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 22FB7CD484E for ; Tue, 12 May 2026 06:46:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 621F16B0088; Tue, 12 May 2026 02:46:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5F8C16B008A; Tue, 12 May 2026 02:46:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 536836B008C; Tue, 12 May 2026 02:46:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 42C966B0088 for ; Tue, 12 May 2026 02:46:45 -0400 (EDT) Received: from smtpin03.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id E5C1A120210 for ; Tue, 12 May 2026 06:46:44 +0000 (UTC) X-FDA: 84757834728.03.483823A Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf07.hostedemail.com (Postfix) with ESMTP id 5172940003 for ; Tue, 12 May 2026 06:46:43 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=iq4WyErZ; spf=pass (imf07.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@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=1778568403; 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=aZr0BaIdHSwJJbA1hkK0oJ81Kb/bYZuv87/XRa/7gMU=; b=ZOc5kS5jdAB/9+GBkQQlj0PN8G2OEB0Kigc9bAw3t7yekj9H/WnNVpNGq4x3EKoMPjbmb6 dNMOxa4b6/qOjl5Jz/IqyNPYaFsXzWKn2Y30/EHBwS8XdVBS6Y9Wftrcwgf9QcWkOKc4B0 r+UmRKKtt8vdMe3Wh1Hm9795CiDbLHQ= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778568403; a=rsa-sha256; cv=none; b=8b1P031SNtkFo22w28/iNH7UHBKUj2mFKI7/RDjKHFXO/D1eBNLb3l5UCo3GPIMo6gcluv fadJnQyg7NUrXmiGkm5iDEtPZ3hVyv0pdAUAzdy2LTW9NQZ8uXGF7GOTB3yVXGG8XckB1h J65JD9OhnekMIj/hg/xhng9xRPSj8A4= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=iq4WyErZ; spf=pass (imf07.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id A98B1600CB; Tue, 12 May 2026 06:46:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BD99C2BCB8; Tue, 12 May 2026 06:46:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778568402; bh=9lo3a8HNQUQfSXTkObC7PN3s4BMtQs5GlB1W7QFzB7g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iq4WyErZxLPa5eoiE6vV9GoH+CAJnCkGrApLT+EmefaDjXY/+2mDAOR7SPbNRKOSX DJAN1+v+XyLPXBDgwYfvsVN7qnZ3HoGKeFY7UKmQAav6t29Unz2ZDP8Djl25+dsovY Aax9awSrj1xfSIKYIH2onurNuLSiP+GeF98D63cA50VnbAYy7x7GTjkr7CSQTTuDwr pxwa6tzNkqebXStif+d+CflDW8A18wjD141aoQYoExJQ0uLgZHh7uW5U1UhJF/WT1t V9iESmawjhAQU/kVhViAuNkUm8I3bRmYilndNwTl4dh7aR+ECGgFJr/S8b+7EWpcxT oxkBD/BCsWz7Q== Date: Tue, 12 May 2026 09:46:34 +0300 From: Mike Rapoport To: Pratyush Yadav Cc: Pasha Tatashin , Alexander Graf , Muchun Song , Oscar Salvador , David Hildenbrand , Andrew Morton , Jason Miu , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 02/12] kho: store incoming radix tree in kho_in Message-ID: References: <20260429133928.850721-1-pratyush@kernel.org> <20260429133928.850721-3-pratyush@kernel.org> <2vxz4ikddi6y.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2vxz4ikddi6y.fsf@kernel.org> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 5172940003 X-Rspam-User: X-Stat-Signature: b87a18jid56afya87nop3zrbdxef5pri X-HE-Tag: 1778568403-640720 X-HE-Meta: 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 wk+OZbn2 39m/3Rx/dcDFiYRWeLVpxXZiPavkmy1Wgll8yPIVVlTR0BZD/OCAJz8DpxPv9r+29QLPcc1aM0cgae01O0qtjku4XH2HwzX7l4jQQOPb77weLet3YQ4qYfO0HWHrFV7FG3PZ91GZKxBrelNnvdWJ8m2tFW6HYARJxSjYlZhqlTccgdYW5kpv9UKGrsvn/WvDkc97ASO2zbQvxrtMp9Hhn1QxnYjYUTSL0OCRWUloNPvsS17xLjYm/JJsp1MMiJWxFCoTbsa4id+z3sYZd4ifTPg+slueVWwn+E+Z5asnTS9azZKNA+mfQIpryUJVhmtfj1ttS Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, May 11, 2026 at 06:28:21PM +0200, Pratyush Yadav wrote: > On Mon, May 11 2026, Mike Rapoport wrote: > > > On Wed, Apr 29, 2026 at 03:39:04PM +0200, Pratyush Yadav wrote: > >> From: "Pratyush Yadav (Google)" > >> > >> This allows other functions to also use the radix tree. While at it, > >> also use kho_get_mem_map_phys() instead of duplicating the code to get > >> the radix tree root from the FDT. > >> > >> Signed-off-by: Pratyush Yadav (Google) > >> --- > >> kernel/liveupdate/kexec_handover.c | 27 ++++++++------------------- > >> 1 file changed, 8 insertions(+), 19 deletions(-) > >> > >> diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c > >> index ba568d34c5b4..5758dc6fab5d 100644 > >> --- a/kernel/liveupdate/kexec_handover.c > >> +++ b/kernel/liveupdate/kexec_handover.c > >> @@ -1294,6 +1294,7 @@ struct kho_in { > >> char previous_release[__NEW_UTS_LEN + 1]; > >> u32 kexec_count; > >> struct kho_debugfs dbg; > >> + struct kho_radix_tree radix_tree; > >> }; > >> > >> static struct kho_in kho_in = { > >> @@ -1373,24 +1374,10 @@ EXPORT_SYMBOL_GPL(kho_retrieve_subtree); > >> > >> static int __init kho_mem_retrieve(const void *fdt) > >> { > >> - struct kho_radix_tree tree; > >> - const phys_addr_t *mem; > >> - int len; > >> - > >> - /* Retrieve the KHO radix tree from passed-in FDT. */ > >> - mem = fdt_getprop(fdt, 0, KHO_FDT_MEMORY_MAP_PROP_NAME, &len); > >> - > >> - if (!mem || len != sizeof(*mem)) { > >> - pr_err("failed to get preserved KHO memory tree\n"); > >> - return -ENOENT; > >> - } > >> - > >> - if (!*mem) > >> - return -EINVAL; > >> - > >> - tree.root = phys_to_virt(*mem); > >> - mutex_init(&tree.lock); > >> - return kho_radix_walk_tree(&tree, kho_preserved_memory_reserve); > >> + kho_in.radix_tree.root = phys_to_virt(kho_get_mem_map_phys(fdt)); > > > > Do we really want to remove an explicit check for 0 and get a WARN() in > > kho_radix_walk_tree()? > > If mem_map_phys is 0 then kho_populate() never sets kho_in.scratch_phys > and thus kho_mem_retrieve() never gets called. So here it will never be > 0, and if it is, a WARN() is certainly warranted. > > Perhaps I should add a comment since this isn't so obvious? Yes, please. After a few weeks it will be completely obscure. > > > >> + mutex_init(&kho_in.radix_tree.lock); > >> + return kho_radix_walk_tree(&kho_in.radix_tree, > >> + kho_preserved_memory_reserve); > >> } > >> > >> static __init int kho_out_fdt_setup(void) > >> @@ -1597,8 +1584,10 @@ void __init kho_memory_init(void) > >> if (kho_in.scratch_phys) { > >> kho_scratch = phys_to_virt(kho_in.scratch_phys); > >> > >> - if (kho_mem_retrieve(kho_get_fdt())) > >> + if (kho_mem_retrieve(kho_get_fdt())) { > >> kho_in.fdt_phys = 0; > >> + kho_in.radix_tree.root = NULL; > > > > I'd make kho_mem_retrieve() void and put these there. > > Sure, will do. > > > > >> + } > >> } else { > >> kho_reserve_scratch(); > >> } > >> -- > >> 2.54.0.545.g6539524ca2-goog > >> > > -- > Regards, > Pratyush Yadav -- Sincerely yours, Mike.