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_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 79B7DC43387 for ; Wed, 9 Jan 2019 16:42:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 49C74206BB for ; Wed, 9 Jan 2019 16:42:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726887AbfAIQmD (ORCPT ); Wed, 9 Jan 2019 11:42:03 -0500 Received: from mx2.suse.de ([195.135.220.15]:57620 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726586AbfAIQkk (ORCPT ); Wed, 9 Jan 2019 11:40:40 -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 DE35CAF91; Wed, 9 Jan 2019 16:40:38 +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 06/15] epoll: introduce various of helpers for user structure lengths calculations Date: Wed, 9 Jan 2019 17:40:16 +0100 Message-Id: <20190109164025.24554-7-rpenyaev@suse.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190109164025.24554-1-rpenyaev@suse.de> References: <20190109164025.24554-1-rpenyaev@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Helpers for lengths-from-number and number-from-lengths calculations. Among them: ep_polled_by_user() - returns true if epoll was created with EPOLL_USERPOLL ep_user_ring_events_available() - returns true if there is something in user ring buffer 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 | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 9ec682b6488f..ae288f62aa4c 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -438,6 +438,65 @@ static void ep_nested_calls_init(struct nested_calls *ncalls) spin_lock_init(&ncalls->lock); } +static inline unsigned int to_items_length(unsigned int nr) +{ + struct eventpoll *ep; + + return (sizeof(*ep->user_header) + + (nr << ilog2(sizeof(ep->user_header->items[0])))); +} + +static inline unsigned int to_index_length(unsigned int nr) +{ + struct eventpoll *ep; + + return nr << ilog2(sizeof(*ep->user_index)); +} + +static inline unsigned int to_items_bm_length(unsigned int nr) +{ + return ALIGN(nr, 8) >> 3; +} + +static inline unsigned int to_items_nr(unsigned int len) +{ + struct eventpoll *ep; + + return (len - sizeof(*ep->user_header)) >> + ilog2(sizeof(ep->user_header->items[0])); +} + +static inline unsigned int to_items_bm_nr(unsigned int len) +{ + return len << 3; +} + +static inline unsigned int ep_max_items_nr(struct eventpoll *ep) +{ + return to_items_nr(ep->header_length); +} + +static inline unsigned int ep_max_index_nr(struct eventpoll *ep) +{ + return ep->index_length >> ilog2(sizeof(*ep->user_index)); +} + +static inline unsigned int ep_max_items_bm_nr(struct eventpoll *ep) +{ + return to_items_bm_nr(ep->items_bm_length); +} + +static inline bool ep_polled_by_user(struct eventpoll *ep) +{ + return !!ep->user_header; +} + +static inline bool ep_user_ring_events_available(struct eventpoll *ep) +{ + return ep_polled_by_user(ep) && + ep->user_header->head != ep->user_header->tail; +} + /** * ep_events_available - Checks if ready events might be available. * -- 2.19.1