// SPDX-License-Identifier: GPL-2.0 #include <linux/kernel.h> #include <linux/errno.h> #include <linux/file.h> #include <linux/io_uring.h> #include <trace/events/io_uring.h> #include <uapi/linux/io_uring.h> #include "io_uring.h" #include "refs.h" #include "cancel.h" #include "timeout.h" struct io_timeout { struct file *file; u32 off; u32 target_seq; u32 repeats; struct list_head list; /* head of the link, used by linked timeouts only */ struct io_kiocb *head; /* for linked completions */ struct io_kiocb *prev; }; struct io_timeout_rem { struct file *file; u64 addr; /* timeout update */ struct timespec64 ts; u32 flags; bool ltimeout; }; static inline bool io_is_timeout_noseq(struct io_kiocb *req) { struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_timeout_data *data = req->async_data; return !timeout->off || data->flags & IORING_TIMEOUT_MULTISHOT; } static inline void io_put_req(struct io_kiocb *req) { if (req_ref_put_and_test(req)) { io_queue_next(req); io_free_req(req); } } static inline bool io_timeout_finish(struct io_timeout *timeout, struct io_timeout_data *data) { if (!(data->flags & IORING_TIMEOUT_MULTISHOT)) return true; if (!timeout->off || (timeout->repeats && --timeout->repeats)) return false; return true; } static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer); static void io_timeout_complete(struct io_kiocb *req, struct io_tw_state *ts) { struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_timeout_data *data = req->async_data; struct io_ring_ctx *ctx = req->ctx; if (!io_timeout_finish(timeout, data)) { if (io_req_post_cqe(req, -ETIME, IORING_CQE_F_MORE)) { /* re-arm timer */ spin_lock_irq(&ctx->timeout_lock); list_add(&timeout->list, ctx->timeout_list.prev); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); spin_unlock_irq(&ctx->timeout_lock); return; } } io_req_task_complete(req, ts); } static bool io_kill_timeout(struct io_kiocb *req, int status) __must_hold(&req->ctx->timeout_lock) { struct io_timeout_data *io = req->async_data; if (hrtimer_try_to_cancel(&io->timer) != -1) { struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); if (status) req_set_fail(req); atomic_set(&req->ctx->cq_timeouts, atomic_read(&req->ctx->cq_timeouts) + 1); list_del_init(&timeout->list); io_req_queue_tw_complete(req, status); return true; } return false; } __cold void io_flush_timeouts(struct io_ring_ctx *ctx) { u32 seq; struct io_timeout *timeout, *tmp; spin_lock_irq(&ctx->timeout_lock); seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) { struct io_kiocb *req = cmd_to_io_kiocb(timeout); u32 events_needed, events_got; if (io_is_timeout_noseq(req)) break; /* * Since seq can easily wrap around over time, subtract * the last seq at which timeouts were flushed before comparing. * Assuming not more than 2^31-1 events have happened since, * these subtractions won't have wrapped, so we can check if * target is in [last_seq, current_seq] by comparing the two. */ events_needed = timeout->target_seq - ctx->cq_last_tm_flush; events_got = seq - ctx->cq_last_tm_flush; if (events_got < events_needed) break; io_kill_timeout(req, 0); } ctx->cq_last_tm_flush = seq; spin_unlock_irq(&ctx->timeout_lock); } static void io_req_tw_fail_links(struct io_kiocb *link, struct io_tw_state *ts) { io_tw_lock(link->ctx, ts); while (link) { struct io_kiocb *nxt = link->link; long res = -ECANCELED; if (link->flags & REQ_F_FAIL) res = link->cqe.res; link->link = NULL; io_req_set_res(link, res, 0); io_req_task_complete(link, ts); link = nxt; } } static void io_fail_links(struct io_kiocb *req) __must_hold(&req->ctx->completion_lock) { struct io_kiocb *link = req->link; bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES; if (!link) return; while (link) { if (ignore_cqes) link->flags |= REQ_F_CQE_SKIP; else link->flags &= ~REQ_F_CQE_SKIP; trace_io_uring_fail_link(req, link); link = link->link; } link = req->link; link->io_task_work.func = io_req_tw_fail_links; io_req_task_work_add(link); req->link = NULL; } static inline void io_remove_next_linked(struct io_kiocb *req) { struct io_kiocb *nxt = req->link; req->link = nxt->link; nxt->link = NULL; } void io_disarm_next(struct io_kiocb *req) __must_hold(&req->ctx->completion_lock) { struct io_kiocb *link = NULL; if (req->flags & REQ_F_ARM_LTIMEOUT) { link = req->link; req->flags &= ~REQ_F_ARM_LTIMEOUT; if (link && link->opcode == IORING_OP_LINK_TIMEOUT) { io_remove_next_linked(req); io_req_queue_tw_complete(link, -ECANCELED); } } else if (req->flags & REQ_F_LINK_TIMEOUT) { struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->timeout_lock); link = io_disarm_linked_timeout(req); spin_unlock_irq(&ctx->timeout_lock); if (link) io_req_queue_tw_complete(link, -ECANCELED); } if (unlikely((req->flags & REQ_F_FAIL) && !(req->flags & REQ_F_HARDLINK))) io_fail_links(req); } struct io_kiocb *__io_disarm_linked_timeout(struct io_kiocb *req, struct io_kiocb *link) __must_hold(&req->ctx->completion_lock) __must_hold(&req->ctx->timeout_lock) { struct io_timeout_data *io = link->async_data; struct io_timeout *timeout = io_kiocb_to_cmd(link, struct io_timeout); io_remove_next_linked(req); timeout->head = NULL; if (hrtimer_try_to_cancel(&io->timer) != -1) { list_del(&timeout->list); return link; } return NULL; } static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *req = data->req; struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->timeout_lock, flags); list_del_init(&timeout->list); atomic_set(&req->ctx->cq_timeouts, atomic_read(&req->ctx->cq_timeouts) + 1); spin_unlock_irqrestore(&ctx->timeout_lock, flags); if (!(data->flags & IORING_TIMEOUT_ETIME_SUCCESS)) req_set_fail(req); io_req_set_res(req, -ETIME, 0); req->io_task_work.func = io_timeout_complete; io_req_task_work_add(req); return HRTIMER_NORESTART; } static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx, struct io_cancel_data *cd) __must_hold(&ctx->timeout_lock) { struct io_timeout *timeout; struct io_timeout_data *io; struct io_kiocb *req = NULL; list_for_each_entry(timeout, &ctx->timeout_list, list) { struct io_kiocb *tmp = cmd_to_io_kiocb(timeout); if (io_cancel_req_match(tmp, cd)) { req = tmp; break; } } if (!req) return ERR_PTR(-ENOENT); io = req->async_data; if (hrtimer_try_to_cancel(&io->timer) == -1) return ERR_PTR(-EALREADY); timeout = io_kiocb_to_cmd(req, struct io_timeout); list_del_init(&timeout->list); return req; } int io_timeout_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd) __must_hold(&ctx->completion_lock) { struct io_kiocb *req; spin_lock_irq(&ctx->timeout_lock); req = io_timeout_extract(ctx, cd); spin_unlock_irq(&ctx->timeout_lock); if (IS_ERR(req)) return PTR_ERR(req); io_req_task_queue_fail(req, -ECANCELED); return 0; } static void io_req_task_link_timeout(struct io_kiocb *req, struct io_tw_state *ts) { struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_kiocb *prev = timeout->prev; int ret = -ENOENT; if (prev) { if (!(req->task->flags & PF_EXITING)) { struct io_cancel_data cd = { .ctx = req->ctx, .data = prev->cqe.user_data, }; ret = io_try_cancel(req->task->io_uring, &cd, 0); } io_req_set_res(req, ret ?: -ETIME, 0); io_req_task_complete(req, ts); io_put_req(prev); } else { io_req_set_res(req, -ETIME, 0); io_req_task_complete(req, ts); } } static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *prev, *req = data->req; struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->timeout_lock, flags); prev = timeout->head; timeout->head = NULL; /* * We don't expect the list to be empty, that will only happen if we * race with the completion of the linked work. */ if (prev) { io_remove_next_linked(prev); if (!req_ref_inc_not_zero(prev)) prev = NULL; } list_del(&timeout->list); timeout->prev = prev; spin_unlock_irqrestore(&ctx->timeout_lock, flags); req->io_task_work.func = io_req_task_link_timeout; io_req_task_work_add(req); return HRTIMER_NORESTART; } static clockid_t io_timeout_get_clock(struct io_timeout_data *data) { switch (data->flags & IORING_TIMEOUT_CLOCK_MASK) { case IORING_TIMEOUT_BOOTTIME: return CLOCK_BOOTTIME; case IORING_TIMEOUT_REALTIME: return CLOCK_REALTIME; default: /* can't happen, vetted at prep time */ WARN_ON_ONCE(1); fallthrough; case 0: return CLOCK_MONOTONIC; } } static int io_linked_timeout_update(struct io_ring_ctx *ctx, __u64 user_data, struct timespec64 *ts, enum hrtimer_mode mode) __must_hold(&ctx->timeout_lock) { struct io_timeout_data *io; struct io_timeout *timeout; struct io_kiocb *req = NULL; list_for_each_entry(timeout, &ctx->ltimeout_list, list) { struct io_kiocb *tmp = cmd_to_io_kiocb(timeout); if (user_data == tmp->cqe.user_data) { req = tmp; break; } } if (!req) return -ENOENT; io = req->async_data; if (hrtimer_try_to_cancel(&io->timer) == -1) return -EALREADY; hrtimer_init(&io->timer, io_timeout_get_clock(io), mode); io->timer.function = io_link_timeout_fn; hrtimer_start(&io->timer, timespec64_to_ktime(*ts), mode); return 0; } static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data, struct timespec64 *ts, enum hrtimer_mode mode) __must_hold(&ctx->timeout_lock) { struct io_cancel_data cd = { .ctx = ctx, .data = user_data, }; struct io_kiocb *req = io_timeout_extract(ctx, &cd); struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_timeout_data *data; if (IS_ERR(req)) return PTR_ERR(req); timeout->off = 0; /* noseq */ data = req->async_data; list_add_tail(&timeout->list, &ctx->timeout_list); hrtimer_init(&data->timer, io_timeout_get_clock(data), mode); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode); return 0; } int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem); if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->buf_index || sqe->len || sqe->splice_fd_in) return -EINVAL; tr->ltimeout = false; tr->addr = READ_ONCE(sqe->addr); tr->flags = READ_ONCE(sqe->timeout_flags); if (tr->flags & IORING_TIMEOUT_UPDATE_MASK) { if (hweight32(tr->flags & IORING_TIMEOUT_CLOCK_MASK) > 1) return -EINVAL; if (tr->flags & IORING_LINK_TIMEOUT_UPDATE) tr->ltimeout = true; if (tr->flags & ~(IORING_TIMEOUT_UPDATE_MASK|IORING_TIMEOUT_ABS)) return -EINVAL; if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2))) return -EFAULT; if (tr->ts.tv_sec < 0 || tr->ts.tv_nsec < 0) return -EINVAL; } else if (tr->flags) { /* timeout removal doesn't support flags */ return -EINVAL; } return 0; } static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags) { return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL; } /* * Remove or update an existing timeout command */ int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags) { struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem); struct io_ring_ctx *ctx = req->ctx; int ret; if (!(tr->flags & IORING_TIMEOUT_UPDATE)) { struct io_cancel_data cd = { .ctx = ctx, .data = tr->addr, }; spin_lock(&ctx->completion_lock); ret = io_timeout_cancel(ctx, &cd); spin_unlock(&ctx->completion_lock); } else { enum hrtimer_mode mode = io_translate_timeout_mode(tr->flags); spin_lock_irq(&ctx->timeout_lock); if (tr->ltimeout) ret = io_linked_timeout_update(ctx, tr->addr, &tr->ts, mode); else ret = io_timeout_update(ctx, tr->addr, &tr->ts, mode); spin_unlock_irq(&ctx->timeout_lock); } if (ret < 0) req_set_fail(req); io_req_set_res(req, ret, 0); return IOU_OK; } static int __io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool is_timeout_link) { struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_timeout_data *data; unsigned flags; u32 off = READ_ONCE(sqe->off); if (sqe->buf_index || sqe->len != 1 || sqe->splice_fd_in) return -EINVAL; if (off && is_timeout_link) return -EINVAL; flags = READ_ONCE(sqe->timeout_flags); if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK | IORING_TIMEOUT_ETIME_SUCCESS | IORING_TIMEOUT_MULTISHOT)) return -EINVAL; /* more than one clock specified is invalid, obviously */ if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1) return -EINVAL; /* multishot requests only make sense with rel values */ if (!(~flags & (IORING_TIMEOUT_MULTISHOT | IORING_TIMEOUT_ABS))) return -EINVAL; INIT_LIST_HEAD(&timeout->list); timeout->off = off; if (unlikely(off && !req->ctx->off_timeout_used)) req->ctx->off_timeout_used = true; /* * for multishot reqs w/ fixed nr of repeats, repeats tracks the * remaining nr */ timeout->repeats = 0; if ((flags & IORING_TIMEOUT_MULTISHOT) && off > 0) timeout->repeats = off; if (WARN_ON_ONCE(req_has_async_data(req))) return -EFAULT; if (io_alloc_async_data(req)) return -ENOMEM; data = req->async_data; data->req = req; data->flags = flags; if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr))) return -EFAULT; if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0) return -EINVAL; data->mode = io_translate_timeout_mode(flags); hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode); if (is_timeout_link) { struct io_submit_link *link = &req->ctx->submit_state.link; if (!link->head) return -EINVAL; if (link->last->opcode == IORING_OP_LINK_TIMEOUT) return -EINVAL; timeout->head = link->last; link->last->flags |= REQ_F_ARM_LTIMEOUT; } return 0; } int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return __io_timeout_prep(req, sqe, false); } int io_link_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return __io_timeout_prep(req, sqe, true); } int io_timeout(struct io_kiocb *req, unsigned int issue_flags) { struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_ring_ctx *ctx = req->ctx; struct io_timeout_data *data = req->async_data; struct list_head *entry; u32 tail, off = timeout->off; spin_lock_irq(&ctx->timeout_lock); /* * sqe->off holds how many events that need to occur for this * timeout event to be satisfied. If it isn't set, then this is * a pure timeout request, sequence isn't used. */ if (io_is_timeout_noseq(req)) { entry = ctx->timeout_list.prev; goto add; } tail = data_race(ctx->cached_cq_tail) - atomic_read(&ctx->cq_timeouts); timeout->target_seq = tail + off; /* Update the last seq here in case io_flush_timeouts() hasn't. * This is safe because ->completion_lock is held, and submissions * and completions are never mixed in the same ->completion_lock section. */ ctx->cq_last_tm_flush = tail; /* * Insertion sort, ensuring the first entry in the list is always * the one we need first. */ list_for_each_prev(entry, &ctx->timeout_list) { struct io_timeout *nextt = list_entry(entry, struct io_timeout, list); struct io_kiocb *nxt = cmd_to_io_kiocb(nextt); if (io_is_timeout_noseq(nxt)) continue; /* nxt.seq is behind @tail, otherwise would've been completed */ if (off >= nextt->target_seq - tail) break; } add: list_add(&timeout->list, entry); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); spin_unlock_irq(&ctx->timeout_lock); return IOU_ISSUE_SKIP_COMPLETE; } void io_queue_linked_timeout(struct io_kiocb *req) { struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout); struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->timeout_lock); /* * If the back reference is NULL, then our linked request finished * before we got a chance to setup the timer */ if (timeout->head) { struct io_timeout_data *data = req->async_data; data->timer.function = io_link_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); list_add_tail(&timeout->list, &ctx->ltimeout_list); } spin_unlock_irq(&ctx->timeout_lock); /* drop submission reference */ io_put_req(req); } static bool io_match_task(struct io_kiocb *head, struct task_struct *task, bool cancel_all) __must_hold(&req->ctx->timeout_lock) { struct io_kiocb *req; if (task && head->task != task) return false; if (cancel_all) return true; io_for_each_link(req, head) { if (req->flags & REQ_F_INFLIGHT) return true; } return false; } /* Returns true if we found and killed one or more timeouts */ __cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk, bool cancel_all) { struct io_timeout *timeout, *tmp; int canceled = 0; /* * completion_lock is needed for io_match_task(). Take it before * timeout_lockfirst to keep locking ordering. */ spin_lock(&ctx->completion_lock); spin_lock_irq(&ctx->timeout_lock); list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) { struct io_kiocb *req = cmd_to_io_kiocb(timeout); if (io_match_task(req, tsk, cancel_all) && io_kill_timeout(req, -ECANCELED)) canceled++; } spin_unlock_irq(&ctx->timeout_lock); spin_unlock(&ctx->completion_lock); return canceled != 0; }