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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 04126D19501 for ; Mon, 26 Jan 2026 16:33:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 663DD6B0089; Mon, 26 Jan 2026 11:33:31 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 611536B008A; Mon, 26 Jan 2026 11:33:31 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 51E026B008C; Mon, 26 Jan 2026 11:33:31 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 433346B0089 for ; Mon, 26 Jan 2026 11:33:31 -0500 (EST) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E07A516084D for ; Mon, 26 Jan 2026 16:33:30 +0000 (UTC) X-FDA: 84374660580.14.66A4DA1 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf13.hostedemail.com (Postfix) with ESMTP id D854E2000C for ; Mon, 26 Jan 2026 16:33:28 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=glECKte0; spf=pass (imf13.hostedemail.com: domain of robh@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=robh@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1769445209; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=1110P4O7LSi8WXqTz4jJ2LZI4BaN9AEgj7xeGQ57r+U=; b=QPDpCLBcA7DMIZMUzjWZp0Glj4LqymrcBLtBcjKCTQNSAMVxYWdsqjql2LDLnIj2msOvbk skb53o0DNCS++c+2oDY2ImnzqIIJ1taabO+cpFUqZKm3k8+UwnxdOUTldE8/YdFcLvef8R BAPmza6JmCIET2RkbCxmuiigu8tZDpY= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=glECKte0; spf=pass (imf13.hostedemail.com: domain of robh@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=robh@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1769445209; a=rsa-sha256; cv=none; b=wPGkbR9RnOLoo9Tc+bsGXlEbC1SDGWudnaNw7atmU49YKnZgQ+8Kboqoyx008LrZkGjl+o bw6hnqUInMYxjB36SroSlIA3U8Oev30xjmy7McRoaaI8LTlnjkh3vtM2i5LZjsVNSWc6v8 uz4t0IMW/WzCh3uFTq6aX31JBuIO+l4= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id A73F544414 for ; Mon, 26 Jan 2026 16:33:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8BFF1C2BC87 for ; Mon, 26 Jan 2026 16:33:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769445207; bh=1110P4O7LSi8WXqTz4jJ2LZI4BaN9AEgj7xeGQ57r+U=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=glECKte0WuS1YaFZsotEBg9TsBrqPwW3Bmaqw+8bw+t94iKX8xFkDbiwMSPxOR039 E+LVjcee3NO/cjovpE9rIvAv89/EPdT6BuUAdDGFjpV6IbF5Rqe90jUwA0bSx93kZg 8Lm7QUmQlG5sdwKcN+W7s/YVREHZBDRXgcg2pcI94yqWk2ckiXayUn2fvE5V7FXxOk R1rSGT7j8AGPp9x3xIyCg6gFigG90GRLLcOR6UjTljc+Wn3gx/+uRkTa3AIZ75nTri gobdHZNZxddV5Px+L1FCv7Zia/QVpcCbft+oR/PAMTMmMANX1RDYURX68wXmPdETRF P4cdrj3qoQrLw== Received: by mail-ed1-f53.google.com with SMTP id 4fb4d7f45d1cf-6581327d6baso7159684a12.3 for ; Mon, 26 Jan 2026 08:33:27 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCUO14MQ0sBFCyGUPuldrTCGlY/8ZulvDaAgVDdM2Jpr6fqy0Gv+ZuGngMc6KaR/fLyvT3oVwFTijA==@kvack.org X-Gm-Message-State: AOJu0Yy7rg/8cWuVZCyX4DVc88tvMD4JA2cSrp3eUVXdV76YqCmSA/dq W/MOrCldjk7gqWEwtMhoJa7VUblZEuCoNi/bLD9BjyXBP9XjLld09w3Iz2YN1whDKKEwtvfbyR+ 8jjaIoRRi/s6aLNKwdPFmjYE+2PGLMA== X-Received: by 2002:a05:6402:51c7:b0:658:330c:f9af with SMTP id 4fb4d7f45d1cf-658706de926mr2985790a12.23.1769445205840; Mon, 26 Jan 2026 08:33:25 -0800 (PST) MIME-Version: 1.0 References: <20251210002027.1171519-1-oreoluwa.babatunde@oss.qualcomm.com> <99dc91c9-59fd-47c5-b1d9-157bda86ad59@samsung.com> <89f8895f-436d-4a73-a2c8-d61a2f4ee41a@samsung.com> In-Reply-To: <89f8895f-436d-4a73-a2c8-d61a2f4ee41a@samsung.com> From: Rob Herring Date: Mon, 26 Jan 2026 10:33:13 -0600 X-Gmail-Original-Message-ID: X-Gm-Features: AZwV_Qi4bswXzMTlSSlXlrhMA8xIhaBGN8wj5n0NOyn4w1lHAZaZH4If-414C3k Message-ID: Subject: Re: [PATCH] of: reserved_mem: Allow reserved_mem framework detect "cma=" kernel param To: Marek Szyprowski Cc: Oreoluwa Babatunde , ye.li@oss.nxp.com, kernel@oss.qualcomm.com, saravanak@google.com, akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, robin.murphy@arm.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux.dev, quic_c_gdjako@quicinc.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: D854E2000C X-Stat-Signature: yaoa7694skwk48enbnpg3xgrjjom5bk4 X-Rspam-User: X-HE-Tag: 1769445208-108042 X-HE-Meta: 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 vLJtY51w ssPs+G8pnWl53eR/TVc+gO5dbPhsPug2klgy/vhPBcNCqfVMg6eMLcZyegEoAXmQe9MTHo6/b8WmFpxvENktspN4/nwyR+8mtZ7BJlK9qfgUgMXAgOtKn/qkF9cbJtq4lAhMqy+9Wc6DXyLm2wl3RdEYGGMDZpY6SurxWOlQqsjlqKFYFTcvrROezpMAT1w0KJCd+CvOQg0GxZ5V3wO3IVz/+hQakSMeTCKcbfQS+LZFmcUkJyjhaFwAWyRNbGstjeA+soXNrXStHx2r+s9vLQxMkx7r1hZNR0aEQqUfaDUovJgEuh8AaUkCEtN2mC/LkPJYpberBqgP1YfdMKze8+rvJsHXMV7eXHNWpC/oEal6Ob2oHVjOkm5OA8Y2oecPHEczxLEigZ0KA7+6g3x/EeoP74A== 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, Jan 19, 2026 at 4:38=E2=80=AFAM Marek Szyprowski wrote: > > On 18.12.2025 15:42, Rob Herring wrote: > > On Thu, Dec 18, 2025 at 3:55=E2=80=AFAM Marek Szyprowski > > wrote: > >> On 10.12.2025 15:07, Rob Herring wrote: > >>> On Tue, Dec 9, 2025 at 6:20=E2=80=AFPM Oreoluwa Babatunde > >>> wrote: > >>>> When initializing the default cma region, the "cma=3D" kernel parame= ter > >>>> takes priority over a DT defined linux,cma-default region. Hence, gi= ve > >>>> the reserved_mem framework the ability to detect this so that the DT > >>>> defined cma region can skip initialization accordingly. > >>> Please explain here why this is a new problem. Presumably the > >>> RESERVEDMEM_OF_DECLARE hook after commit xxxx gets called before the > >>> early_param hook. And why is it now earlier? > >>> > >>> I don't really like the state/ordering having to be worried about in = 2 places. > >> I also don't like this spaghetti, but it originates from > >> commit 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved > >> memory regions are processed") and the first fixup for it: 2c223f7239f= 3 > >> ("of: reserved_mem: Restructure call site for > >> dma_contiguous_early_fixup()"). > > Honestly, this code wasn't great before. Every time it is touched it > > breaks someone. > > Indeed it got a bit complicated and needs some improvement, but first I > want to fix the the reported regression. This patch does this and it > looks that there are no ideas how to fix this in a different way. Rob, > could I apply it via dma-mapping-fixes? Sigh, yes. Acked-by: Rob Herring (Arm) Rob