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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0956FC04AB4 for ; Thu, 16 May 2019 08:59:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D9F0D20818 for ; Thu, 16 May 2019 08:59:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727223AbfEPI73 (ORCPT ); Thu, 16 May 2019 04:59:29 -0400 Received: from mx2.suse.de ([195.135.220.15]:34916 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726448AbfEPI6Z (ORCPT ); Thu, 16 May 2019 04:58:25 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id ACB83AF50; Thu, 16 May 2019 08:58:24 +0000 (UTC) From: Roman Penyaev Cc: Azat Khuzhin , Roman Penyaev , Andrew Morton , Al Viro , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 02/13] epoll: introduce user structures for polling from userspace Date: Thu, 16 May 2019 10:57:59 +0200 Message-Id: <20190516085810.31077-3-rpenyaev@suse.de> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190516085810.31077-1-rpenyaev@suse.de> References: <20190516085810.31077-1-rpenyaev@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 This one introduces structures of user items array: struct epoll_uheader - describes inserted epoll items. struct epoll_uitem - single epoll item visible to userspace. Signed-off-by: Roman Penyaev Cc: Andrew Morton Cc: Al Viro Cc: Linus Torvalds Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org 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..161dfcbcf3b5 100644 --- a/include/uapi/linux/eventpoll.h +++ b/include/uapi/linux/eventpoll.h @@ -79,4 +79,32 @@ struct epoll_event { __u64 data; } EPOLL_PACKED; +#define EPOLL_USERPOLL_HEADER_MAGIC 0xeb01eb01 +#define EPOLL_USERPOLL_HEADER_SIZE 128 + +/* + * Item, shared with userspace. Unfortunately we can't embed epoll_event + * structure, because it is badly aligned on all 64-bit archs, except + * x86-64 (see EPOLL_PACKED). sizeof(epoll_uitem) == 16 + */ +struct epoll_uitem { + __poll_t ready_events; + __poll_t events; + __u64 data; +}; + +/* + * Header, shared with userspace. sizeof(epoll_uheader) == 128 + */ +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 */ -- 2.21.0