diff options
| -rw-r--r-- | include/linux/io_uring_types.h | 2 | ||||
| -rw-r--r-- | include/uapi/linux/io_uring.h | 2 | ||||
| -rw-r--r-- | io_uring/Makefile | 3 | ||||
| -rw-r--r-- | io_uring/cancel.c | 5 | ||||
| -rw-r--r-- | io_uring/io_uring.c | 3 | ||||
| -rw-r--r-- | io_uring/opdef.c | 9 | ||||
| -rw-r--r-- | io_uring/waitid.c | 372 | ||||
| -rw-r--r-- | io_uring/waitid.h | 15 |
8 files changed, 410 insertions, 1 deletions
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 13d19b9be9f4..fe1c5d4ec56c 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -313,6 +313,8 @@ struct io_ring_ctx { struct list_head cq_overflow_list; struct io_hash_table cancel_table; + struct hlist_head waitid_list; + const struct cred *sq_creds; /* cred used for __io_sq_thread() */ struct io_sq_data *sq_data; /* if using sq thread polling */ diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index d127948b0d8a..683ac2b74721 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -65,6 +65,7 @@ struct io_uring_sqe { __u32 xattr_flags; __u32 msg_ring_flags; __u32 uring_cmd_flags; + __u32 waitid_flags; }; __u64 user_data; /* data to be passed back at completion time */ /* pack this to avoid bogus arm OABI complaints */ @@ -241,6 +242,7 @@ enum io_uring_op { IORING_OP_SEND_ZC, IORING_OP_SENDMSG_ZC, IORING_OP_READ_MULTISHOT, + IORING_OP_WAITID, /* this goes last, obviously */ IORING_OP_LAST, diff --git a/io_uring/Makefile b/io_uring/Makefile index 8cc8e5387a75..7bd64e442567 100644 --- a/io_uring/Makefile +++ b/io_uring/Makefile @@ -7,5 +7,6 @@ obj-$(CONFIG_IO_URING) += io_uring.o xattr.o nop.o fs.o splice.o \ openclose.o uring_cmd.o epoll.o \ statx.o net.o msg_ring.o timeout.o \ sqpoll.o fdinfo.o tctx.o poll.o \ - cancel.o kbuf.o rsrc.o rw.o opdef.o notif.o + cancel.o kbuf.o rsrc.o rw.o opdef.o \ + notif.o waitid.o obj-$(CONFIG_IO_WQ) += io-wq.o diff --git a/io_uring/cancel.c b/io_uring/cancel.c index 7b23607cf4af..eb77a51c5a79 100644 --- a/io_uring/cancel.c +++ b/io_uring/cancel.c @@ -15,6 +15,7 @@ #include "tctx.h" #include "poll.h" #include "timeout.h" +#include "waitid.h" #include "cancel.h" struct io_cancel { @@ -119,6 +120,10 @@ int io_try_cancel(struct io_uring_task *tctx, struct io_cancel_data *cd, if (ret != -ENOENT) return ret; + ret = io_waitid_cancel(ctx, cd, issue_flags); + if (ret != -ENOENT) + return ret; + spin_lock(&ctx->completion_lock); if (!(cd->flags & IORING_ASYNC_CANCEL_FD)) ret = io_timeout_cancel(ctx, cd); diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 783ed0fff71b..2dff4772bf14 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -92,6 +92,7 @@ #include "cancel.h" #include "net.h" #include "notif.h" +#include "waitid.h" #include "timeout.h" #include "poll.h" @@ -348,6 +349,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) INIT_LIST_HEAD(&ctx->tctx_list); ctx->submit_state.free_list.next = NULL; INIT_WQ_LIST(&ctx->locked_free_list); + INIT_HLIST_HEAD(&ctx->waitid_list); INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func); INIT_WQ_LIST(&ctx->submit_state.compl_reqs); return ctx; @@ -3303,6 +3305,7 @@ static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx, ret |= io_cancel_defer_files(ctx, task, cancel_all); mutex_lock(&ctx->uring_lock); ret |= io_poll_remove_all(ctx, task, cancel_all); + ret |= io_waitid_remove_all(ctx, task, cancel_all); mutex_unlock(&ctx->uring_lock); ret |= io_kill_timeouts(ctx, task, cancel_all); if (task) diff --git a/io_uring/opdef.c b/io_uring/opdef.c index a3fb1f9b3998..aadcbf7136b0 100644 --- a/io_uring/opdef.c +++ b/io_uring/opdef.c @@ -33,6 +33,7 @@ #include "poll.h" #include "cancel.h" #include "rw.h" +#include "waitid.h" static int io_no_issue(struct io_kiocb *req, unsigned int issue_flags) { @@ -439,6 +440,10 @@ const struct io_issue_def io_issue_defs[] = { .prep = io_read_mshot_prep, .issue = io_read_mshot, }, + [IORING_OP_WAITID] = { + .prep = io_waitid_prep, + .issue = io_waitid, + }, }; const struct io_cold_def io_cold_defs[] = { @@ -661,6 +666,10 @@ const struct io_cold_def io_cold_defs[] = { [IORING_OP_READ_MULTISHOT] = { .name = "READ_MULTISHOT", }, + [IORING_OP_WAITID] = { + .name = "WAITID", + .async_size = sizeof(struct io_waitid_async), + }, }; const char *io_uring_get_opcode(u8 opcode) diff --git a/io_uring/waitid.c b/io_uring/waitid.c new file mode 100644 index 000000000000..6f851978606d --- /dev/null +++ b/io_uring/waitid.c @@ -0,0 +1,372 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Support for async notification of waitid + */ +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/file.h> +#include <linux/compat.h> +#include <linux/io_uring.h> + +#include <uapi/linux/io_uring.h> + +#include "io_uring.h" +#include "cancel.h" +#include "waitid.h" +#include "../kernel/exit.h" + +static void io_waitid_cb(struct io_kiocb *req, struct io_tw_state *ts); + +#define IO_WAITID_CANCEL_FLAG BIT(31) +#define IO_WAITID_REF_MASK GENMASK(30, 0) + +struct io_waitid { + struct file *file; + int which; + pid_t upid; + int options; + atomic_t refs; + struct wait_queue_head *head; + struct siginfo __user *infop; + struct waitid_info info; +}; + +static void io_waitid_free(struct io_kiocb *req) +{ + struct io_waitid_async *iwa = req->async_data; + + put_pid(iwa->wo.wo_pid); + kfree(req->async_data); + req->async_data = NULL; + req->flags &= ~REQ_F_ASYNC_DATA; +} + +#ifdef CONFIG_COMPAT +static bool io_waitid_compat_copy_si(struct io_waitid *iw, int signo) +{ + struct compat_siginfo __user *infop; + bool ret; + + infop = (struct compat_siginfo __user *) iw->infop; + + if (!user_write_access_begin(infop, sizeof(*infop))) + return false; + + unsafe_put_user(signo, &infop->si_signo, Efault); + unsafe_put_user(0, &infop->si_errno, Efault); + unsafe_put_user(iw->info.cause, &infop->si_code, Efault); + unsafe_put_user(iw->info.pid, &infop->si_pid, Efault); + unsafe_put_user(iw->info.uid, &infop->si_uid, Efault); + unsafe_put_user(iw->info.status, &infop->si_status, Efault); + ret = true; +done: + user_write_access_end(); + return ret; +Efault: + ret = false; + goto done; +} +#endif + +static bool io_waitid_copy_si(struct io_kiocb *req, int signo) +{ + struct io_waitid *iw = io_kiocb_to_cmd(req, struct io_waitid); + bool ret; + + if (!iw->infop) + return true; + +#ifdef CONFIG_COMPAT + if (req->ctx->compat) + return io_waitid_compat_copy_si(iw, signo); +#endif + + if (!user_write_access_begin(iw->infop, sizeof(*iw->infop))) + return false; + + unsafe_put_user(signo, &iw->infop->si_signo, Efault); + unsafe_put_user(0, &iw->infop->si_errno, Efault); + unsafe_put_user(iw->info.cause, &iw->infop->si_code, Efault); + unsafe_put_user(iw->info.pid, &iw->infop->si_pid, Efault); + unsafe_put_user(iw->info.uid, &iw->infop->si_uid, Efault); + unsafe_put_user(iw->info.status, &iw->infop->si_status, Efault); + ret = true; +done: + user_write_access_end(); + return ret; +Efault: + ret = false; + goto done; +} + +static int io_waitid_finish(struct io_kiocb *req, int ret) +{ + int signo = 0; + + if (ret > 0) { + signo = SIGCHLD; + ret = 0; + } + + if (!io_waitid_copy_si(req, signo)) + ret = -EFAULT; + io_waitid_free(req); + return ret; +} + +static void io_waitid_complete(struct io_kiocb *req, int ret) +{ + struct io_waitid *iw = io_kiocb_to_cmd(req, struct io_waitid); + struct io_tw_state ts = { .locked = true }; + + /* anyone completing better be holding a reference */ + WARN_ON_ONCE(!(atomic_read(&iw->refs) & IO_WAITID_REF_MASK)); + + lockdep_assert_held(&req->ctx->uring_lock); + + /* + * Did cancel find it meanwhile? + */ + if (hlist_unhashed(&req->hash_node)) + return; + + hlist_del_init(&req->hash_node); + + ret = io_waitid_finish(req, ret); + if (ret < 0) + req_set_fail(req); + io_req_set_res(req, ret, 0); + io_req_task_complete(req, &ts); +} + +static bool __io_waitid_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req) +{ + struct io_waitid *iw = io_kiocb_to_cmd(req, struct io_waitid); + struct io_waitid_async *iwa = req->async_data; + + /* + * Mark us canceled regardless of ownership. This will prevent a + * potential retry from a spurious wakeup. + */ + atomic_or(IO_WAITID_CANCEL_FLAG, &iw->refs); + + /* claim ownership */ + if (atomic_fetch_inc(&iw->refs) & IO_WAITID_REF_MASK) + return false; + + spin_lock_irq(&iw->head->lock); + list_del_init(&iwa->wo.child_wait.entry); + spin_unlock_irq(&iw->head->lock); + io_waitid_complete(req, -ECANCELED); + return true; +} + +int io_waitid_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd, + unsigned int issue_flags) +{ + struct hlist_node *tmp; + struct io_kiocb *req; + int nr = 0; + + if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_FD_FIXED)) + return -ENOENT; + + io_ring_submit_lock(ctx, issue_flags); + hlist_for_each_entry_safe(req, tmp, &ctx->waitid_list, hash_node) { + if (req->cqe.user_data != cd->data && + !(cd->flags & IORING_ASYNC_CANCEL_ANY)) + continue; + if (__io_waitid_cancel(ctx, req)) + nr++; + if (!(cd->flags & IORING_ASYNC_CANCEL_ALL)) + break; + } + io_ring_submit_unlock(ctx, issue_flags); + + if (nr) + return nr; + + return -ENOENT; +} + +bool io_waitid_remove_all(struct io_ring_ctx *ctx, struct task_struct *task, + bool cancel_all) +{ + struct hlist_node *tmp; + struct io_kiocb *req; + bool found = false; + + lockdep_assert_held(&ctx->uring_lock); + + hlist_for_each_entry_safe(req, tmp, &ctx->waitid_list, hash_node) { + if (!io_match_task_safe(req, task, cancel_all)) + continue; + __io_waitid_cancel(ctx, req); + found = true; + } + + return found; +} + +static inline bool io_waitid_drop_issue_ref(struct io_kiocb *req) +{ + struct io_waitid *iw = io_kiocb_to_cmd(req, struct io_waitid); + struct io_waitid_async *iwa = req->async_data; + + if (!atomic_sub_return(1, &iw->refs)) + return false; + + /* + * Wakeup triggered, racing with us. It was prevented from + * completing because of that, queue up the tw to do that. + */ + req->io_task_work.func = io_waitid_cb; + io_req_task_work_add(req); + remove_wait_queue(iw->head, &iwa->wo.child_wait); + return true; +} + +static void io_waitid_cb(struct io_kiocb *req, struct io_tw_state *ts) +{ + struct io_waitid_async *iwa = req->async_data; + struct io_ring_ctx *ctx = req->ctx; + int ret; + + io_tw_lock(ctx, ts); + + ret = __do_wait(&iwa->wo); + + /* + * If we get -ERESTARTSYS here, we need to re-arm and check again + * to ensure we get another callback. If the retry works, then we can + * just remove ourselves from the waitqueue again and finish the + * request. + */ + if (unlikely(ret == -ERESTARTSYS)) { + struct io_waitid *iw = io_kiocb_to_cmd(req, struct io_waitid); + + /* Don't retry if cancel found it meanwhile */ + ret = -ECANCELED; + if (!(atomic_read(&iw->refs) & IO_WAITID_CANCEL_FLAG)) { + iw->head = ¤t->signal->wait_chldexit; + add_wait_queue(iw->head, &iwa->wo.child_wait); + ret = __do_wait(&iwa->wo); + if (ret == -ERESTARTSYS) { + /* retry armed, drop our ref */ + io_waitid_drop_issue_ref(req); + return; + } + + remove_wait_queue(iw->head, &iwa->wo.child_wait); + } + } + + io_waitid_complete(req, ret); +} + +static int io_waitid_wait(struct wait_queue_entry *wait, unsigned mode, + int sync, void *key) +{ + struct wait_opts *wo = container_of(wait, struct wait_opts, child_wait); + struct io_waitid_async *iwa = container_of(wo, struct io_waitid_async, wo); + struct io_kiocb *req = iwa->req; + struct io_waitid *iw = io_kiocb_to_cmd(req, struct io_waitid); + struct task_struct *p = key; + + if (!pid_child_should_wake(wo, p)) + return 0; + + /* cancel is in progress */ + if (atomic_fetch_inc(&iw->refs) & IO_WAITID_REF_MASK) + return 1; + + req->io_task_work.func = io_waitid_cb; + io_req_task_work_add(req); + list_del_init(&wait->entry); + return 1; +} + +int io_waitid_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_waitid *iw = io_kiocb_to_cmd(req, struct io_waitid); + + if (sqe->addr || sqe->buf_index || sqe->addr3 || sqe->waitid_flags) + return -EINVAL; + + iw->which = READ_ONCE(sqe->len); + iw->upid = READ_ONCE(sqe->fd); + iw->options = READ_ONCE(sqe->file_index); + iw->infop = u64_to_user_ptr(READ_ONCE(sqe->addr2)); + return 0; +} + +int io_waitid(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_waitid *iw = io_kiocb_to_cmd(req, struct io_waitid); + struct io_ring_ctx *ctx = req->ctx; + struct io_waitid_async *iwa; + int ret; + + if (io_alloc_async_data(req)) + return -ENOMEM; + + iwa = req->async_data; + iwa->req = req; + + ret = kernel_waitid_prepare(&iwa->wo, iw->which, iw->upid, &iw->info, + iw->options, NULL); + if (ret) + goto done; + + /* + * Mark the request as busy upfront, in case we're racing with the + * wakeup. If we are, then we'll notice when we drop this initial + * reference again after arming. + */ + atomic_set(&iw->refs, 1); + + /* + * Cancel must hold the ctx lock, so there's no risk of cancelation + * finding us until a) we remain on the list, and b) the lock is + * dropped. We only need to worry about racing with the wakeup + * callback. + */ + io_ring_submit_lock(ctx, issue_flags); + hlist_add_head(&req->hash_node, &ctx->waitid_list); + + init_waitqueue_func_entry(&iwa->wo.child_wait, io_waitid_wait); + iwa->wo.child_wait.private = req->task; + iw->head = ¤t->signal->wait_chldexit; + add_wait_queue(iw->head, &iwa->wo.child_wait); + + ret = __do_wait(&iwa->wo); + if (ret == -ERESTARTSYS) { + /* + * Nobody else grabbed a reference, it'll complete when we get + * a waitqueue callback, or if someone cancels it. + */ + if (!io_waitid_drop_issue_ref(req)) { + io_ring_submit_unlock(ctx, issue_flags); + return IOU_ISSUE_SKIP_COMPLETE; + } + + /* + * Wakeup triggered, racing with us. It was prevented from + * completing because of that, queue up the tw to do that. + */ + io_ring_submit_unlock(ctx, issue_flags); + return IOU_ISSUE_SKIP_COMPLETE; + } + + hlist_del_init(&req->hash_node); + remove_wait_queue(iw->head, &iwa->wo.child_wait); + ret = io_waitid_finish(req, ret); + + io_ring_submit_unlock(ctx, issue_flags); +done: + if (ret < 0) + req_set_fail(req); + io_req_set_res(req, ret, 0); + return IOU_OK; +} diff --git a/io_uring/waitid.h b/io_uring/waitid.h new file mode 100644 index 000000000000..956a8adafe8c --- /dev/null +++ b/io_uring/waitid.h @@ -0,0 +1,15 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "../kernel/exit.h" + +struct io_waitid_async { + struct io_kiocb *req; + struct wait_opts wo; +}; + +int io_waitid_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_waitid(struct io_kiocb *req, unsigned int issue_flags); +int io_waitid_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd, + unsigned int issue_flags); +bool io_waitid_remove_all(struct io_ring_ctx *ctx, struct task_struct *task, + bool cancel_all); |