From 4e88d6e7793f2f445f43bd608828541d7f43b608 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 7 Dec 2019 20:59:47 -0700 Subject: [PATCH 01/11] io_uring: allow unbreakable links MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some commands will invariably end in a failure in the sense that the completion result will be less than zero. One such example is timeouts that don't have a completion count set, they will always complete with -ETIME unless cancelled. For linked commands, we sever links and fail the rest of the chain if the result is less than zero. Since we have commands where we know that will happen, add IOSQE_IO_HARDLINK as a stronger link that doesn't sever regardless of the completion result. Note that the link will still sever if we fail submitting the parent request, hard links are only resilient in the presence of completion results for requests that did submit correctly. Cc: stable@vger.kernel.org # v5.4 Reviewed-by: Pavel Begunkov Reported-by: 李通洲 Signed-off-by: Jens Axboe --- fs/io_uring.c | 84 +++++++++++++++++++---------------- include/uapi/linux/io_uring.h | 1 + 2 files changed, 47 insertions(+), 38 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 405be10da73d..040e6c11ff37 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -377,6 +377,7 @@ struct io_kiocb { #define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */ #define REQ_F_INFLIGHT 16384 /* on inflight list */ #define REQ_F_COMP_LOCKED 32768 /* completion under lock */ +#define REQ_F_HARDLINK 65536 /* doesn't sever on completion < 0 */ u64 user_data; u32 result; u32 sequence; @@ -1292,6 +1293,12 @@ static void kiocb_end_write(struct io_kiocb *req) file_end_write(req->file); } +static inline void req_set_fail_links(struct io_kiocb *req) +{ + if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK) + req->flags |= REQ_F_FAIL_LINK; +} + static void io_complete_rw_common(struct kiocb *kiocb, long res) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); @@ -1299,8 +1306,8 @@ static void io_complete_rw_common(struct kiocb *kiocb, long res) if (kiocb->ki_flags & IOCB_WRITE) kiocb_end_write(req); - if ((req->flags & REQ_F_LINK) && res != req->result) - req->flags |= REQ_F_FAIL_LINK; + if (res != req->result) + req_set_fail_links(req); io_cqring_add_event(req, res); } @@ -1330,8 +1337,8 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2) if (kiocb->ki_flags & IOCB_WRITE) kiocb_end_write(req); - if ((req->flags & REQ_F_LINK) && res != req->result) - req->flags |= REQ_F_FAIL_LINK; + if (res != req->result) + req_set_fail_links(req); req->result = res; if (res != -EAGAIN) req->flags |= REQ_F_IOPOLL_COMPLETED; @@ -1956,8 +1963,8 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, end > 0 ? end : LLONG_MAX, fsync_flags & IORING_FSYNC_DATASYNC); - if (ret < 0 && (req->flags & REQ_F_LINK)) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; @@ -2003,8 +2010,8 @@ static int io_sync_file_range(struct io_kiocb *req, ret = sync_file_range(req->rw.ki_filp, sqe_off, sqe_len, flags); - if (ret < 0 && (req->flags & REQ_F_LINK)) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; @@ -2079,8 +2086,8 @@ static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, out: io_cqring_add_event(req, ret); - if (ret < 0 && (req->flags & REQ_F_LINK)) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_put_req_find_next(req, nxt); return 0; #else @@ -2161,8 +2168,8 @@ static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, out: io_cqring_add_event(req, ret); - if (ret < 0 && (req->flags & REQ_F_LINK)) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_put_req_find_next(req, nxt); return 0; #else @@ -2196,8 +2203,8 @@ static int io_accept(struct io_kiocb *req, const struct io_uring_sqe *sqe, } if (ret == -ERESTARTSYS) ret = -EINTR; - if (ret < 0 && (req->flags & REQ_F_LINK)) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; @@ -2263,8 +2270,8 @@ static int io_connect(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (ret == -ERESTARTSYS) ret = -EINTR; out: - if (ret < 0 && (req->flags & REQ_F_LINK)) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; @@ -2340,8 +2347,8 @@ static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe) spin_unlock_irq(&ctx->completion_lock); io_cqring_add_event(req, ret); - if (ret < 0 && (req->flags & REQ_F_LINK)) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_put_req(req); return 0; } @@ -2399,8 +2406,8 @@ static void io_poll_complete_work(struct io_wq_work **workptr) io_cqring_ev_posted(ctx); - if (ret < 0 && req->flags & REQ_F_LINK) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_put_req_find_next(req, &nxt); if (nxt) *workptr = &nxt->work; @@ -2582,8 +2589,7 @@ static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); - if (req->flags & REQ_F_LINK) - req->flags |= REQ_F_FAIL_LINK; + req_set_fail_links(req); io_put_req(req); return HRTIMER_NORESTART; } @@ -2608,8 +2614,7 @@ static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data) if (ret == -1) return -EALREADY; - if (req->flags & REQ_F_LINK) - req->flags |= REQ_F_FAIL_LINK; + req_set_fail_links(req); io_cqring_fill_event(req, -ECANCELED); io_put_req(req); return 0; @@ -2640,8 +2645,8 @@ static int io_timeout_remove(struct io_kiocb *req, io_commit_cqring(ctx); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); - if (ret < 0 && req->flags & REQ_F_LINK) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_put_req(req); return 0; } @@ -2822,8 +2827,8 @@ done: spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); - if (ret < 0 && (req->flags & REQ_F_LINK)) - req->flags |= REQ_F_FAIL_LINK; + if (ret < 0) + req_set_fail_links(req); io_put_req_find_next(req, nxt); } @@ -3044,8 +3049,7 @@ static void io_wq_submit_work(struct io_wq_work **workptr) io_put_req(req); if (ret) { - if (req->flags & REQ_F_LINK) - req->flags |= REQ_F_FAIL_LINK; + req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req(req); } @@ -3179,8 +3183,7 @@ static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer) spin_unlock_irqrestore(&ctx->completion_lock, flags); if (prev) { - if (prev->flags & REQ_F_LINK) - prev->flags |= REQ_F_FAIL_LINK; + req_set_fail_links(prev); io_async_find_and_cancel(ctx, req, prev->user_data, NULL, -ETIME); io_put_req(prev); @@ -3273,8 +3276,7 @@ err: /* and drop final reference, if we failed */ if (ret) { io_cqring_add_event(req, ret); - if (req->flags & REQ_F_LINK) - req->flags |= REQ_F_FAIL_LINK; + req_set_fail_links(req); io_put_req(req); } } @@ -3293,8 +3295,7 @@ static void io_queue_sqe(struct io_kiocb *req) if (ret) { if (ret != -EIOCBQUEUED) { io_cqring_add_event(req, ret); - if (req->flags & REQ_F_LINK) - req->flags |= REQ_F_FAIL_LINK; + req_set_fail_links(req); io_double_put_req(req); } } else @@ -3311,7 +3312,8 @@ static inline void io_queue_link_head(struct io_kiocb *req) } -#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK) +#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \ + IOSQE_IO_HARDLINK) static bool io_submit_sqe(struct io_kiocb *req, struct io_submit_state *state, struct io_kiocb **link) @@ -3349,6 +3351,9 @@ err_req: if (req->sqe->flags & IOSQE_IO_DRAIN) (*link)->flags |= REQ_F_DRAIN_LINK | REQ_F_IO_DRAIN; + if (req->sqe->flags & IOSQE_IO_HARDLINK) + req->flags |= REQ_F_HARDLINK; + io = kmalloc(sizeof(*io), GFP_KERNEL); if (!io) { ret = -EAGAIN; @@ -3358,13 +3363,16 @@ err_req: ret = io_req_defer_prep(req, io); if (ret) { kfree(io); + /* fail even hard links since we don't submit */ prev->flags |= REQ_F_FAIL_LINK; goto err_req; } trace_io_uring_link(ctx, req, prev); list_add_tail(&req->link_list, &prev->link_list); - } else if (req->sqe->flags & IOSQE_IO_LINK) { + } else if (req->sqe->flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) { req->flags |= REQ_F_LINK; + if (req->sqe->flags & IOSQE_IO_HARDLINK) + req->flags |= REQ_F_HARDLINK; INIT_LIST_HEAD(&req->link_list); *link = req; diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index eabccb46edd1..ea231366f5fd 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -48,6 +48,7 @@ struct io_uring_sqe { #define IOSQE_FIXED_FILE (1U << 0) /* use fixed fileset */ #define IOSQE_IO_DRAIN (1U << 1) /* issue after inflight IO */ #define IOSQE_IO_LINK (1U << 2) /* links next sqe */ +#define IOSQE_IO_HARDLINK (1U << 3) /* like LINK, but stronger */ /* * io_uring_setup() flags From 506d95ff5d6aa0a099a116c49d3884e29801d843 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 7 Dec 2019 21:03:59 -0700 Subject: [PATCH 02/11] io-wq: remove worker->wait waitqueue We only have one cases of using the waitqueue to wake the worker, the rest are using wake_up_process(). Since we can save some cycles not fiddling with the waitqueue io_wqe_worker(), switch the work activation to task wakeup and get rid of the now unused wait_queue_head_t in struct io_worker. Signed-off-by: Jens Axboe --- fs/io-wq.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/fs/io-wq.c b/fs/io-wq.c index 74b40506c5d9..6b663ddceb42 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -49,7 +49,6 @@ struct io_worker { struct hlist_nulls_node nulls_node; struct list_head all_list; struct task_struct *task; - wait_queue_head_t wait; struct io_wqe *wqe; struct io_wq_work *cur_work; @@ -258,7 +257,7 @@ static bool io_wqe_activate_free_worker(struct io_wqe *wqe) worker = hlist_nulls_entry(n, struct io_worker, nulls_node); if (io_worker_get(worker)) { - wake_up(&worker->wait); + wake_up_process(worker->task); io_worker_release(worker); return true; } @@ -497,13 +496,11 @@ static int io_wqe_worker(void *data) struct io_worker *worker = data; 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); - + set_current_state(TASK_INTERRUPTIBLE); spin_lock_irq(&wqe->lock); if (io_wqe_run_queue(wqe)) { __set_current_state(TASK_RUNNING); @@ -526,8 +523,6 @@ static int io_wqe_worker(void *data) break; } - finish_wait(&worker->wait, &wait); - if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) { spin_lock_irq(&wqe->lock); if (!wq_list_empty(&wqe->work_list)) @@ -589,7 +584,6 @@ static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index) refcount_set(&worker->ref, 1); worker->nulls_node.pprev = NULL; - init_waitqueue_head(&worker->wait); worker->wqe = wqe; spin_lock_init(&worker->lock); From e995d5123ed433e37a8d63ac528737c912592e3d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 7 Dec 2019 21:06:46 -0700 Subject: [PATCH 03/11] io-wq: briefly spin for new work after finishing work To avoid going to sleep only to get woken shortly thereafter, spin briefly for new work upon completion of work. Signed-off-by: Jens Axboe --- fs/io-wq.c | 24 ++++++++++++++++++++++-- fs/io-wq.h | 7 ++++--- 2 files changed, 26 insertions(+), 5 deletions(-) diff --git a/fs/io-wq.c b/fs/io-wq.c index 6b663ddceb42..90c4978781fb 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -491,26 +491,46 @@ next: } while (1); } +static inline void io_worker_spin_for_work(struct io_wqe *wqe) +{ + int i = 0; + + while (++i < 1000) { + if (io_wqe_run_queue(wqe)) + break; + if (need_resched()) + break; + cpu_relax(); + } +} + static int io_wqe_worker(void *data) { struct io_worker *worker = data; struct io_wqe *wqe = worker->wqe; struct io_wq *wq = wqe->wq; + bool did_work; io_worker_start(wqe, worker); + did_work = false; while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) { set_current_state(TASK_INTERRUPTIBLE); +loop: + if (did_work) + io_worker_spin_for_work(wqe); spin_lock_irq(&wqe->lock); if (io_wqe_run_queue(wqe)) { __set_current_state(TASK_RUNNING); io_worker_handle_work(worker); - continue; + did_work = true; + goto loop; } + did_work = false; /* drops the lock on success, retry */ if (__io_worker_idle(wqe, worker)) { __release(&wqe->lock); - continue; + goto loop; } spin_unlock_irq(&wqe->lock); if (signal_pending(current)) diff --git a/fs/io-wq.h b/fs/io-wq.h index 7c333a28e2a7..fb993b2bd0ef 100644 --- a/fs/io-wq.h +++ b/fs/io-wq.h @@ -35,7 +35,8 @@ static inline void wq_list_add_tail(struct io_wq_work_node *node, struct io_wq_work_list *list) { if (!list->first) { - list->first = list->last = node; + list->last = node; + WRITE_ONCE(list->first, node); } else { list->last->next = node; list->last = node; @@ -47,7 +48,7 @@ static inline void wq_node_del(struct io_wq_work_list *list, struct io_wq_work_node *prev) { if (node == list->first) - list->first = node->next; + WRITE_ONCE(list->first, node->next); if (node == list->last) list->last = prev; if (prev) @@ -58,7 +59,7 @@ static inline void wq_node_del(struct io_wq_work_list *list, #define wq_list_for_each(pos, prv, head) \ for (pos = (head)->first, prv = NULL; pos; prv = pos, pos = (pos)->next) -#define wq_list_empty(list) ((list)->first == NULL) +#define wq_list_empty(list) (READ_ONCE((list)->first) == NULL) #define INIT_WQ_LIST(list) do { \ (list)->first = NULL; \ (list)->last = NULL; \ From 8a4955ff1cca7d4da480774034a16e7c28bafec8 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 9 Dec 2019 14:52:35 -0700 Subject: [PATCH 04/11] io_uring: sqthread should grab ctx->uring_lock for submissions We use the mutex to guard against registered file updates, for instance. Ensure we're safe in accessing that state against concurrent updates. Signed-off-by: Jens Axboe --- fs/io_uring.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 040e6c11ff37..366fc351869d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2996,12 +2996,7 @@ static int io_issue_sqe(struct io_kiocb *req, struct io_kiocb **nxt, if (req->result == -EAGAIN) return -EAGAIN; - /* workqueue context doesn't hold uring_lock, grab it now */ - if (req->in_async) - mutex_lock(&ctx->uring_lock); io_iopoll_req_issued(req); - if (req->in_async) - mutex_unlock(&ctx->uring_lock); } return 0; @@ -3655,7 +3650,9 @@ static int io_sq_thread(void *data) } to_submit = min(to_submit, ctx->sq_entries); + mutex_lock(&ctx->uring_lock); ret = io_submit_sqes(ctx, to_submit, NULL, -1, &cur_mm, true); + mutex_unlock(&ctx->uring_lock); if (ret > 0) inflight += ret; } From d96885658d9971fc2c752b8699f17a42ef745db6 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 9 Dec 2019 19:35:20 -0700 Subject: [PATCH 05/11] io_uring: deferred send/recvmsg should assign iov Don't just assign it from the main call path, that can miss the case when we're called from issue deferral. Signed-off-by: Jens Axboe --- fs/io_uring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 366fc351869d..b84def504201 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2026,6 +2026,7 @@ static int io_sendmsg_prep(struct io_kiocb *req, struct io_async_ctx *io) flags = READ_ONCE(sqe->msg_flags); msg = (struct user_msghdr __user *)(unsigned long) READ_ONCE(sqe->addr); + io->msg.iov = io->msg.fast_iov; return sendmsg_copy_msghdr(&io->msg.msg, msg, flags, &io->msg.iov); #else return 0; @@ -2061,7 +2062,6 @@ static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, } else { kmsg = &io.msg.msg; kmsg->msg_name = &addr; - io.msg.iov = io.msg.fast_iov; ret = io_sendmsg_prep(req, &io); if (ret) goto out; @@ -2104,6 +2104,7 @@ static int io_recvmsg_prep(struct io_kiocb *req, struct io_async_ctx *io) flags = READ_ONCE(sqe->msg_flags); msg = (struct user_msghdr __user *)(unsigned long) READ_ONCE(sqe->addr); + io->msg.iov = io->msg.fast_iov; return recvmsg_copy_msghdr(&io->msg.msg, msg, flags, &io->msg.uaddr, &io->msg.iov); #else @@ -2143,7 +2144,6 @@ static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, } else { kmsg = &io.msg.msg; kmsg->msg_name = &addr; - io.msg.iov = io.msg.fast_iov; ret = io_recvmsg_prep(req, &io); if (ret) goto out; From 392edb45b24337eaa0bc1ecd4e3cf897e662ec61 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 9 Dec 2019 17:52:20 -0700 Subject: [PATCH 06/11] io_uring: don't dynamically allocate poll data This essentially reverts commit e944475e6984. For high poll ops workloads, like TAO, the dynamic allocation of the wait_queue entry for IORING_OP_POLL_ADD adds considerable extra overhead. Go back to embedding the wait_queue_entry, but keep the usage of wait->private for the pointer stashing. Signed-off-by: Jens Axboe --- fs/io_uring.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index b84def504201..89a2c8b4f8fb 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -293,7 +293,7 @@ struct io_poll_iocb { __poll_t events; bool done; bool canceled; - struct wait_queue_entry *wait; + struct wait_queue_entry wait; }; struct io_timeout_data { @@ -2286,8 +2286,8 @@ static void io_poll_remove_one(struct io_kiocb *req) spin_lock(&poll->head->lock); WRITE_ONCE(poll->canceled, true); - if (!list_empty(&poll->wait->entry)) { - list_del_init(&poll->wait->entry); + if (!list_empty(&poll->wait.entry)) { + list_del_init(&poll->wait.entry); io_queue_async_work(req); } spin_unlock(&poll->head->lock); @@ -2358,7 +2358,6 @@ static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error) struct io_ring_ctx *ctx = req->ctx; req->poll.done = true; - kfree(req->poll.wait); if (error) io_cqring_fill_event(req, error); else @@ -2396,7 +2395,7 @@ static void io_poll_complete_work(struct io_wq_work **workptr) */ spin_lock_irq(&ctx->completion_lock); if (!mask && ret != -ECANCELED) { - add_wait_queue(poll->head, poll->wait); + add_wait_queue(poll->head, &poll->wait); spin_unlock_irq(&ctx->completion_lock); return; } @@ -2426,7 +2425,7 @@ static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, if (mask && !(mask & poll->events)) return 0; - list_del_init(&poll->wait->entry); + list_del_init(&poll->wait.entry); /* * Run completion inline if we can. We're using trylock here because @@ -2467,7 +2466,7 @@ static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, pt->error = 0; pt->req->poll.head = head; - add_wait_queue(head, pt->req->poll.wait); + add_wait_queue(head, &pt->req->poll.wait); } static void io_poll_req_insert(struct io_kiocb *req) @@ -2496,10 +2495,6 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (!poll->file) return -EBADF; - poll->wait = kmalloc(sizeof(*poll->wait), GFP_KERNEL); - if (!poll->wait) - return -ENOMEM; - req->io = NULL; INIT_IO_WORK(&req->work, io_poll_complete_work); events = READ_ONCE(sqe->poll_events); @@ -2516,9 +2511,9 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe, ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */ /* initialized the list so that we can do list_empty checks */ - INIT_LIST_HEAD(&poll->wait->entry); - init_waitqueue_func_entry(poll->wait, io_poll_wake); - poll->wait->private = poll; + INIT_LIST_HEAD(&poll->wait.entry); + init_waitqueue_func_entry(&poll->wait, io_poll_wake); + poll->wait.private = poll; INIT_LIST_HEAD(&req->list); @@ -2527,14 +2522,14 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe, spin_lock_irq(&ctx->completion_lock); if (likely(poll->head)) { spin_lock(&poll->head->lock); - if (unlikely(list_empty(&poll->wait->entry))) { + if (unlikely(list_empty(&poll->wait.entry))) { if (ipt.error) cancel = true; ipt.error = 0; mask = 0; } if (mask || ipt.error) - list_del_init(&poll->wait->entry); + list_del_init(&poll->wait.entry); else if (cancel) WRITE_ONCE(poll->canceled, true); else if (!poll->done) /* actually waiting for an event */ From 4a0a7a187453e65bdd24b9ede045b4c36b958868 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 9 Dec 2019 20:01:01 -0700 Subject: [PATCH 07/11] io_uring: run next sqe inline if possible One major use case of linked commands is the ability to run the next link inline, if at all possible. This is done correctly for async offload, but somewhere along the line we lost the ability to do so when we were able to complete a request without having to punt it. Ensure that we do so correctly. Signed-off-by: Jens Axboe --- fs/io_uring.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 89a2c8b4f8fb..3dae005bfb56 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3224,13 +3224,14 @@ static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req) static void __io_queue_sqe(struct io_kiocb *req) { - struct io_kiocb *linked_timeout = io_prep_linked_timeout(req); + struct io_kiocb *linked_timeout; struct io_kiocb *nxt = NULL; int ret; +again: + linked_timeout = io_prep_linked_timeout(req); + ret = io_issue_sqe(req, &nxt, true); - if (nxt) - io_queue_async_work(nxt); /* * We async punt it if the file wasn't marked NOWAIT, or if the file @@ -3249,7 +3250,7 @@ static void __io_queue_sqe(struct io_kiocb *req) * submit reference when the iocb is actually submitted. */ io_queue_async_work(req); - return; + goto done_req; } err: @@ -3269,6 +3270,12 @@ err: req_set_fail_links(req); io_put_req(req); } +done_req: + if (nxt) { + req = nxt; + nxt = NULL; + goto again; + } } static void io_queue_sqe(struct io_kiocb *req) From 53108d476a105ab2597d7a4e6040b127829391b5 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 9 Dec 2019 20:12:38 -0700 Subject: [PATCH 08/11] io_uring: only hash regular files for async work execution We hash regular files to avoid having multiple threads hammer on the inode mutex, but it should not be needed on other types of files (like sockets). Signed-off-by: Jens Axboe --- fs/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 3dae005bfb56..e54bd469d53a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -581,7 +581,9 @@ static inline bool io_prep_async_work(struct io_kiocb *req, switch (req->sqe->opcode) { case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: - do_hashed = true; + /* only regular files should be hashed for writes */ + if (req->flags & REQ_F_ISREG) + do_hashed = true; /* fall-through */ case IORING_OP_READV: case IORING_OP_READ_FIXED: From ebfcd8955c0b52eb793bcbc9e71140e3d0cdb228 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 9 Dec 2019 20:58:56 -0700 Subject: [PATCH 09/11] net: make socket read/write_iter() honor IOCB_NOWAIT The socket read/write helpers only look at the file O_NONBLOCK. not the iocb IOCB_NOWAIT flag. This breaks users like preadv2/pwritev2 and io_uring that rely on not having the file itself marked nonblocking, but rather the iocb itself. Cc: netdev@vger.kernel.org Acked-by: David Miller Signed-off-by: Jens Axboe --- net/socket.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/socket.c b/net/socket.c index b343db1489bd..b116e58d6438 100644 --- a/net/socket.c +++ b/net/socket.c @@ -957,7 +957,7 @@ static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to) .msg_iocb = iocb}; ssize_t res; - if (file->f_flags & O_NONBLOCK) + if (file->f_flags & O_NONBLOCK || (iocb->ki_flags & IOCB_NOWAIT)) msg.msg_flags = MSG_DONTWAIT; if (iocb->ki_pos != 0) @@ -982,7 +982,7 @@ static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from) if (iocb->ki_pos != 0) return -ESPIPE; - if (file->f_flags & O_NONBLOCK) + if (file->f_flags & O_NONBLOCK || (iocb->ki_flags & IOCB_NOWAIT)) msg.msg_flags = MSG_DONTWAIT; if (sock->type == SOCK_SEQPACKET) From 10d59345578a116042c1a5d737a18234aaf3e0e6 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 9 Dec 2019 20:16:22 -0700 Subject: [PATCH 10/11] io_uring: add sockets to list of files that support non-blocking issue In chasing a performance issue between using IORING_OP_RECVMSG and IORING_OP_READV on sockets, tracing showed that we always punt the socket reads to async offload. This is due to io_file_supports_async() not checking for S_ISSOCK on the inode. Since sockets supports the O_NONBLOCK (or MSG_DONTWAIT) flag just fine, add sockets to the list of file types that we can do a non-blocking issue to. Signed-off-by: Jens Axboe --- fs/io_uring.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index e54bd469d53a..42de210be631 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1431,7 +1431,7 @@ static bool io_file_supports_async(struct file *file) { umode_t mode = file_inode(file)->i_mode; - if (S_ISBLK(mode) || S_ISCHR(mode)) + if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISSOCK(mode)) return true; if (S_ISREG(mode) && file->f_op != &io_uring_fops) return true; @@ -1867,7 +1867,9 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt, goto copy_iov; } - if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) + /* file path doesn't support NOWAIT for non-direct_IO */ + if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) && + (req->flags & REQ_F_ISREG)) goto copy_iov; iov_count = iov_iter_count(&iter); From 9e3aa61ae3e01ce1ce6361a41ef725e1f4d1d2bf Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 11 Dec 2019 15:55:43 -0700 Subject: [PATCH 11/11] io_uring: ensure we return -EINVAL on unknown opcode If we submit an unknown opcode and have fd == -1, io_op_needs_file() will return true as we default to needing a file. Then when we go and assign the file, we find the 'fd' invalid and return -EBADF. We really should be returning -EINVAL for that case, as we normally do for unsupported opcodes. Change io_op_needs_file() to have the following return values: 0 - does not need a file 1 - does need a file < 0 - error value and use this to pass back the right value for this invalid case. Signed-off-by: Jens Axboe --- fs/io_uring.c | 21 ++++++++++++------- include/uapi/linux/io_uring.h | 39 ++++++++++++++++++++--------------- 2 files changed, 36 insertions(+), 24 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 42de210be631..9b1833fedc5c 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3062,7 +3062,12 @@ static void io_wq_submit_work(struct io_wq_work **workptr) } } -static bool io_op_needs_file(const struct io_uring_sqe *sqe) +static bool io_req_op_valid(int op) +{ + return op >= IORING_OP_NOP && op < IORING_OP_LAST; +} + +static int io_op_needs_file(const struct io_uring_sqe *sqe) { int op = READ_ONCE(sqe->opcode); @@ -3073,9 +3078,11 @@ static bool io_op_needs_file(const struct io_uring_sqe *sqe) case IORING_OP_TIMEOUT_REMOVE: case IORING_OP_ASYNC_CANCEL: case IORING_OP_LINK_TIMEOUT: - return false; + return 0; default: - return true; + if (io_req_op_valid(op)) + return 1; + return -EINVAL; } } @@ -3092,7 +3099,7 @@ static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; unsigned flags; - int fd; + int fd, ret; flags = READ_ONCE(req->sqe->flags); fd = READ_ONCE(req->sqe->fd); @@ -3100,8 +3107,9 @@ static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req) if (flags & IOSQE_IO_DRAIN) req->flags |= REQ_F_IO_DRAIN; - if (!io_op_needs_file(req->sqe)) - return 0; + ret = io_op_needs_file(req->sqe); + if (ret <= 0) + return ret; if (flags & IOSQE_FIXED_FILE) { if (unlikely(!ctx->file_table || @@ -3312,7 +3320,6 @@ static inline void io_queue_link_head(struct io_kiocb *req) io_queue_sqe(req); } - #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \ IOSQE_IO_HARDLINK) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index ea231366f5fd..a3300e1b9a01 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -58,23 +58,28 @@ struct io_uring_sqe { #define IORING_SETUP_SQ_AFF (1U << 2) /* sq_thread_cpu is valid */ #define IORING_SETUP_CQSIZE (1U << 3) /* app defines CQ size */ -#define IORING_OP_NOP 0 -#define IORING_OP_READV 1 -#define IORING_OP_WRITEV 2 -#define IORING_OP_FSYNC 3 -#define IORING_OP_READ_FIXED 4 -#define IORING_OP_WRITE_FIXED 5 -#define IORING_OP_POLL_ADD 6 -#define IORING_OP_POLL_REMOVE 7 -#define IORING_OP_SYNC_FILE_RANGE 8 -#define IORING_OP_SENDMSG 9 -#define IORING_OP_RECVMSG 10 -#define IORING_OP_TIMEOUT 11 -#define IORING_OP_TIMEOUT_REMOVE 12 -#define IORING_OP_ACCEPT 13 -#define IORING_OP_ASYNC_CANCEL 14 -#define IORING_OP_LINK_TIMEOUT 15 -#define IORING_OP_CONNECT 16 +enum { + IORING_OP_NOP, + IORING_OP_READV, + IORING_OP_WRITEV, + IORING_OP_FSYNC, + IORING_OP_READ_FIXED, + IORING_OP_WRITE_FIXED, + IORING_OP_POLL_ADD, + IORING_OP_POLL_REMOVE, + IORING_OP_SYNC_FILE_RANGE, + IORING_OP_SENDMSG, + IORING_OP_RECVMSG, + IORING_OP_TIMEOUT, + IORING_OP_TIMEOUT_REMOVE, + IORING_OP_ACCEPT, + IORING_OP_ASYNC_CANCEL, + IORING_OP_LINK_TIMEOUT, + IORING_OP_CONNECT, + + /* this goes last, obviously */ + IORING_OP_LAST, +}; /* * sqe->fsync_flags