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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 47EF8C433E7 for ; Fri, 9 Oct 2020 20:04:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C1AD52225B for ; Fri, 9 Oct 2020 20:04:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="srX1rnlJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391317AbgJIUE3 (ORCPT ); Fri, 9 Oct 2020 16:04:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389246AbgJITwY (ORCPT ); Fri, 9 Oct 2020 15:52:24 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E954C0613D5 for ; Fri, 9 Oct 2020 12:52:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=3w99N6+9a+EbmOW5LL0tNVo1+ztrfFsJxS97E0AtHkg=; b=srX1rnlJywyeztvtZs/R0w0raM 7zJ9mpAiLcexFIr4M8ngodadItgDKC3j4s0U5FcC8ng02egWin6zWH8EsqWjgPvvqtT8iZLrNxnc4 OVWSEwR8ziHByszYrZ4Hi3aa5ri+BKsNUs6XvMhD4T5khiepp+g2IRGACb35LnH52QVsw8H0j5gSz 3zsnaK2DR/ne11/nQrzAwxvLDAACeH3rx9Xz5nHhro3NJrdn8Q6F4udn8JC0LEWD1Qjy3HN9QeNYF 1n8SF5x8dCYxWNM5BjJ+OCIkAugitOS9OFw/ib/5o86W8cZY0ennql0MeWYRaT5sW//wXcwkOqOAT FekOLjkA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQyQt-0001VM-5u; Fri, 09 Oct 2020 19:52:04 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 4C828307985; Fri, 9 Oct 2020 21:51:57 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 3A0FD20AEA645; Fri, 9 Oct 2020 21:51:57 +0200 (CEST) Date: Fri, 9 Oct 2020 21:51:56 +0200 From: Peter Zijlstra To: Shuah Khan Cc: johannes@sipsolutions.net, gregkh@linuxfoundation.org, rafael@kernel.org, keescook@chromium.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 04/11] drivers/base/devcoredump: convert devcd_count to counter_atomic32 Message-ID: <20201009195156.GC1073957@hirez.programming.kicks-ass.net> References: <9eee4448ec53e3a875e6785fa63bcda211e09d23.1602209970.git.skhan@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9eee4448ec53e3a875e6785fa63bcda211e09d23.1602209970.git.skhan@linuxfoundation.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 09, 2020 at 09:55:59AM -0600, Shuah Khan wrote: > counter_atomic* is introduced to be used when a variable is used as > a simple counter and doesn't guard object lifetimes. This clearly > differentiates atomic_t usages that guard object lifetimes. > > counter_atomic* variables wrap around to INT_MIN when it overflows > and should not be used to guard resource lifetimes, device usage and > open counts that control state changes, and pm states. > > devcd_count is used to track dev_coredumpm device count and used in > device name string. It doesn't guard object lifetimes, device usage > counts, device open counts, and pm states. There is very little chance > of this counter overflowing. Convert it to use counter_atomic32. > > This conversion doesn't change the overflow wrap around behavior. > > Reviewed-by: Greg Kroah-Hartman > Signed-off-by: Shuah Khan > --- > drivers/base/devcoredump.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/base/devcoredump.c b/drivers/base/devcoredump.c > index e42d0b514384..59bc48ee44af 100644 > --- a/drivers/base/devcoredump.c > +++ b/drivers/base/devcoredump.c > @@ -16,6 +16,7 @@ > #include > #include > #include > +#include > > static struct class devcd_class; > > @@ -255,7 +256,7 @@ void dev_coredumpm(struct device *dev, struct module *owner, > void *data, size_t datalen), > void (*free)(void *data)) > { > - static atomic_t devcd_count = ATOMIC_INIT(0); > + static struct counter_atomic32 devcd_count = COUNTER_ATOMIC_INIT(0); > struct devcd_entry *devcd; > struct device *existing; > > @@ -286,7 +287,7 @@ void dev_coredumpm(struct device *dev, struct module *owner, > device_initialize(&devcd->devcd_dev); > > dev_set_name(&devcd->devcd_dev, "devcd%d", > - atomic_inc_return(&devcd_count)); > + counter_atomic32_inc_return(&devcd_count)); > devcd->devcd_dev.class = &devcd_class; > > if (device_add(&devcd->devcd_dev)) This is like the absolute prime example of pointless wrappery. This is change for change's sake. This is absolute bullshit.