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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F7AFC3DA7D for ; Tue, 3 Jan 2023 09:01:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236955AbjACJA4 (ORCPT ); Tue, 3 Jan 2023 04:00:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233088AbjACJAx (ORCPT ); Tue, 3 Jan 2023 04:00:53 -0500 Received: from mail-ej1-f49.google.com (mail-ej1-f49.google.com [209.85.218.49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB7DD2668; Tue, 3 Jan 2023 01:00:51 -0800 (PST) Received: by mail-ej1-f49.google.com with SMTP id u19so72017143ejm.8; Tue, 03 Jan 2023 01:00:51 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OWuBtAVQiXhHtOCFE/dLo/ozknPRfRlKEoY8cqTUGrg=; b=O3WdqP7TlsVM27d6kRkSqaaay/Pg/Jb/WCcIR101fMKKiGYZoZvuH2nRHJoxFjUt9D cvnvsvIZRRSHOkEmrRzZ8G53Het6mv47meNh6DSzN6YfbGEFovEqNCLgZm6sURn1EO/Z ZiH8Mwjhwog67mPeRc9guKBHjAxwAaGDp6C1orIgQSmwcv3tuAACUCX0mcAYYtt80zrp 7ffIsH0GyOpmNeXikSAB4kcVLd6ZNFy1BKLCkSEItX/+uZcQ80S8zG8ynIez0Z0CO76D TMHJE7Et1+Sb6owcKrO0SQaXWlATOVvt6S3mRZ5wsLalwawrjyRkGb6ZRqW6U6ObPx/I 9rQQ== X-Gm-Message-State: AFqh2kqUGA5HcEzA9Iwo9RzQEhVUm97IoJ1Z71s+kbQZ3jryN6wQFyUl dHl8L2AVMDDRuzEC20zRad2n9yjpn4k= X-Google-Smtp-Source: AMrXdXvjjVtmb+IPI41f0KEHX6NQ/BQWLfXBVEzM+4TZL33Mu52QyaHDY+TvdpL+zFdhqW/MqztWIA== X-Received: by 2002:a17:906:9688:b0:7c1:1c7:3bad with SMTP id w8-20020a170906968800b007c101c73badmr35605095ejx.36.1672736450357; Tue, 03 Jan 2023 01:00:50 -0800 (PST) Received: from ?IPV6:2a0b:e7c0:0:107::aaaa:49? ([2a0b:e7c0:0:107::aaaa:49]) by smtp.gmail.com with ESMTPSA id nd12-20020a170907628c00b0084cc87c03ebsm2388616ejc.110.2023.01.03.01.00.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Jan 2023 01:00:49 -0800 (PST) Message-ID: <3c4e744f-c313-e195-af93-a22382c81bb6@kernel.org> Date: Tue, 3 Jan 2023 10:00:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH v4 2/2] tty: serial: dz: convert atomic_* to refcount_* APIs for irq_guard Content-Language: en-US To: Deepak R Varma , "Maciej W. Rozycki" , Greg Kroah-Hartman , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Saurabh Singh Sengar , Praveen Kumar References: <51ef854f77779c82010379420139993e12c38776.1671898144.git.drv@mailo.com> From: Jiri Slaby In-Reply-To: <51ef854f77779c82010379420139993e12c38776.1671898144.git.drv@mailo.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26. 12. 22, 7:21, Deepak R Varma wrote: > The refcount_* APIs are designed to address known issues with the > atomic_t APIs for reference counting. They provide following distinct > advantages: > - protect the reference counters from overflow/underflow > - avoid use-after-free errors > - provide improved memory ordering guarantee schemes > - neater and safer. > Hence, replace the atomic_* APIs by their equivalent refcount_t > API functions. > > This patch proposal address the following warnings generated by > the atomic_as_refcounter.cocci coccinelle script > atomic_add_return(-1, ...) ... > --- a/drivers/tty/serial/dz.c > +++ b/drivers/tty/serial/dz.c ... > @@ -400,18 +399,16 @@ static int dz_startup(struct uart_port *uport) > struct dz_port *dport = to_dport(uport); > struct dz_mux *mux = dport->mux; > unsigned long flags; > - int irq_guard; > int ret; > u16 tmp; > > - irq_guard = atomic_add_return(1, &mux->irq_guard); > - if (irq_guard != 1) > + refcount_inc(&mux->irq_guard); > + if (refcount_read(&mux->irq_guard) != 1) > return 0; > > - ret = request_irq(dport->port.irq, dz_interrupt, > - IRQF_SHARED, "dz", mux); > + ret = request_irq(dport->port.irq, dz_interrupt, IRQF_SHARED, "dz", mux); How is this related to the above described change? -- js suse labs