diff options
| -rw-r--r-- | io_uring/filetable.c | 2 | ||||
| -rw-r--r-- | io_uring/io_uring.h | 9 | ||||
| -rw-r--r-- | io_uring/poll.c | 47 |
3 files changed, 47 insertions, 11 deletions
diff --git a/io_uring/filetable.c b/io_uring/filetable.c index 7b473259f3f4..68dfc6936aa7 100644 --- a/io_uring/filetable.c +++ b/io_uring/filetable.c @@ -101,8 +101,6 @@ static int io_install_fixed_file(struct io_ring_ctx *ctx, struct file *file, err: if (needs_switch) io_rsrc_node_switch(ctx, ctx->file_data); - if (ret) - fput(file); return ret; } diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h index cef5ff924e63..50bc3af44953 100644 --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -238,9 +238,14 @@ static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) static inline int io_run_task_work(void) { + /* + * Always check-and-clear the task_work notification signal. With how + * signaling works for task_work, we can find it set with nothing to + * run. We need to clear it for that case, like get_signal() does. + */ + if (test_thread_flag(TIF_NOTIFY_SIGNAL)) + clear_notify_signal(); if (task_work_pending(current)) { - if (test_thread_flag(TIF_NOTIFY_SIGNAL)) - clear_notify_signal(); __set_current_state(TASK_RUNNING); task_work_run(); return 1; diff --git a/io_uring/poll.c b/io_uring/poll.c index 055632e9092a..d9bf1767867e 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -40,7 +40,14 @@ struct io_poll_table { }; #define IO_POLL_CANCEL_FLAG BIT(31) -#define IO_POLL_REF_MASK GENMASK(30, 0) +#define IO_POLL_RETRY_FLAG BIT(30) +#define IO_POLL_REF_MASK GENMASK(29, 0) + +/* + * We usually have 1-2 refs taken, 128 is more than enough and we want to + * maximise the margin between this amount and the moment when it overflows. + */ +#define IO_POLL_REF_BIAS 128 #define IO_WQE_F_DOUBLE 1 @@ -58,6 +65,21 @@ static inline bool wqe_is_double(struct wait_queue_entry *wqe) return priv & IO_WQE_F_DOUBLE; } +static bool io_poll_get_ownership_slowpath(struct io_kiocb *req) +{ + int v; + + /* + * poll_refs are already elevated and we don't have much hope for + * grabbing the ownership. Instead of incrementing set a retry flag + * to notify the loop that there might have been some change. + */ + v = atomic_fetch_or(IO_POLL_RETRY_FLAG, &req->poll_refs); + if (v & IO_POLL_REF_MASK) + return false; + return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK); +} + /* * If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can * bump it and acquire ownership. It's disallowed to modify requests while not @@ -66,6 +88,8 @@ static inline bool wqe_is_double(struct wait_queue_entry *wqe) */ static inline bool io_poll_get_ownership(struct io_kiocb *req) { + if (unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS)) + return io_poll_get_ownership_slowpath(req); return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK); } @@ -235,6 +259,16 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked) */ if ((v & IO_POLL_REF_MASK) != 1) req->cqe.res = 0; + if (v & IO_POLL_RETRY_FLAG) { + req->cqe.res = 0; + /* + * We won't find new events that came in between + * vfs_poll and the ref put unless we clear the flag + * in advance. + */ + atomic_andnot(IO_POLL_RETRY_FLAG, &req->poll_refs); + v &= ~IO_POLL_RETRY_FLAG; + } /* the mask was stashed in __io_poll_execute */ if (!req->cqe.res) { @@ -274,7 +308,8 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked) * Release all references, retry if someone tried to restart * task_work while we were executing it. */ - } while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs)); + } while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs) & + IO_POLL_REF_MASK); return IOU_POLL_NO_ACTION; } @@ -518,7 +553,6 @@ static int __io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) { struct io_ring_ctx *ctx = req->ctx; - int v; INIT_HLIST_NODE(&req->hash_node); req->work.cancel_seq = atomic_read(&ctx->cancel_seq); @@ -586,11 +620,10 @@ static int __io_arm_poll_handler(struct io_kiocb *req, if (ipt->owning) { /* - * Release ownership. If someone tried to queue a tw while it was - * locked, kick it off for them. + * Try to release ownership. If we see a change of state, e.g. + * poll was waken up, queue up a tw, it'll deal with it. */ - v = atomic_dec_return(&req->poll_refs); - if (unlikely(v & IO_POLL_REF_MASK)) + if (atomic_cmpxchg(&req->poll_refs, 1, 0) != 1) __io_poll_execute(req, 0); } return 0; |