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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1467FC3DA49 for ; Tue, 23 Jul 2024 14:06:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 644F66B00A1; Tue, 23 Jul 2024 10:06:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5F5926B00A2; Tue, 23 Jul 2024 10:06:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4BC316B00A3; Tue, 23 Jul 2024 10:06:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 2F6356B00A1 for ; Tue, 23 Jul 2024 10:06:45 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 979351A0158 for ; Tue, 23 Jul 2024 14:06:44 +0000 (UTC) X-FDA: 82371193128.23.918DD44 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by imf07.hostedemail.com (Postfix) with ESMTP id 6952E40164 for ; Tue, 23 Jul 2024 14:05:23 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=YQIxUIv0; spf=pass (imf07.hostedemail.com: domain of dakr@kernel.org designates 145.40.73.55 as permitted sender) smtp.mailfrom=dakr@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1721743502; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=AHW7l6a8PKMG5yI1JRi1e8XgbA+6hCT8NUyz4BRpowk=; b=ARPKzFbFpgxyfL93ttKAGOBY2t+v1dHbD2bbcB0NEftafv7UK8ZeiHj6t7KksmT8jqRJ3b rM6tN27jwXwZ2usre/DL5v+bWeshuj84XvwsawQj6MCQ0ArsGBW85sx3rITx9C0TfoGtxN ktjQZ1wXLiyzOLWIARpg5+chVSHzDa8= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=YQIxUIv0; spf=pass (imf07.hostedemail.com: domain of dakr@kernel.org designates 145.40.73.55 as permitted sender) smtp.mailfrom=dakr@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1721743502; a=rsa-sha256; cv=none; b=i+WtWNdmVLv/kV90G9pOLpxe5wVSybv5XmFbtENNfZVaCJ1VKoiiDUHHvMHk3XNc/VtCzn ZohVEOdEIaCJW/4o5NirzO8bxJydQZb/ScrLtzQqkE0tvYNvpzqdZgIPee8gTmQucPG9mq W6Ra8/NDwKFXCXZmYEE6isOstCzrI6Q= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id E96D4CE0E85; Tue, 23 Jul 2024 14:05:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D10ACC4AF11; Tue, 23 Jul 2024 14:05:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1721743519; bh=EGgf5pTY410KJ67p39mnjqLgRrmTHb+HFz152ObkjIo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YQIxUIv03F43BFfAm/TPO/aKoz5jkUBYzBBf6/5tCIH6syJMSf2mfcevW9EpLH+HA RGMjWDsSwDFVc9QJApdcP4Iren6uJ+OwBsBpPYncgWhr3VwRg7YHSwEOKisCe1bPJq gKIyZWf6jMdmhuImPeEJI83C4FMDzdJwdP9MpwJQntTlaZra5L2IEpkKvKgPh1qvSW 06d7W9RqXAp8bM3c6jyOZiFzhWhW7rPWY4gNT9GcecTsvsVO9JxvjjMt34aRTjxXJG 0k21hUObt3ziLpsxkAmT9xcqqmLv9aKjVEtb6G+Tiae/t/zt76S4MKvulhmJR5Wsca m/Uh3bXtAZgCw== Date: Tue, 23 Jul 2024 16:05:11 +0200 From: Danilo Krummrich To: Andrew Morton Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, vbabka@suse.cz, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, urezki@gmail.com, hch@infradead.org, kees@kernel.org, ojeda@kernel.org, wedsonaf@gmail.com, mhocko@kernel.org, mpe@ellerman.id.au, chandan.babu@oracle.com, christian.koenig@amd.com, maz@kernel.org, oliver.upton@linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org, rust-for-linux@vger.kernel.org Subject: Re: [PATCH v2 2/2] mm: kvmalloc: align kvrealloc() with krealloc() Message-ID: References: <20240722163111.4766-1-dakr@kernel.org> <20240722163111.4766-3-dakr@kernel.org> <20240722184348.3df3b433c8f49f123e1c8d9e@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240722184348.3df3b433c8f49f123e1c8d9e@linux-foundation.org> X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 6952E40164 X-Stat-Signature: 4cgt7kza65zkp59rouwezkos3gijcacz X-HE-Tag: 1721743523-146597 X-HE-Meta: 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 X68VPc7O Xp6P68mGGRdv07Bw2eAEJnNmHSaEmM8PbZbW1ORvbJVcZD1ux2RMlpr9ptTPyPTXVbbvyFtXVHkFYfjIx7sG3IHYhqYFMJiQCjzhOOH07LSnv3dVpDZ5G+9gPfX4gAv7qFDPBk25GpN9OmwTI5GuqXfDbqda2e+LJaORpRAucsN6eS1vStCesvP41Zb6kWy3Ag7ZfQqcLbjrRj7tgtD6YEKnllHLC71OnlL/lBPqxpAiKi+OVdpp1qIzMCL1B83+IluwqIZwW63wZasC9WMMrA5tczS7BrhUIyvJXm2058dp0zUyClBgIOxDbIlzc4iGswcPgCsuNqlfkwpgLTlhGSvTV4zpFXC7eCewrZIw+kokH0ERAf4FQa43I9kEczuAOTP7ZdL99EmcQyzk0DV1ta642Jw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jul 22, 2024 at 06:43:48PM -0700, Andrew Morton wrote: > On Mon, 22 Jul 2024 18:29:24 +0200 Danilo Krummrich wrote: > > > Besides the obvious (and desired) difference between krealloc() and > > kvrealloc(), there is some inconsistency in their function signatures > > and behavior: > > > > - krealloc() frees the memory when the requested size is zero, whereas > > kvrealloc() simply returns a pointer to the existing allocation. > > The old kvrealloc() behavior actually sounds somewhat useful. You've > checked that no existing sites were relying on this? Yes, I did. > > And that all existing kvrealloc() callers were (incorrectly) checking > for NULL? Seems that way. You mean for the initial allocation? Yes, but I also noticed that as long as the old kvrealloc() is called with p == NULL and oldsize == 0 it should work as well.