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 01346C4332F for ; Thu, 22 Dec 2022 14:03:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235273AbiLVOC7 (ORCPT ); Thu, 22 Dec 2022 09:02:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230299AbiLVOC6 (ORCPT ); Thu, 22 Dec 2022 09:02:58 -0500 X-Greylist: delayed 65088 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 22 Dec 2022 06:02:56 PST Received: from msg-1.mailo.com (msg-1.mailo.com [213.182.54.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E5C86466; Thu, 22 Dec 2022 06:02:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mailo.com; s=mailo; t=1671717757; bh=rAiXl+mdpdCyxLsqZQpH6KekvLvHUkV0B51Cjb53HRA=; h=X-EA-Auth:Date:From:To:Cc:Subject:Message-ID:References: MIME-Version:Content-Type:In-Reply-To; b=i6BFp7rKXpgwTRO40SFxqhfrW02mMUMoJLjZTI+qZzI5AB/lStix1/QLLR5e80x3b rXfO3HCVxI1+sCYIX4j+Avg2DgqyxuBH9tegUoiJTNaEN/5KunUeMb1udV/C/D6wgE YgwnYM90DYx11Oobo7OSH2rmoiGHcjuvvi5F1s2s= Received: by b-6.in.mailobj.net [192.168.90.16] with ESMTP via ip-206.mailobj.net [213.182.55.206] Thu, 22 Dec 2022 15:02:37 +0100 (CET) X-EA-Auth: /Rb/X7L8cN/nRl02EkrqvOrn+ZbhNwuoCLwLDamRCNY6fwRTz1VkrjOc32l1B8MUotKGCIay5XAUGENZzl1xxEq2AY99KDTC Date: Thu, 22 Dec 2022 19:32:32 +0530 From: Deepak R Varma To: Greg Kroah-Hartman Cc: "Maciej W. Rozycki" , Jiri Slaby , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Saurabh Singh Sengar , Praveen Kumar , drv@mailo.com Subject: Re: [PATCH] tty: serial: convert atomic_* to refcount_* APIs Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Thu, Dec 22, 2022 at 06:55:01AM +0100, Greg Kroah-Hartman wrote: > On Thu, Dec 22, 2022 at 01:27:40AM +0530, Deepak R Varma wrote: > > The refcount_* APIs are designed to address known issues with the > > atomic_t APIs for reference counting. They protect the reference > > counters from overflow/underflow, use-after-free errors, provide > > improved memory ordering guarantee schemes, are 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, ...) > > > > > > Signed-off-by: Deepak R Varma > > --- > > Note: The patch is compile tested using dec_station.defconfig for > > MIPS architecture. > > Do you have this hardware? If not, please just do > one-variable-at-a-time so that if there are real problems, we can revert > the offending change easier. And it makes it simpler to review. Hi Greg, I do not have the hardware. I will make a one variable per patch change as suggest and send in a patch set. > > But, are you sure this is correct: > > > - 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) > > That is now different logic than before, why? Are you sure this is ok? This is not correct. I read it wrong. I will correct this in the patch set. > > I stopped reviewing here... Thanks. I will review the rest of the changes per your advise and make the corrections. regards, ./drv > > thanks, > > greg k-h