From patchwork Mon Jan 21 20:14:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Penyaev X-Patchwork-Id: 10774509 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2734B1390 for ; Mon, 21 Jan 2019 20:16:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 15FCE2A411 for ; Mon, 21 Jan 2019 20:16:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0A10B2A874; Mon, 21 Jan 2019 20:16:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 988C62A411 for ; Mon, 21 Jan 2019 20:16:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728127AbfAUUPO (ORCPT ); Mon, 21 Jan 2019 15:15:14 -0500 Received: from mx2.suse.de ([195.135.220.15]:55534 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727867AbfAUUPO (ORCPT ); Mon, 21 Jan 2019 15:15:14 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id B45DAAFF5; Mon, 21 Jan 2019 20:15:12 +0000 (UTC) From: Roman Penyaev Cc: Roman Penyaev , Andrew Morton , Davidlohr Bueso , Jason Baron , Al Viro , "Paul E. McKenney" , Linus Torvalds , Andrea Parri , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH v2 02/13] epoll: introduce user structures for polling from userspace Date: Mon, 21 Jan 2019 21:14:45 +0100 Message-Id: <20190121201456.28338-3-rpenyaev@suse.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190121201456.28338-1-rpenyaev@suse.de> References: <20190121201456.28338-1-rpenyaev@suse.de> MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This one introduces structures of user items array: struct user_epheader - describes inserted epoll items. struct user_epitem - single epoll item, visible to userspace. Signed-off-by: Roman Penyaev Cc: Andrew Morton Cc: Davidlohr Bueso Cc: Jason Baron Cc: Al Viro Cc: "Paul E. McKenney" Cc: Linus Torvalds Cc: Andrea Parri Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- fs/eventpoll.c | 9 +++++++++ include/uapi/linux/eventpoll.h | 19 +++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 2cc183e86a29..f598442512f3 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -9,6 +9,8 @@ * * Davide Libenzi * + * Polling from userspace support by Roman Penyaev + * (C) Copyright 2019 SUSE, All Rights Reserved */ #include @@ -109,6 +111,13 @@ #define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry)) +/* + * That is around 1.3mb of allocated memory for one epfd. What is more + * important is ->index_length, which should be ^2, so do not increase + * max items number to avoid size doubling of user index. + */ +#define EP_USERPOLL_MAX_ITEMS_NR 65536 + struct epoll_filefd { struct file *file; int fd; diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h index 39dfc29f0f52..690a625ddeb2 100644 --- a/include/uapi/linux/eventpoll.h +++ b/include/uapi/linux/eventpoll.h @@ -79,4 +79,23 @@ struct epoll_event { __u64 data; } EPOLL_PACKED; +struct epoll_uitem { + __poll_t ready_events; + struct epoll_event event; +}; + +#define EPOLL_USERPOLL_HEADER_SIZE 128 +#define EPOLL_USERPOLL_HEADER_MAGIC 0xeb01eb01 + +struct epoll_uheader { + u32 magic; /* epoll user header magic */ + u32 header_length; /* length of the header + items */ + u32 index_length; /* length of the index ring, always pow2 */ + u32 max_items_nr; /* max number of items */ + u32 head; /* updated by userland */ + u32 tail; /* updated by kernel */ + + struct epoll_uitem items[] __aligned(EPOLL_USERPOLL_HEADER_SIZE); +}; + #endif /* _UAPI_LINUX_EVENTPOLL_H */