diff --git a/fs/exec.c b/fs/exec.c index a91003e28eaae23c7b56b35ad631b49897034bac..07910f5032e74ae9fcc7749d8d5c75504a68a64e 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -62,6 +62,7 @@ #include #include #include +#include #include #include @@ -1895,6 +1896,11 @@ static int bprm_execve(struct linux_binprm *bprm, struct files_struct *displaced; int retval; + /* + * Cancel any io_uring activity across execve + */ + io_uring_task_cancel(); + retval = unshare_files(&displaced); if (retval) return retval; diff --git a/fs/file.c b/fs/file.c index 21c0893f2f1df8f2feda08913cdeceeaed7a0b89..4559b5fec3bd53e8d22f79ddfa2a065cd3d527bb 100644 --- a/fs/file.c +++ b/fs/file.c @@ -21,6 +21,7 @@ #include #include #include +#include unsigned int sysctl_nr_open __read_mostly = 1024*1024; unsigned int sysctl_nr_open_min = BITS_PER_LONG; @@ -452,6 +453,7 @@ void exit_files(struct task_struct *tsk) struct files_struct * files = tsk->files; if (files) { + io_uring_files_cancel(files); task_lock(tsk); tsk->files = NULL; task_unlock(tsk); diff --git a/fs/io_uring.c b/fs/io_uring.c index 046d06266a116ee0e654c4512ceadbb86c4d02d8..ee75ba7113cfe21fd6b79e63e8e1ba6435446462 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -79,6 +79,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -284,8 +285,6 @@ struct io_ring_ctx { */ struct fixed_file_data *file_data; unsigned nr_user_files; - int ring_fd; - struct file *ring_file; /* if used, fixed mapped user buffers */ unsigned nr_user_bufs; @@ -1433,7 +1432,12 @@ static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags) WRITE_ONCE(cqe->user_data, req->user_data); WRITE_ONCE(cqe->res, res); WRITE_ONCE(cqe->flags, cflags); - } else if (ctx->cq_overflow_flushed) { + } else if (ctx->cq_overflow_flushed || req->task->io_uring->in_idle) { + /* + * If we're in ring overflow flush mode, or in task cancel mode, + * then we cannot store the request for later flushing, we need + * to drop it on the floor. + */ WRITE_ONCE(ctx->rings->cq_overflow, atomic_inc_return(&ctx->cached_cq_overflow)); } else { @@ -1591,8 +1595,12 @@ static bool io_dismantle_req(struct io_kiocb *req) static void __io_free_req_finish(struct io_kiocb *req) { + struct io_uring_task *tctx = req->task->io_uring; struct io_ring_ctx *ctx = req->ctx; + atomic_long_inc(&tctx->req_complete); + if (tctx->in_idle) + wake_up(&tctx->wait); put_task_struct(req->task); if (likely(!io_is_fallback_req(req))) @@ -1907,6 +1915,7 @@ static void io_req_free_batch_finish(struct io_ring_ctx *ctx, if (rb->to_free) __io_req_free_batch_flush(ctx, rb); if (rb->task) { + atomic_long_add(rb->task_refs, &rb->task->io_uring->req_complete); put_task_struct_many(rb->task, rb->task_refs); rb->task = NULL; } @@ -1922,8 +1931,10 @@ static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req) io_queue_next(req); if (req->task != rb->task) { - if (rb->task) + if (rb->task) { + atomic_long_add(rb->task_refs, &rb->task->io_uring->req_complete); put_task_struct_many(rb->task, rb->task_refs); + } rb->task = req->task; rb->task_refs = 0; } @@ -3978,8 +3989,7 @@ static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) return -EBADF; req->close.fd = READ_ONCE(sqe->fd); - if ((req->file && req->file->f_op == &io_uring_fops) || - req->close.fd == req->ctx->ring_fd) + if ((req->file && req->file->f_op == &io_uring_fops)) return -EBADF; req->close.put_file = NULL; @@ -5667,6 +5677,7 @@ static void io_req_drop_files(struct io_kiocb *req) wake_up(&ctx->inflight_wait); spin_unlock_irqrestore(&ctx->inflight_lock, flags); req->flags &= ~REQ_F_INFLIGHT; + put_files_struct(req->work.files); req->work.files = NULL; } @@ -6067,34 +6078,20 @@ static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req, static int io_grab_files(struct io_kiocb *req) { - int ret = -EBADF; struct io_ring_ctx *ctx = req->ctx; io_req_init_async(req); if (req->work.files || (req->flags & REQ_F_NO_FILE_TABLE)) return 0; - if (!ctx->ring_file) - return -EBADF; - rcu_read_lock(); + req->work.files = get_files_struct(current); + req->flags |= REQ_F_INFLIGHT; + spin_lock_irq(&ctx->inflight_lock); - /* - * We use the f_ops->flush() handler to ensure that we can flush - * out work accessing these files if the fd is closed. Check if - * the fd has changed since we started down this path, and disallow - * this operation if it has. - */ - if (fcheck(ctx->ring_fd) == ctx->ring_file) { - list_add(&req->inflight_entry, &ctx->inflight_list); - req->flags |= REQ_F_INFLIGHT; - req->work.files = current->files; - ret = 0; - } + list_add(&req->inflight_entry, &ctx->inflight_list); spin_unlock_irq(&ctx->inflight_lock); - rcu_read_unlock(); - - return ret; + return 0; } static inline int io_prep_work_files(struct io_kiocb *req) @@ -6459,6 +6456,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, refcount_set(&req->refs, 2); req->task = current; get_task_struct(req->task); + atomic_long_inc(&req->task->io_uring->req_issue); req->result = 0; if (unlikely(req->opcode >= IORING_OP_LAST)) @@ -6494,8 +6492,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, return io_req_set_file(state, req, READ_ONCE(sqe->fd)); } -static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr, - struct file *ring_file, int ring_fd) +static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr) { struct io_submit_state state; struct io_kiocb *link = NULL; @@ -6516,9 +6513,6 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr, io_submit_state_start(&state, ctx, nr); - ctx->ring_fd = ring_fd; - ctx->ring_file = ring_file; - for (i = 0; i < nr; i++) { const struct io_uring_sqe *sqe; struct io_kiocb *req; @@ -6687,7 +6681,7 @@ static int io_sq_thread(void *data) mutex_lock(&ctx->uring_lock); if (likely(!percpu_ref_is_dying(&ctx->refs))) - ret = io_submit_sqes(ctx, to_submit, NULL, -1); + ret = io_submit_sqes(ctx, to_submit); mutex_unlock(&ctx->uring_lock); timeout = jiffies + ctx->sq_thread_idle; } @@ -7516,6 +7510,34 @@ static int io_init_wq_offload(struct io_ring_ctx *ctx, return ret; } +static int io_uring_alloc_task_context(struct task_struct *task) +{ + struct io_uring_task *tctx; + + tctx = kmalloc(sizeof(*tctx), GFP_KERNEL); + if (unlikely(!tctx)) + return -ENOMEM; + + xa_init(&tctx->xa); + init_waitqueue_head(&tctx->wait); + tctx->last = NULL; + tctx->in_idle = 0; + atomic_long_set(&tctx->req_issue, 0); + atomic_long_set(&tctx->req_complete, 0); + task->io_uring = tctx; + return 0; +} + +void __io_uring_free(struct task_struct *tsk) +{ + struct io_uring_task *tctx = tsk->io_uring; + + WARN_ON_ONCE(!xa_empty(&tctx->xa)); + xa_destroy(&tctx->xa); + kfree(tctx); + tsk->io_uring = NULL; +} + static int io_sq_offload_start(struct io_ring_ctx *ctx, struct io_uring_params *p) { @@ -7551,6 +7573,9 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx, ctx->sqo_thread = NULL; goto err; } + ret = io_uring_alloc_task_context(ctx->sqo_thread); + if (ret) + goto err; wake_up_process(ctx->sqo_thread); } else if (p->flags & IORING_SETUP_SQ_AFF) { /* Can't have SQ_AFF without SQPOLL */ @@ -8063,7 +8088,7 @@ static bool io_wq_files_match(struct io_wq_work *work, void *data) { struct files_struct *files = data; - return work->files == files; + return !files || work->files == files; } /* @@ -8218,7 +8243,7 @@ static bool io_uring_cancel_files(struct io_ring_ctx *ctx, spin_lock_irq(&ctx->inflight_lock); list_for_each_entry(req, &ctx->inflight_list, inflight_entry) { - if (req->work.files != files) + if (files && req->work.files != files) continue; /* req is being completed, ignore */ if (!refcount_inc_not_zero(&req->refs)) @@ -8254,18 +8279,217 @@ static bool io_cancel_task_cb(struct io_wq_work *work, void *data) return io_task_match(req, task); } +static bool __io_uring_cancel_task_requests(struct io_ring_ctx *ctx, + struct task_struct *task, + struct files_struct *files) +{ + bool ret; + + ret = io_uring_cancel_files(ctx, files); + if (!files) { + enum io_wq_cancel cret; + + cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, task, true); + if (cret != IO_WQ_CANCEL_NOTFOUND) + ret = true; + + /* SQPOLL thread does its own polling */ + if (!(ctx->flags & IORING_SETUP_SQPOLL)) { + while (!list_empty_careful(&ctx->iopoll_list)) { + io_iopoll_try_reap_events(ctx); + ret = true; + } + } + + ret |= io_poll_remove_all(ctx, task); + ret |= io_kill_timeouts(ctx, task); + } + + return ret; +} + +/* + * We need to iteratively cancel requests, in case a request has dependent + * hard links. These persist even for failure of cancelations, hence keep + * looping until none are found. + */ +static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx, + struct files_struct *files) +{ + struct task_struct *task = current; + + if (ctx->flags & IORING_SETUP_SQPOLL) + task = ctx->sqo_thread; + + io_cqring_overflow_flush(ctx, true, task, files); + + while (__io_uring_cancel_task_requests(ctx, task, files)) { + io_run_task_work(); + cond_resched(); + } +} + +/* + * Note that this task has used io_uring. We use it for cancelation purposes. + */ +static int io_uring_add_task_file(struct file *file) +{ + if (unlikely(!current->io_uring)) { + int ret; + + ret = io_uring_alloc_task_context(current); + if (unlikely(ret)) + return ret; + } + if (current->io_uring->last != file) { + XA_STATE(xas, ¤t->io_uring->xa, (unsigned long) file); + void *old; + + rcu_read_lock(); + old = xas_load(&xas); + if (old != file) { + get_file(file); + xas_lock(&xas); + xas_store(&xas, file); + xas_unlock(&xas); + } + rcu_read_unlock(); + current->io_uring->last = file; + } + + return 0; +} + +/* + * Remove this io_uring_file -> task mapping. + */ +static void io_uring_del_task_file(struct file *file) +{ + struct io_uring_task *tctx = current->io_uring; + XA_STATE(xas, &tctx->xa, (unsigned long) file); + + if (tctx->last == file) + tctx->last = NULL; + + xas_lock(&xas); + file = xas_store(&xas, NULL); + xas_unlock(&xas); + + if (file) + fput(file); +} + +static void __io_uring_attempt_task_drop(struct file *file) +{ + XA_STATE(xas, ¤t->io_uring->xa, (unsigned long) file); + struct file *old; + + rcu_read_lock(); + old = xas_load(&xas); + rcu_read_unlock(); + + if (old == file) + io_uring_del_task_file(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, bool exiting) +{ + 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 (!exiting && atomic_long_read(&file->f_count) != 2) + return; + + __io_uring_attempt_task_drop(file); +} + +void __io_uring_files_cancel(struct files_struct *files) +{ + struct io_uring_task *tctx = current->io_uring; + XA_STATE(xas, &tctx->xa, 0); + + /* make sure overflow events are dropped */ + tctx->in_idle = true; + + do { + struct io_ring_ctx *ctx; + struct file *file; + + xas_lock(&xas); + file = xas_next_entry(&xas, ULONG_MAX); + xas_unlock(&xas); + + if (!file) + break; + + ctx = file->private_data; + + io_uring_cancel_task_requests(ctx, files); + if (files) + io_uring_del_task_file(file); + } while (1); +} + +static inline bool io_uring_task_idle(struct io_uring_task *tctx) +{ + return atomic_long_read(&tctx->req_issue) == + atomic_long_read(&tctx->req_complete); +} + +/* + * Find any io_uring fd that this task has registered or done IO on, and cancel + * requests. + */ +void __io_uring_task_cancel(void) +{ + struct io_uring_task *tctx = current->io_uring; + DEFINE_WAIT(wait); + long completions; + + /* make sure overflow events are dropped */ + tctx->in_idle = true; + + while (!io_uring_task_idle(tctx)) { + /* read completions before cancelations */ + completions = atomic_long_read(&tctx->req_complete); + __io_uring_files_cancel(NULL); + + prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE); + + /* + * If we've seen completions, retry. This avoids a race where + * a completion comes in before we did prepare_to_wait(). + */ + if (completions != atomic_long_read(&tctx->req_complete)) + continue; + if (io_uring_task_idle(tctx)) + break; + schedule(); + } + + finish_wait(&tctx->wait, &wait); + tctx->in_idle = false; +} + static int io_uring_flush(struct file *file, void *data) { struct io_ring_ctx *ctx = file->private_data; - io_uring_cancel_files(ctx, data); - /* * If the task is going away, cancel work it may have pending */ if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) - io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, current, true); + data = NULL; + io_uring_cancel_task_requests(ctx, data); + io_uring_attempt_task_drop(file, !data); return 0; } @@ -8379,8 +8603,11 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, wake_up(&ctx->sqo_wait); submitted = to_submit; } else if (to_submit) { + ret = io_uring_add_task_file(f.file); + if (unlikely(ret)) + goto out; mutex_lock(&ctx->uring_lock); - submitted = io_submit_sqes(ctx, to_submit, f.file, fd); + submitted = io_submit_sqes(ctx, to_submit); mutex_unlock(&ctx->uring_lock); if (submitted != to_submit) @@ -8590,6 +8817,7 @@ static int io_uring_get_fd(struct io_ring_ctx *ctx) file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx, O_RDWR | O_CLOEXEC); if (IS_ERR(file)) { +err_fd: put_unused_fd(ret); ret = PTR_ERR(file); goto err; @@ -8598,6 +8826,10 @@ static int io_uring_get_fd(struct io_ring_ctx *ctx) #if defined(CONFIG_UNIX) ctx->ring_sock->file = file; #endif + if (unlikely(io_uring_add_task_file(file))) { + file = ERR_PTR(-ENOMEM); + goto err_fd; + } fd_install(ret, file); return ret; err: diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h new file mode 100644 index 0000000000000000000000000000000000000000..c09135a1ef1323d30370ebef40182416e8e16c61 --- /dev/null +++ b/include/linux/io_uring.h @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _LINUX_IO_URING_H +#define _LINUX_IO_URING_H + +#include +#include +#include + +struct io_uring_task { + /* submission side */ + struct xarray xa; + struct wait_queue_head wait; + struct file *last; + atomic_long_t req_issue; + + /* completion side */ + bool in_idle ____cacheline_aligned_in_smp; + atomic_long_t req_complete; +}; + +#if defined(CONFIG_IO_URING) +void __io_uring_task_cancel(void); +void __io_uring_files_cancel(struct files_struct *files); +void __io_uring_free(struct task_struct *tsk); + +static inline void io_uring_task_cancel(void) +{ + if (current->io_uring && !xa_empty(¤t->io_uring->xa)) + __io_uring_task_cancel(); +} +static inline void io_uring_files_cancel(struct files_struct *files) +{ + if (current->io_uring && !xa_empty(¤t->io_uring->xa)) + __io_uring_files_cancel(files); +} +static inline void io_uring_free(struct task_struct *tsk) +{ + if (tsk->io_uring) + __io_uring_free(tsk); +} +#else +static inline void io_uring_task_cancel(void) +{ +} +static inline void io_uring_files_cancel(struct files_struct *files) +{ +} +static inline void io_uring_free(struct task_struct *tsk) +{ +} +#endif + +#endif diff --git a/include/linux/sched.h b/include/linux/sched.h index afe01e232935fa44c11272442b75da197bd58353..8bf2295ebee48f95a2afc33cd9703a7c0a3837af 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -63,6 +63,7 @@ struct sighand_struct; struct signal_struct; struct task_delay_info; struct task_group; +struct io_uring_task; /* * Task state bitmask. NOTE! These bits are also @@ -935,6 +936,10 @@ struct task_struct { /* Open file information: */ struct files_struct *files; +#ifdef CONFIG_IO_URING + struct io_uring_task *io_uring; +#endif + /* Namespaces: */ struct nsproxy *nsproxy; diff --git a/init/init_task.c b/init/init_task.c index f6889fce64af7c848e64912c92add9abfb5f0141..a56f0abb63e934e3d3de3f9cabf7dd2d9cc760f0 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -114,6 +114,9 @@ struct task_struct init_task .thread = INIT_THREAD, .fs = &init_fs, .files = &init_files, +#ifdef CONFIG_IO_URING + .io_uring = NULL, +#endif .signal = &init_signals, .sighand = &init_sighand, .nsproxy = &init_nsproxy, diff --git a/kernel/fork.c b/kernel/fork.c index da8d360fb0326e18a059313c8b21fe93220b5eb5..a3795aaaab5c580598aacd1299820d9a76b3aad0 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -95,6 +95,7 @@ #include #include #include +#include #include #include @@ -728,6 +729,7 @@ void __put_task_struct(struct task_struct *tsk) WARN_ON(refcount_read(&tsk->usage)); WARN_ON(tsk == current); + io_uring_free(tsk); cgroup_free(tsk); task_numa_free(tsk, true); security_task_free(tsk); @@ -1983,6 +1985,10 @@ static __latent_entropy struct task_struct *copy_process( p->vtime.state = VTIME_INACTIVE; #endif +#ifdef CONFIG_IO_URING + p->io_uring = NULL; +#endif + #if defined(SPLIT_RSS_COUNTING) memset(&p->rss_stat, 0, sizeof(p->rss_stat)); #endif