From patchwork Mon Jun 24 14:41:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Penyaev X-Patchwork-Id: 11013571 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 B1936112C for ; Mon, 24 Jun 2019 14:43:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A304E28BF2 for ; Mon, 24 Jun 2019 14:43:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 97ECB28C07; Mon, 24 Jun 2019 14:43:23 +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 320A028C03 for ; Mon, 24 Jun 2019 14:43:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728401AbfFXOmC (ORCPT ); Mon, 24 Jun 2019 10:42:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:50316 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726402AbfFXOmC (ORCPT ); Mon, 24 Jun 2019 10:42:02 -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 C9EE7AE32; Mon, 24 Jun 2019 14:42:00 +0000 (UTC) From: Roman Penyaev Cc: Roman Penyaev , Andrew Morton , Al Viro , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 02/14] epoll: introduce user structures for polling from userspace Date: Mon, 24 Jun 2019 16:41:39 +0200 Message-Id: <20190624144151.22688-3-rpenyaev@suse.de> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190624144151.22688-1-rpenyaev@suse.de> References: <20190624144151.22688-1-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 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 --- fs/eventpoll.c | 11 +++++++++++ include/uapi/linux/eventpoll.h | 29 +++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 622b6c9ef8c9..6d7a5fe4a831 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -4,6 +4,7 @@ * Copyright (C) 2001,...,2009 Davide Libenzi * * Davide Libenzi + * Polling from userspace support by Roman Penyaev */ #include @@ -104,6 +105,16 @@ #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. + * + * Before increasing the value see add_event_to_uring() and especially + * cnt_to_advance() functions and change them accordingly. + */ +#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..3317901b19c4 100644 --- a/include/uapi/linux/eventpoll.h +++ b/include/uapi/linux/eventpoll.h @@ -79,4 +79,33 @@ 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[] + __attribute__((__aligned__(EPOLL_USERPOLL_HEADER_SIZE))); +}; + #endif /* _UAPI_LINUX_EVENTPOLL_H */