cur_work going out of scope, caller
|
|
* may dereference the passed in work.
|
|
*/
|
|
spin_lock_irqsave(&worker->lock, flags);
|
|
if (worker->cur_work &&
|
|
data->cancel(worker->cur_work, data->caller_data)) {
|
|
send_sig(SIGINT, worker->task, 1);
|
|
ret = true;
|
|
}
|
|
spin_unlock_irqrestore(&worker->lock, flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static enum io_wq_cancel io_wqe_cancel_cb_work(struct io_wqe *wqe,
|
|
work_cancel_fn *cancel,
|
|
void *cancel_data)
|
|
{
|
|
struct io_cb_cancel_data data = {
|
|
.wqe = wqe,
|
|
.cancel = cancel,
|
|
.caller_data = cancel_data,
|
|
};
|
|
struct io_wq_work *work;
|
|
unsigned long flags;
|
|
bool found = false;
|
|
|
|
spin_lock_irqsave(&wqe->lock, flags);
|
|
list_for_each_entry(work, &wqe->work_list, list) {
|
|
if (cancel(work, cancel_data)) {
|
|
list_del(&work->list);
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&wqe->lock, flags);
|
|
|
|
if (found) {
|
|
work->flags |= IO_WQ_WORK_CANCEL;
|
|
work->func(&work);
|
|
return IO_WQ_CANCEL_OK;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
found = io_wq_for_each_worker(wqe, io_work_cancel, &data);
|
|
rcu_read_unlock();
|
|
return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
|
|
}
|
|
|
|
enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
|
|
void *data)
|
|
{
|
|
enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
|
|
int i;
|
|
|
|
for (i = 0; i < wq->nr_wqes; i++) {
|
|
struct io_wqe *wqe = wq->wqes[i];
|
|
|
|
ret = io_wqe_cancel_cb_work(wqe, cancel, data);
|
|
if (ret != IO_WQ_CANCEL_NOTFOUND)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
|
|
{
|
|
struct io_wq_work *work = data;
|
|
unsigned long flags;
|
|
bool ret = false;
|
|
|
|
if (worker->cur_work != work)
|
|
return false;
|
|
|
|
spin_lock_irqsave(&worker->lock, flags);
|
|
if (worker->cur_work == work) {
|
|
send_sig(SIGINT, worker->task, 1);
|
|
ret = true;
|
|
}
|
|
spin_unlock_irqrestore(&worker->lock, flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static enum io_wq_cancel io_wqe_cancel_work(struct io_wqe *wqe,
|
|
struct io_wq_work *cwork)
|
|
{
|
|
struct io_wq_work *work;
|
|
unsigned long flags;
|
|
bool found = false;
|
|
|
|
cwork->flags |= IO_WQ_WORK_CANCEL;
|
|
|
|
/*
|
|
* First check pending list, if we're lucky we can just remove it
|
|
* from there. CANCEL_OK means that the work is returned as-new,
|
|
* no completion will be posted for it.
|
|
*/
|
|
spin_lock_irqsave(&wqe->lock, flags);
|
|
list_for_each_entry(work, &wqe->work_list, list) {
|
|
if (work == cwork) {
|
|
list_del(&work->list);
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&wqe->lock, flags);
|
|
|
|
if (found) {
|
|
work->flags |= IO_WQ_WORK_CANCEL;
|
|
work->func(&work);
|
|
return IO_WQ_CANCEL_OK;
|
|
}
|
|
|
|
/*
|
|
* Now check if a free (going busy) or busy worker has the work
|
|
* currently running. If we find it there, we'll return CANCEL_RUNNING
|
|
* as an indication that we attempte to signal cancellation. The
|
|
* completion will run normally in this case.
|
|
*/
|
|
rcu_read_lock();
|
|
found = io_wq_for_each_worker(wqe, io_wq_worker_cancel, cwork);
|
|
rcu_read_unlock();
|
|
return found ? IO_WQ_CANCEL_RUNNING : IO_WQ_CANCEL_NOTFOUND;
|
|
}
|
|
|
|
enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork)
|
|
{
|
|
enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
|
|
int i;
|
|
|
|
for (i = 0; i < wq->nr_wqes; i++) {
|
|
struct io_wqe *wqe = wq->wqes[i];
|
|
|
|
ret = io_wqe_cancel_work(wqe, cwork);
|
|
if (ret != IO_WQ_CANCEL_NOTFOUND)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
struct io_wq_flush_data {
|
|
struct io_wq_work work;
|
|
struct completion done;
|
|
};
|
|
|
|
static void io_wq_flush_func(struct io_wq_work **workptr)
|
|
{
|
|
struct io_wq_work *work = *workptr;
|
|
struct io_wq_flush_data *data;
|
|
|
|
data = container_of(work, struct io_wq_flush_data, work);
|
|
complete(&data->done);
|
|
}
|
|
|
|
/*
|
|
* Doesn't wait for previously queued work to finish. When this completes,
|
|
* it just means that previously queued work was started.
|
|
*/
|
|
void io_wq_flush(struct io_wq *wq)
|
|
{
|
|
struct io_wq_flush_data data;
|
|
int i;
|
|
|
|
for (i = 0; i < wq->nr_wqes; i++) {
|
|
struct io_wqe *wqe = wq->wqes[i];
|
|
|
|
init_completion(&data.done);
|
|
INIT_IO_WORK(&data.work, io_wq_flush_func);
|
|
data.work.flags |= IO_WQ_WORK_INTERNAL;
|
|
io_wqe_enqueue(wqe, &data.work);
|
|
wait_for_completion(&data.done);
|
|
}
|
|
}
|
|
|
|
struct io_wq *io_wq_create(unsigned bounded, struct mm_struct *mm,
|
|
struct user_struct *user, get_work_fn *get_work,
|
|
put_work_fn *put_work)
|
|
{
|
|
int ret = -ENOMEM, i, node;
|
|
struct io_wq *wq;
|
|
|
|
wq = kcalloc(1, sizeof(*wq), GFP_KERNEL);
|
|
if (!wq)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
wq->nr_wqes = num_online_nodes();
|
|
wq->wqes = kcalloc(wq->nr_wqes, sizeof(struct io_wqe *), GFP_KERNEL);
|
|
if (!wq->wqes) {
|
|
kfree(wq);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
wq->get_work = get_work;
|
|
wq->put_work = put_work;
|
|
|
|
/* caller must already hold a reference to this */
|
|
wq->user = user;
|
|
|
|
i = 0;
|
|
for_each_online_node(node) {
|
|
struct io_wqe *wqe;
|
|
|
|
wqe = kcalloc_node(1, sizeof(struct io_wqe), GFP_KERNEL, node);
|
|
if (!wqe)
|
|
break;
|
|
wq->wqes[i] = wqe;
|
|
wqe->node = node;
|
|
wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
|
|
atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0);
|
|
if (user) {
|
|
wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
|
|
task_rlimit(current, RLIMIT_NPROC);
|
|
}
|
|
atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0);
|
|
wqe->node = node;
|
|
wqe->wq = wq;
|
|
spin_lock_init(&wqe->lock);
|
|
INIT_LIST_HEAD(&wqe->work_list);
|
|
INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
|
|
INIT_HLIST_NULLS_HEAD(&wqe->busy_list, 1);
|
|
INIT_LIST_HEAD(&wqe->all_list);
|
|
|
|
i++;
|
|
}
|
|
|
|
init_completion(&wq->done);
|
|
|
|
if (i != wq->nr_wqes)
|
|
goto err;
|
|
|
|
/* caller must have already done mmgrab() on this mm */
|
|
wq->mm = mm;
|
|
|
|
wq->manager = kthread_create(io_wq_manager, wq, "io_wq_manager");
|
|
if (!IS_ERR(wq->manager)) {
|
|
wake_up_process(wq->manager);
|
|
wait_for_completion(&wq->done);
|
|
if (test_bit(IO_WQ_BIT_ERROR, &wq->state)) {
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
reinit_completion(&wq->done);
|
|
return wq;
|
|
}
|
|
|
|
ret = PTR_ERR(wq->manager);
|
|
complete(&wq->done);
|
|
err:
|
|
for (i = 0; i < wq->nr_wqes; i++)
|
|
kfree(wq->wqes[i]);
|
|
kfree(wq->wqes);
|
|
kfree(wq);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
static bool io_wq_worker_wake(struct io_worker *worker, void *data)
|
|
{
|
|
wake_up_process(worker->task);
|
|
return false;
|
|
}
|
|
|
|
void io_wq_destroy(struct io_wq *wq)
|
|
{
|
|
int i;
|
|
|
|
set_bit(IO_WQ_BIT_EXIT, &wq->state);
|
|
if (wq->manager)
|
|
kthread_stop(wq->manager);
|
|
|
|
rcu_read_lock();
|
|
for (i = 0; i < wq->nr_wqes; i++) {
|
|
struct io_wqe *wqe = wq->wqes[i];
|
|
|
|
if (!wqe)
|
|
continue;
|
|
io_wq_for_each_worker(wqe, io_wq_worker_wake, NULL);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
wait_for_completion(&wq->done);
|
|
|
|
for (i = 0; i < wq->nr_wqes; i++)
|
|
kfree(wq->wqes[i]);
|
|
kfree(wq->wqes);
|
|
kfree(wq);
|
|
}
|