diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-01-10 12:39:38 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-01-10 12:39:38 -0800 |
commit | d430adfea8d2c5baa186cabb130235f72fecbd5b (patch) | |
tree | 3a40c99dcabb507fbce77ca5c71b4a27bad7d98f | |
parent | 28318f53503090fcd8fd27c49445396ea2ace44b (diff) | |
parent | d9d05217cb6990b9a56e13b56e7a1b71e2551f6c (diff) |
Merge tag 'io_uring-5.11-2021-01-10' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
"A bit larger than I had hoped at this point, but it's all changes that
will be directed towards stable anyway. In detail:
- Fix a merge window regression on error return (Matthew)
- Remove useless variable declaration/assignment (Ye Bin)
- IOPOLL fixes (Pavel)
- Exit and cancelation fixes (Pavel)
- fasync lockdep complaint fix (Pavel)
- Ensure SQPOLL is synchronized with creator life time (Pavel)"
* tag 'io_uring-5.11-2021-01-10' of git://git.kernel.dk/linux-block:
io_uring: stop SQPOLL submit on creator's death
io_uring: add warn_once for io_uring_flush()
io_uring: inline io_uring_attempt_task_drop()
io_uring: io_rw_reissue lockdep annotations
io_uring: synchronise ev_posted() with waitqueues
io_uring: dont kill fasync under completion_lock
io_uring: trigger eventfd for IOPOLL
io_uring: Fix return value from alloc_fixed_file_ref_node
io_uring: Delete useless variable ‘id’ in io_prep_async_work
io_uring: cancel more aggressively in exit_work
io_uring: drop file refs after task cancel
io_uring: patch up IOPOLL overflow_flush sync
io_uring: synchronise IOPOLL on task_submit fail
-rw-r--r-- | fs/io_uring.c | 256 |
1 files changed, 167 insertions, 89 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index ca46f314640b..2f305c097bd5 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -262,6 +262,7 @@ struct io_ring_ctx { unsigned int drain_next: 1; unsigned int eventfd_async: 1; unsigned int restricted: 1; + unsigned int sqo_dead: 1; /* * Ring buffer of indices into array of io_uring_sqe, which is @@ -992,6 +993,9 @@ enum io_mem_account { ACCT_PINNED, }; +static void __io_uring_cancel_task_requests(struct io_ring_ctx *ctx, + struct task_struct *task); + static void destroy_fixed_file_ref_node(struct fixed_file_ref_node *ref_node); static struct fixed_file_ref_node *alloc_fixed_file_ref_node( struct io_ring_ctx *ctx); @@ -1342,11 +1346,6 @@ static void __io_commit_cqring(struct io_ring_ctx *ctx) /* order cqe stores with ring update */ smp_store_release(&rings->cq.tail, ctx->cached_cq_tail); - - if (wq_has_sleeper(&ctx->cq_wait)) { - wake_up_interruptible(&ctx->cq_wait); - kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); - } } static void io_put_identity(struct io_uring_task *tctx, struct io_kiocb *req) @@ -1520,10 +1519,8 @@ static void io_prep_async_work(struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; struct io_ring_ctx *ctx = req->ctx; - struct io_identity *id; io_req_init_async(req); - id = req->work.identity; if (req->flags & REQ_F_FORCE_ASYNC) req->work.flags |= IO_WQ_WORK_CONCURRENT; @@ -1704,18 +1701,42 @@ static inline unsigned __io_cqring_events(struct io_ring_ctx *ctx) static void io_cqring_ev_posted(struct io_ring_ctx *ctx) { + /* see waitqueue_active() comment */ + smp_mb(); + if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); if (ctx->sq_data && waitqueue_active(&ctx->sq_data->wait)) wake_up(&ctx->sq_data->wait); if (io_should_trigger_evfd(ctx)) eventfd_signal(ctx->cq_ev_fd, 1); + if (waitqueue_active(&ctx->cq_wait)) { + wake_up_interruptible(&ctx->cq_wait); + kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); + } +} + +static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx) +{ + /* see waitqueue_active() comment */ + smp_mb(); + + if (ctx->flags & IORING_SETUP_SQPOLL) { + if (waitqueue_active(&ctx->wait)) + wake_up(&ctx->wait); + } + if (io_should_trigger_evfd(ctx)) + eventfd_signal(ctx->cq_ev_fd, 1); + if (waitqueue_active(&ctx->cq_wait)) { + wake_up_interruptible(&ctx->cq_wait); + kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); + } } /* Returns true if there are no backlogged entries after the flush */ -static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force, - struct task_struct *tsk, - struct files_struct *files) +static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force, + struct task_struct *tsk, + struct files_struct *files) { struct io_rings *rings = ctx->rings; struct io_kiocb *req, *tmp; @@ -1768,6 +1789,20 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force, return all_flushed; } +static void io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force, + struct task_struct *tsk, + struct files_struct *files) +{ + if (test_bit(0, &ctx->cq_check_overflow)) { + /* iopoll syncs against uring_lock, not completion_lock */ + if (ctx->flags & IORING_SETUP_IOPOLL) + mutex_lock(&ctx->uring_lock); + __io_cqring_overflow_flush(ctx, force, tsk, files); + if (ctx->flags & IORING_SETUP_IOPOLL) + mutex_unlock(&ctx->uring_lock); + } +} + static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags) { struct io_ring_ctx *ctx = req->ctx; @@ -2127,14 +2162,14 @@ static void __io_req_task_submit(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; - if (!__io_sq_thread_acquire_mm(ctx) && - !__io_sq_thread_acquire_files(ctx)) { - mutex_lock(&ctx->uring_lock); + mutex_lock(&ctx->uring_lock); + if (!ctx->sqo_dead && + !__io_sq_thread_acquire_mm(ctx) && + !__io_sq_thread_acquire_files(ctx)) __io_queue_sqe(req, NULL); - mutex_unlock(&ctx->uring_lock); - } else { + else __io_req_task_cancel(req, -EFAULT); - } + mutex_unlock(&ctx->uring_lock); } static void io_req_task_submit(struct callback_head *cb) @@ -2313,20 +2348,8 @@ static void io_double_put_req(struct io_kiocb *req) io_free_req(req); } -static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush) +static unsigned io_cqring_events(struct io_ring_ctx *ctx) { - if (test_bit(0, &ctx->cq_check_overflow)) { - /* - * noflush == true is from the waitqueue handler, just ensure - * we wake up the task, and the next invocation will flush the - * entries. We cannot safely to it from here. - */ - if (noflush) - return -1U; - - io_cqring_overflow_flush(ctx, false, NULL, NULL); - } - /* See comment at the top of this file */ smp_rmb(); return __io_cqring_events(ctx); @@ -2424,8 +2447,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, } io_commit_cqring(ctx); - if (ctx->flags & IORING_SETUP_SQPOLL) - io_cqring_ev_posted(ctx); + io_cqring_ev_posted_iopoll(ctx); io_req_free_batch_finish(ctx, &rb); if (!list_empty(&again)) @@ -2551,7 +2573,9 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min) * If we do, we can potentially be spinning for commands that * already triggered a CQE (eg in error). */ - if (io_cqring_events(ctx, false)) + if (test_bit(0, &ctx->cq_check_overflow)) + __io_cqring_overflow_flush(ctx, false, NULL, NULL); + if (io_cqring_events(ctx)) break; /* @@ -2668,6 +2692,8 @@ static bool io_rw_reissue(struct io_kiocb *req, long res) if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker()) return false; + lockdep_assert_held(&req->ctx->uring_lock); + ret = io_sq_thread_acquire_mm_files(req->ctx, req); if (io_resubmit_prep(req, ret)) { @@ -6826,7 +6852,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr) /* if we have a backlog and couldn't flush it all, return BUSY */ if (test_bit(0, &ctx->sq_check_overflow)) { - if (!io_cqring_overflow_flush(ctx, false, NULL, NULL)) + if (!__io_cqring_overflow_flush(ctx, false, NULL, NULL)) return -EBUSY; } @@ -6928,7 +6954,8 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) if (!list_empty(&ctx->iopoll_list)) io_do_iopoll(ctx, &nr_events, 0); - if (to_submit && likely(!percpu_ref_is_dying(&ctx->refs))) + if (to_submit && !ctx->sqo_dead && + likely(!percpu_ref_is_dying(&ctx->refs))) ret = io_submit_sqes(ctx, to_submit); mutex_unlock(&ctx->uring_lock); } @@ -7089,7 +7116,7 @@ struct io_wait_queue { unsigned nr_timeouts; }; -static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush) +static inline bool io_should_wake(struct io_wait_queue *iowq) { struct io_ring_ctx *ctx = iowq->ctx; @@ -7098,7 +7125,7 @@ static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush) * started waiting. For timeouts, we always want to return to userspace, * regardless of event count. */ - return io_cqring_events(ctx, noflush) >= iowq->to_wait || + return io_cqring_events(ctx) >= iowq->to_wait || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts; } @@ -7108,11 +7135,13 @@ static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode, struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq); - /* use noflush == true, as we can't safely rely on locking context */ - if (!io_should_wake(iowq, true)) - return -1; - - return autoremove_wake_function(curr, mode, wake_flags, key); + /* + * Cannot safely flush overflowed CQEs from here, ensure we wake up + * the task, and the next invocation will do it. + */ + if (io_should_wake(iowq) || test_bit(0, &iowq->ctx->cq_check_overflow)) + return autoremove_wake_function(curr, mode, wake_flags, key); + return -1; } static int io_run_task_work_sig(void) @@ -7149,7 +7178,8 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, int ret = 0; do { - if (io_cqring_events(ctx, false) >= min_events) + io_cqring_overflow_flush(ctx, false, NULL, NULL); + if (io_cqring_events(ctx) >= min_events) return 0; if (!io_run_task_work()) break; @@ -7177,6 +7207,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); trace_io_uring_cqring_wait(ctx, min_events); do { + io_cqring_overflow_flush(ctx, false, NULL, NULL); prepare_to_wait_exclusive(&ctx->wait, &iowq.wq, TASK_INTERRUPTIBLE); /* make sure we run task_work before checking for signals */ @@ -7185,8 +7216,10 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, continue; else if (ret < 0) break; - if (io_should_wake(&iowq, false)) + if (io_should_wake(&iowq)) break; + if (test_bit(0, &ctx->cq_check_overflow)) + continue; if (uts) { timeout = schedule_timeout(timeout); if (timeout == 0) { @@ -7684,12 +7717,12 @@ static struct fixed_file_ref_node *alloc_fixed_file_ref_node( ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); if (!ref_node) - return ERR_PTR(-ENOMEM); + return NULL; if (percpu_ref_init(&ref_node->refs, io_file_data_ref_zero, 0, GFP_KERNEL)) { kfree(ref_node); - return ERR_PTR(-ENOMEM); + return NULL; } INIT_LIST_HEAD(&ref_node->node); INIT_LIST_HEAD(&ref_node->file_list); @@ -7783,9 +7816,9 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, } ref_node = alloc_fixed_file_ref_node(ctx); - if (IS_ERR(ref_node)) { + if (!ref_node) { io_sqe_files_unregister(ctx); - return PTR_ERR(ref_node); + return -ENOMEM; } io_sqe_files_set_node(file_data, ref_node); @@ -7885,8 +7918,8 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx, return -EINVAL; ref_node = alloc_fixed_file_ref_node(ctx); - if (IS_ERR(ref_node)) - return PTR_ERR(ref_node); + if (!ref_node) + return -ENOMEM; done = 0; fds = u64_to_user_ptr(up->fds); @@ -8624,7 +8657,8 @@ static __poll_t io_uring_poll(struct file *file, poll_table *wait) smp_rmb(); if (!io_sqring_full(ctx)) mask |= EPOLLOUT | EPOLLWRNORM; - if (io_cqring_events(ctx, false)) + io_cqring_overflow_flush(ctx, false, NULL, NULL); + if (io_cqring_events(ctx)) mask |= EPOLLIN | EPOLLRDNORM; return mask; @@ -8663,7 +8697,7 @@ static void io_ring_exit_work(struct work_struct *work) * as nobody else will be looking for them. */ do { - io_iopoll_try_reap_events(ctx); + __io_uring_cancel_task_requests(ctx, NULL); } while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20)); io_ring_ctx_free(ctx); } @@ -8679,10 +8713,14 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) { mutex_lock(&ctx->uring_lock); percpu_ref_kill(&ctx->refs); + + if (WARN_ON_ONCE((ctx->flags & IORING_SETUP_SQPOLL) && !ctx->sqo_dead)) + ctx->sqo_dead = 1; + /* if force is set, the ring is going away. always drop after that */ ctx->cq_overflow_flushed = 1; if (ctx->rings) - io_cqring_overflow_flush(ctx, true, NULL, NULL); + __io_cqring_overflow_flush(ctx, true, NULL, NULL); mutex_unlock(&ctx->uring_lock); io_kill_timeouts(ctx, NULL, NULL); @@ -8818,9 +8856,11 @@ static void __io_uring_cancel_task_requests(struct io_ring_ctx *ctx, enum io_wq_cancel cret; bool ret = false; - cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, &cancel, true); - if (cret != IO_WQ_CANCEL_NOTFOUND) - ret = true; + if (ctx->io_wq) { + cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, + &cancel, true); + ret |= (cret != IO_WQ_CANCEL_NOTFOUND); + } /* SQPOLL thread does its own polling */ if (!(ctx->flags & IORING_SETUP_SQPOLL)) { @@ -8839,6 +8879,18 @@ static void __io_uring_cancel_task_requests(struct io_ring_ctx *ctx, } } +static void io_disable_sqo_submit(struct io_ring_ctx *ctx) +{ + WARN_ON_ONCE(ctx->sqo_task != current); + + mutex_lock(&ctx->uring_lock); + ctx->sqo_dead = 1; + mutex_unlock(&ctx->uring_lock); + + /* make sure callers enter the ring to get error */ + io_ring_set_wakeup_flag(ctx); +} + /* * We need to iteratively cancel requests, in case a request has dependent * hard links. These persist even for failure of cancelations, hence keep @@ -8850,15 +8902,15 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx, struct task_struct *task = current; if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) { + /* for SQPOLL only sqo_task has task notes */ + io_disable_sqo_submit(ctx); task = ctx->sq_data->thread; atomic_inc(&task->io_uring->in_idle); io_sq_thread_park(ctx->sq_data); } io_cancel_defer_files(ctx, task, files); - io_ring_submit_lock(ctx, (ctx->flags & IORING_SETUP_IOPOLL)); io_cqring_overflow_flush(ctx, true, task, files); - io_ring_submit_unlock(ctx, (ctx->flags & IORING_SETUP_IOPOLL)); if (!files) __io_uring_cancel_task_requests(ctx, task); @@ -8931,20 +8983,12 @@ static void io_uring_del_task_file(struct file *file) fput(file); } -/* - * Drop task note for this file if we're the only ones that hold it after - * pending fput() - */ -static void io_uring_attempt_task_drop(struct file *file) +static void io_uring_remove_task_files(struct io_uring_task *tctx) { - if (!current->io_uring) - return; - /* - * fput() is pending, will be 2 if the only other ref is our potential - * task file note. If the task is exiting, drop regardless of count. - */ - if (fatal_signal_pending(current) || (current->flags & PF_EXITING) || - atomic_long_read(&file->f_count) == 2) + struct file *file; + unsigned long index; + + xa_for_each(&tctx->xa, index, file) io_uring_del_task_file(file); } @@ -8956,16 +9000,12 @@ void __io_uring_files_cancel(struct files_struct *files) /* make sure overflow events are dropped */ atomic_inc(&tctx->in_idle); - - xa_for_each(&tctx->xa, index, file) { - struct io_ring_ctx *ctx = file->private_data; - - io_uring_cancel_task_requests(ctx, files); - if (files) - io_uring_del_task_file(file); - } - + xa_for_each(&tctx->xa, index, file) + io_uring_cancel_task_requests(file->private_data, files); atomic_dec(&tctx->in_idle); + + if (files) + io_uring_remove_task_files(tctx); } static s64 tctx_inflight(struct io_uring_task *tctx) @@ -9028,11 +9068,39 @@ void __io_uring_task_cancel(void) } while (1); atomic_dec(&tctx->in_idle); + + io_uring_remove_task_files(tctx); } static int io_uring_flush(struct file *file, void *data) { - io_uring_attempt_task_drop(file); + struct io_uring_task *tctx = current->io_uring; + struct io_ring_ctx *ctx = file->private_data; + + if (!tctx) + return 0; + + /* we should have cancelled and erased it before PF_EXITING */ + WARN_ON_ONCE((current->flags & PF_EXITING) && + xa_load(&tctx->xa, (unsigned long)file)); + + /* + * fput() is pending, will be 2 if the only other ref is our potential + * task file note. If the task is exiting, drop regardless of count. + */ + if (atomic_long_read(&file->f_count) != 2) + return 0; + + if (ctx->flags & IORING_SETUP_SQPOLL) { + /* there is only one file note, which is owned by sqo_task */ + WARN_ON_ONCE((ctx->sqo_task == current) == + !xa_load(&tctx->xa, (unsigned long)file)); + + io_disable_sqo_submit(ctx); + } + + if (!(ctx->flags & IORING_SETUP_SQPOLL) || ctx->sqo_task == current) + io_uring_del_task_file(file); return 0; } @@ -9106,8 +9174,9 @@ static unsigned long io_uring_nommu_get_unmapped_area(struct file *file, #endif /* !CONFIG_MMU */ -static void io_sqpoll_wait_sq(struct io_ring_ctx *ctx) +static int io_sqpoll_wait_sq(struct io_ring_ctx *ctx) { + int ret = 0; DEFINE_WAIT(wait); do { @@ -9116,6 +9185,11 @@ static void io_sqpoll_wait_sq(struct io_ring_ctx *ctx) prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE); + if (unlikely(ctx->sqo_dead)) { + ret = -EOWNERDEAD; + goto out; + } + if (!io_sqring_full(ctx)) break; @@ -9123,6 +9197,8 @@ static void io_sqpoll_wait_sq(struct io_ring_ctx *ctx) } while (!signal_pending(current)); finish_wait(&ctx->sqo_sq_wait, &wait); +out: + return ret; } static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz, @@ -9194,17 +9270,18 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, */ ret = 0; if (ctx->flags & IORING_SETUP_SQPOLL) { - if (!list_empty_careful(&ctx->cq_overflow_list)) { - bool needs_lock = ctx->flags & IORING_SETUP_IOPOLL; + io_cqring_overflow_flush(ctx, false, NULL, NULL); - io_ring_submit_lock(ctx, needs_lock); - io_cqring_overflow_flush(ctx, false, NULL, NULL); - io_ring_submit_unlock(ctx, needs_lock); - } + ret = -EOWNERDEAD; + if (unlikely(ctx->sqo_dead)) + goto out; if (flags & IORING_ENTER_SQ_WAKEUP) wake_up(&ctx->sq_data->wait); - if (flags & IORING_ENTER_SQ_WAIT) - io_sqpoll_wait_sq(ctx); + if (flags & IORING_ENTER_SQ_WAIT) { + ret = io_sqpoll_wait_sq(ctx); + if (ret) + goto out; + } submitted = to_submit; } else if (to_submit) { ret = io_uring_add_task_file(ctx, f.file); @@ -9631,6 +9708,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p, trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); return ret; err: + io_disable_sqo_submit(ctx); io_ring_ctx_wait_and_kill(ctx); return ret; } |