From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C629C433EF for ; Fri, 27 May 2022 16:59:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243542AbiE0Q7x (ORCPT ); Fri, 27 May 2022 12:59:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240823AbiE0Q7w (ORCPT ); Fri, 27 May 2022 12:59:52 -0400 Received: from mail-il1-x12b.google.com (mail-il1-x12b.google.com [IPv6:2607:f8b0:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5905122B57 for ; Fri, 27 May 2022 09:59:50 -0700 (PDT) Received: by mail-il1-x12b.google.com with SMTP id j15so3469674ilo.5 for ; Fri, 27 May 2022 09:59:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:content-language:to:from :subject:cc:content-transfer-encoding; bh=P99tpbGRsmjzVaw5Qg8oN9jqoiIKjuvZTVLQshwhi7c=; b=7J9qcNvvM82ulQtnSOtqC0tEsCZPuPeoomTJZp5PbWEFP3/eQr+M2v5hxoCmqG1gqG 0gJ8Qag7M0Sgg5zi+xSKo2MHPXtFlYzgZZG87s5ZaHimNCNMPxNgZMJtAnSCkELZ5aEH VzaRxTVwOn2ODK4wXSP7XNg2CLLeqfTOxCE36yxx0GeHpWRX9ZJNKzN87id4xsKvx41+ 4CIqeYn35vNv9aH8+QZ+/gOBhYCm8WpvIys8YKHdxYYanodOl+yEGIotkZrtR0lONKe2 sGLPh858qljq5AGMGsidcxAxEIQEWDxdsiHEbuDeoGAAZABeKFUwNSEf9evwPUn21Vgg GN6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent :content-language:to:from:subject:cc:content-transfer-encoding; bh=P99tpbGRsmjzVaw5Qg8oN9jqoiIKjuvZTVLQshwhi7c=; b=cDVfCiFYQEg+XGlMrGADvte8L/GXMZjk/Ul95bxuvP/mVBSjcLBMjnAlsTfZs1184+ FO0IEF+0SXuKVjIq4kfjSauUSxugUQs4D+RuC2iJmVuid5QvZHcgf8CyquyzbxTk4p6I yskRATwLiaphHBSCDDjOVl00OZUkAYxOMr5U4Ju3j4U5lp0gaynj1D4zkBRvbUZ590tu YrXXiJqd40K/eX48x17wAdccDg9N9tyujaholiwFkBySAeEWl7ALOImqfP9DHX09c24v PQW+M7eh7v2fBS04fPJwVcP1bydxi7MVr4rBf6KwvKduD8AbnPVNOa/NcRMU/hkgRxyM kstw== X-Gm-Message-State: AOAM532J6+gVC4/mNx0TQbfAz4w0NDFnoqvpOVPJwvOrjt6Snwog7w2I bpsid2nQWi7vmZ5LyCAC/oH2ehEBgX++ig== X-Google-Smtp-Source: ABdhPJx2HqR6aSwfpxcIMytWA+0tlELA2UBh1j4K83OpCwNEmJCY9uGtbZfINPEvrbKxXPLe7MYuJg== X-Received: by 2002:a92:2c11:0:b0:2d0:e874:636 with SMTP id t17-20020a922c11000000b002d0e8740636mr22967562ile.318.1653670789981; Fri, 27 May 2022 09:59:49 -0700 (PDT) Received: from [192.168.1.172] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id b18-20020a92a052000000b002cc20b48163sm1427763ilm.3.2022.05.27.09.59.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 27 May 2022 09:59:49 -0700 (PDT) Message-ID: Date: Fri, 27 May 2022 10:59:48 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Content-Language: en-US To: io-uring From: Jens Axboe Subject: [PATCH RFC -next] io_uring: add support for level triggered poll Cc: Pavel Begunkov Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org By default, the POLL_ADD command does edge triggered poll - if we get a non-zero mask on the initial poll attempt, we complete the request successfully. Support level triggered by always waiting for a notification, regardless of whether or not the initial mask matches the file state. Signed-off-by: Jens Axboe --- Wrote a test case and it seems to work as it should, and the usual regressions pass as well. diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 53e7dae92e42..1d176f935f5d 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -226,10 +226,13 @@ enum io_uring_op { * * IORING_POLL_UPDATE Update existing poll request, matching * sqe->addr as the old user_data field. + * + * IORING_POLL_LEVEL Level triggered poll. */ #define IORING_POLL_ADD_MULTI (1U << 0) #define IORING_POLL_UPDATE_EVENTS (1U << 1) #define IORING_POLL_UPDATE_USER_DATA (1U << 2) +#define IORING_POLL_ADD_LEVEL (1U << 3) /* * ASYNC_CANCEL flags. diff --git a/io_uring/poll.c b/io_uring/poll.c index ed9f74403d89..7a98d934428e 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -425,11 +425,13 @@ static int __io_arm_poll_handler(struct io_kiocb *req, atomic_set(&req->poll_refs, 1); mask = vfs_poll(req->file, &ipt->pt) & poll->events; - if (mask && (poll->events & EPOLLONESHOT)) { + if (mask && + ((poll->events & (EPOLLET|EPOLLONESHOT)) == (EPOLLET|EPOLLONESHOT))) { io_poll_remove_entries(req); /* no one else has access to the req, forget about the ref */ return mask; } + if (!mask && unlikely(ipt->error || !ipt->nr_entries)) { io_poll_remove_entries(req); if (!ipt->error) @@ -441,7 +443,7 @@ static int __io_arm_poll_handler(struct io_kiocb *req, io_poll_req_insert(req); spin_unlock(&ctx->completion_lock); - if (mask) { + if (mask && (poll->events & EPOLLET)) { /* can't multishot if failed, just queue the event we've got */ if (unlikely(ipt->error || !ipt->nr_entries)) poll->events |= EPOLLONESHOT; @@ -474,7 +476,7 @@ int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) struct io_ring_ctx *ctx = req->ctx; struct async_poll *apoll; struct io_poll_table ipt; - __poll_t mask = POLLPRI | POLLERR; + __poll_t mask = POLLPRI | POLLERR | EPOLLET; int ret; if (!def->pollin && !def->pollout) @@ -636,7 +638,10 @@ static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe, #endif if (!(flags & IORING_POLL_ADD_MULTI)) events |= EPOLLONESHOT; - return demangle_poll(events) | (events & (EPOLLEXCLUSIVE|EPOLLONESHOT)); + if (!(flags & IORING_POLL_ADD_LEVEL)) + events |= EPOLLET; + return demangle_poll(events) | + (events & (EPOLLEXCLUSIVE|EPOLLONESHOT|EPOLLET)); } int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) @@ -677,7 +682,7 @@ int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) if (sqe->buf_index || sqe->off || sqe->addr) return -EINVAL; flags = READ_ONCE(sqe->len); - if (flags & ~IORING_POLL_ADD_MULTI) + if (flags & ~(IORING_POLL_ADD_MULTI|IORING_POLL_ADD_LEVEL)) return -EINVAL; if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP)) return -EINVAL; -- Jens Axboe