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=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 EBBAAC4361B for ; Mon, 7 Dec 2020 15:35:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDEF222B40 for ; Mon, 7 Dec 2020 15:35:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727176AbgLGPfb (ORCPT ); Mon, 7 Dec 2020 10:35:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:45661 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726607AbgLGPfb (ORCPT ); Mon, 7 Dec 2020 10:35:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607355245; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TSar447mrODCorDJAwLnM2Hn87tX6f8JRTawBrR6gd8=; b=Wxs/1fkeB8va56pbAAdIQp22P5rdGqsViawMjhULfKNVg6Ajkcvjy/bF70TU5NRNzkcdXN 8FvIFgYrMpAgl7AY3g3f1qAyib3tFEsKY8W8uRvdhaBbh+GXUrhZ1cdthfuBEIdHx9oTmd ME6wCmw7+lA9kSBx0gnevlY4ZQETzRo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-377-gqdlbBjUO9OSLAgOEk22ow-1; Mon, 07 Dec 2020 10:34:01 -0500 X-MC-Unique: gqdlbBjUO9OSLAgOEk22ow-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9489D1005513; Mon, 7 Dec 2020 15:33:58 +0000 (UTC) Received: from llong.remote.csb (ovpn-118-86.rdu2.redhat.com [10.10.118.86]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7706A60CED; Mon, 7 Dec 2020 15:33:53 +0000 (UTC) Subject: Re: [PATCH 2/3] rwsem: Implement down_read_interruptible To: Peter Zijlstra Cc: "Eric W. Biederman" , linux-kernel@vger.kernel.org, Linus Torvalds , Ingo Molnar , Will Deacon , Jann Horn , Vasiliy Kulikov , Al Viro , Bernd Edlinger , Oleg Nesterov , Christopher Yeoh , Cyrill Gorcunov , Sargun Dhillon , Christian Brauner , Arnd Bergmann , Arnaldo Carvalho de Melo References: <87tut2bqik.fsf@x220.int.ebiederm.org> <87k0tybqfy.fsf@x220.int.ebiederm.org> <620f0908-c70a-9e54-e1b5-71d086b20756@redhat.com> <20201207090243.GE3040@hirez.programming.kicks-ass.net> From: Waiman Long Organization: Red Hat Message-ID: <7be81903-14e3-7485-83e7-02e65e80e8c3@redhat.com> Date: Mon, 7 Dec 2020 10:33:52 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201207090243.GE3040@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/7/20 4:02 AM, Peter Zijlstra wrote: > On Thu, Dec 03, 2020 at 08:59:13PM -0500, Waiman Long wrote: >> On 12/3/20 3:11 PM, Eric W. Biederman wrote: >>> +static inline int __down_read_interruptible(struct rw_semaphore *sem) >>> +{ >>> + if (!rwsem_read_trylock(sem)) { >>> + if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_INTERRUPTIBLE))) >>> + return -EINTR; >>> + DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); >>> + } else { >>> + rwsem_set_reader_owned(sem); >>> + } >>> + return 0; >>> +} >>> + >>> static inline int __down_read_killable(struct rw_semaphore *sem) >>> { >>> if (!rwsem_read_trylock(sem)) { >>> @@ -1495,6 +1507,20 @@ void __sched down_read(struct rw_semaphore *sem) >>> } >>> EXPORT_SYMBOL(down_read); >>> +int __sched down_read_interruptible(struct rw_semaphore *sem) >>> +{ >>> + might_sleep(); >>> + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); >>> + >>> + if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_interruptible)) { >>> + rwsem_release(&sem->dep_map, _RET_IP_); >>> + return -EINTR; >>> + } >>> + >>> + return 0; >>> +} >>> +EXPORT_SYMBOL(down_read_interruptible); >>> + >>> int __sched down_read_killable(struct rw_semaphore *sem) >>> { >>> might_sleep(); >> Acked-by: Waiman Long > Yeah, that seems correct.. There's an unfortunate amount of copy-paste > there though. > > Do we want to follow that up with something like this? I am actually thinking about similar streamlining once the patch lands. Your suggested changes look fine to me. Cheers, Longman