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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 03869C3A5A2 for ; Tue, 3 Sep 2019 16:37:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBDCE23711 for ; Tue, 3 Sep 2019 16:37:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731303AbfICQhS (ORCPT ); Tue, 3 Sep 2019 12:37:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45328 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730717AbfICQhO (ORCPT ); Tue, 3 Sep 2019 12:37:14 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 08C61308FC22; Tue, 3 Sep 2019 16:37:14 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-255.rdu2.redhat.com [10.10.120.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id EED7E608AB; Tue, 3 Sep 2019 16:37:10 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20190903085706.7700-1-hdanton@sina.com> References: <20190903085706.7700-1-hdanton@sina.com> <156717343223.2204.15875738850129174524.stgit@warthog.procyon.org.uk> To: Hillf Danton Cc: dhowells@redhat.com, viro@zeniv.linux.org.uk, Casey Schaufler , Stephen Smalley , Greg Kroah-Hartman , nicolas.dichtel@6wind.com, raven@themaw.net, Christian Brauner , keyrings@vger.kernel.org, linux-usb@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/11] General notification queue with user mmap()'able ring buffer [ver #7] MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <27532.1567528630.1@warthog.procyon.org.uk> Date: Tue, 03 Sep 2019 17:37:10 +0100 Message-ID: <27533.1567528630@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Tue, 03 Sep 2019 16:37:14 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hillf Danton wrote: > > + for (i = 0; i < wf->nr_filters; i++) { > > + wt = &wf->filters[i]; > > + if (n->type == wt->type && > > + (wt->subtype_filter[n->subtype >> 5] & > > + (1U << (n->subtype & 31))) && > > Replace the pure numbers with something easier to understand. How about the following: static bool filter_watch_notification(const struct watch_filter *wf, const struct watch_notification *n) { const struct watch_type_filter *wt; unsigned int st_bits = sizeof(wt->subtype_filter[0]) * 8; unsigned int st_index = n->subtype / st_bits; unsigned int st_bit = 1U << (n->subtype % st_bits); int i; if (!test_bit(n->type, wf->type_filter)) return false; for (i = 0; i < wf->nr_filters; i++) { wt = &wf->filters[i]; if (n->type == wt->type && (wt->subtype_filter[st_index] & st_bit) && (n->info & wt->info_mask) == wt->info_filter) return true; } return false; /* If there is a filter, the default is to reject. */ } David