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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 7258ACA9EBC for ; Thu, 24 Oct 2019 03:32:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4897C21655 for ; Thu, 24 Oct 2019 03:32:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="l5kJGcsH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437228AbfJXDc4 (ORCPT ); Wed, 23 Oct 2019 23:32:56 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:35542 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392870AbfJXDcz (ORCPT ); Wed, 23 Oct 2019 23:32:55 -0400 Received: by mail-pg1-f195.google.com with SMTP id c8so8544526pgb.2 for ; Wed, 23 Oct 2019 20:32:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=x9yyQ2FOaYcmSfcpOJxtcwGG2Qu1XU68PHFcRqzXa3M=; b=l5kJGcsHDzkhBVaQTnz47UD9J1r2EmTtlolEqaO5EjuBlCtue3iG0RvKqmtBm2YwXR +8xepoTs24e/xk4M/s+f7E7+EwKKKZp/FE5YERFeXwtjz1auyqSYxDJUMg8UbLlaPFdB 3VffsRs0Ugwj+erGFiWCyDNCi9CJRFmgsh7fQHFjQ9wNJPwdh/k2PXzAOk0VFHWDHWu+ IajaTpK1/Gk7IONkVrWywQ/wiPOs4C5HohianltFhvm24sSeWfmeoRgxEk9olnOESANF O6TMAkmFj5lXneRX4r7OL4lDekc3wS/p1piBZzlQcYYcdTguBhAAsN5e4jrx1Bc5YZT1 OK6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=x9yyQ2FOaYcmSfcpOJxtcwGG2Qu1XU68PHFcRqzXa3M=; b=OdPP2J5ALBsneCRzmIsFkj5j0Nw4OLyIuwFY4ESjcLrgzNWtXX/DM8yfbMLzt3jYCm Lg17GsrmcZsKorYbqq6tvSJ6NuRROqWlzGVMODbn01biMweYkdJyL5ZaAXW4+JQ4MWUo AmiiOTQSGLvT6glTDTOzhx0bU7KLqA5DdbaHvzjpAVpgWJMI2o6KSiLmKb8SpfJlQlTc eWq72czsGJ9jB3PRMMQiUP9UiXd+gV6hzovSH9QxgLgN1TWsb1v4fd1PuujV7ymc2P// Q5dMQ4eUkqjSBDnINrfB+8zJ5Ft+r9dyssPXGtan+XYcfVlNRvh4CoQ8ZAF65Xhba9WS kAYA== X-Gm-Message-State: APjAAAUXrNP6a+XHNw9e+n1sYEy70jzrPEyfFMk5j9HnBwQt5y/9vRW1 2ppM6BZrVTYggqqUthQeaxFkKw== X-Google-Smtp-Source: APXvYqxbNeSTJySZFCyFfN/ef676Nbp3ELs2xUm7ue0KSYLuBZnSumm7Lik1hNs0oOuY7TDT2WmUdg== X-Received: by 2002:a63:c40e:: with SMTP id h14mr13966574pgd.254.1571887975017; Wed, 23 Oct 2019 20:32:55 -0700 (PDT) Received: from [192.168.1.188] ([66.219.217.79]) by smtp.gmail.com with ESMTPSA id n2sm25393079pgg.77.2019.10.23.20.32.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 Oct 2019 20:32:54 -0700 (PDT) Subject: Re: [PATCH] blk-mq: remove needless goto from blk_mq_get_driver_tag To: Bart Van Assche , =?UTF-8?Q?Andr=c3=a9_Almeida?= , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Cc: kernel@collabora.com, krisman@collabora.com References: <20191022174108.15554-1-andrealmeid@collabora.com> <2a8a99a6-4b39-e459-988a-ba9502919044@acm.org> From: Jens Axboe Message-ID: Date: Wed, 23 Oct 2019 21:32:52 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <2a8a99a6-4b39-e459-988a-ba9502919044@acm.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/23/19 7:34 PM, Bart Van Assche wrote: > On 2019-10-22 10:41, André Almeida wrote: >> The only usage of the label "done" is when (rq->tag != -1) at the >> begging of the function. Rather than jumping to label, we can just >> remove this label and execute the code at the "if". Besides that, >> the code that would be executed after the label "done" is the return of >> the logical expression (rq->tag != -1) but since we are already inside >> the if, we now that this is true. Remove the label and replace the goto >> with the proper result of the label. >> >> Signed-off-by: André Almeida >> --- >> Hello, >> >> I've used `blktest` to check if this change add any regression. I have >> used `./check block` and I got the same results with and without this >> patch (a bunch of "passed" and three "not run" because of the virtual >> scsi capabilities). Please let me know if there would be a better way to >> test changes at block stack. >> >> This commit was rebase at linux-block/for-5.5/block. >> >> Thanks, >> André >> --- >> block/blk-mq.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/block/blk-mq.c b/block/blk-mq.c >> index 8538dc415499..1e067b78ab97 100644 >> --- a/block/blk-mq.c >> +++ b/block/blk-mq.c >> @@ -1036,7 +1036,7 @@ bool blk_mq_get_driver_tag(struct request *rq) >> bool shared; >> >> if (rq->tag != -1) >> - goto done; >> + return true; >> >> if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag)) >> data.flags |= BLK_MQ_REQ_RESERVED; >> @@ -1051,7 +1051,6 @@ bool blk_mq_get_driver_tag(struct request *rq) >> data.hctx->tags->rqs[rq->tag] = rq; >> } >> >> -done: >> return rq->tag != -1; >> } > > Do we really need code changes like the above? I'm not aware of any text > in the Documentation/ directory that forbids the use of goto statements. Agree, it looks fine as-is. It's also a fast path, so I'd never get rid of that without looking at the generated code. -- Jens Axboe