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 0A66AC61DD3 for ; Mon, 31 Aug 2026 13:04:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0AD2C6B0099; Mon, 31 Aug 2026 09:04:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 05E4F6B009D; Mon, 31 Aug 2026 09:04:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EDE096B00A1; Mon, 31 Aug 2026 09:04:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id D149D6B0099 for ; Mon, 31 Aug 2026 09:04:30 -0400 (EDT) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 61AF2A1F92 for ; Mon, 31 Aug 2026 13:04:30 +0000 (UTC) X-FDA: 85161583500.24.DD20B31 Received: from mail-pj2-f11.google.com (mail-pj2-f11.google.com [74.125.227.139]) by imf30.hostedemail.com (Postfix) with ESMTP id 801F48000E for ; Mon, 31 Aug 2026 13:04:28 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=ggqMHMEV; spf=pass (imf30.hostedemail.com: domain of chenwandun1@gmail.com designates 74.125.227.139 as permitted sender) smtp.mailfrom=chenwandun1@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788181468; b=4hY43k+zurky6T7MHhL1yioGNewRqFWm2p6C9RON3+jKi0QmeSTSOvFJGVaeGXSZGmUjo6 LR/ShnTaBHruTD4mvJogi+SulGfAGp5GaGZGil51kZ8SSYVbGe80XO+h64/TcDUs2HFxvR F1flRSTbmKkMjToDLN+oG3ZDSFtdv2E= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=ggqMHMEV; spf=pass (imf30.hostedemail.com: domain of chenwandun1@gmail.com designates 74.125.227.139 as permitted sender) smtp.mailfrom=chenwandun1@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788181468; 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=VXjjK4cQByHA+0LozWy93yMgZYx3/ZFKSUZa+XbHMGg=; b=C/sH8d9+JGiYB2MInRv22ik4TxSzicc/Oa6SA1R2wbBmLRSiqJURTJuoMCgR7RkEuCgS5z W2YD22vGPuaJ4IaYtBZOQZ5LQnbDNJD0Rw00HvBFmOtj3KGpx1xS1gMsICDPiPPJFKq13N 2Q+X54Mhie74Dch1+9F7xJUHDou1tc4= Received: by mail-pj2-f11.google.com with SMTP id 98e67ed59e1d1-396bf83d458so1279702a91.1 for ; Mon, 31 Aug 2026 06:04:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1788181467; x=1788786267; darn=kvack.org; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to :content-type; bh=VXjjK4cQByHA+0LozWy93yMgZYx3/ZFKSUZa+XbHMGg=; b=ggqMHMEVtcjJ0pWigRsCBM+OI0lzO52wC7IAg6TxdiNrTkuzlPRIEeiIqx+EussVru gesUBAklnoqHKVao6cgLa30lnyq8c13uqg9UKTwlBrk4E+SV4GI8ccA8xk1kr8cDVl/A 19FYAxIzUxCRKPzMFoljyJH9rVF1dPaFOipVGhw9i8vCfOOpi4/+ET6d3S8SNxvb2a10 +eeHpgmsjFiVGMlojEyZl8n5mK6yOPKhq8MpfpOgNn4qj4HMgy0ENUD65m5nhcSYD6E9 PR6fdNdeZ3lR5MKYdKCHw08hBBINy4Vo1ndr/rAaO+Gsu8xUoGqheymzNgOhpX9DjX5Y bTOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788181467; x=1788786267; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=VXjjK4cQByHA+0LozWy93yMgZYx3/ZFKSUZa+XbHMGg=; b=PeCR40wATgfHdwSEyDE4lIGSY0ToAmhljyQBTpYXBVoClbTK3ihyNLELQgPhdzbtQd b/gpg63uW/cU9UtNH80vSuNGe58J6nBcGDChb/IEffL3wFGTRllp2H73vwzFICRtJf++ xyYcaTbUJk61k68OnHtZGDZfcstlAJiM9bF3bYB6TuEmQ/ifeZwmnpWZ9IwMcFPQTxXa zY+7MYUJpWGnfOST1Aq15ij88vdZe7IUiof6Fo17SV4fou+z8n3Guo6xqTWkJTey/8C2 kLwrmfC3tjxfcDwRk04ERkYKfjXik+rnfJ90aPc9HsCsa3NjwZxA5LI/G/dVErqUcdrS 1+Wg== X-Forwarded-Encrypted: i=1; AKwUvBwRVt+ffycg1NMP/OTbkrFTYZAdHyg7JRQT2uxuG7e5msqpPJCuVufPri9tmctI6emzl2Cz2s/w3A==@kvack.org X-Gm-Message-State: AFuF++l8vJLiED725Q7KH5fTtl6l5yo4c6qM4Y112XzQNIOjobDzCspq N55q8dzao1aG8XWmfkQOyVTs7zl2MD7lKZsK71bvpR0qIBj0W8KcgWEN X-Gm-Gg: AYBFou2Ecb4EQloZC20P/A+OTSn+gW4czceaYViRb74Lwzh2Lmy2u8RkdV9ZNqr02B0 JGZx6zQihjgeN6K75hkwIY/I+Uc8axa1fkhkPDwZ9WMsgZpwA7uKjPZ0EbVqUlNvqALKCoNxPQj o11XN3S9M0fadW0upd07zzBXWcd1ThI9ZG3QmOmJHBgJKVO2udnaW7dhbiAfYJH3LeaSUhcTeRi ZMEzRrEIkh+yaYAvdYbbXrQZwlFnyguA0FOLHMiyvwt2ykc26kYnmGZRtjSPo+gDdEfG+1hDTwo r8XFC6BTT0/Odjh7ZhdxRT5f7eCeJqM1aFQN6TLZg5y4VtEffUd3ecFefrJ91KKn/v+UzCuqewN GmcjUBrqPr2fLwJdSd2ueZ20lKYqMvV/v+I04Ealy8jYcA3AU/uRniRv1vcsDuUSW2mbaCv8CzY DL/814xREP8vddYCNX/pQuhKGyfJchC3SqUGsVlPSeSBT3kl7EzPD+Lc/k5S4YmefOti7HRxoIE fRJrg== X-Received: by 2002:a17:90b:2888:b0:37f:e326:6557 with SMTP id 98e67ed59e1d1-39907ab0ea1mr1000718a91.4.1788181465569; Mon, 31 Aug 2026 06:04:25 -0700 (PDT) Received: from [10.125.112.20] ([122.11.210.25]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-396d6d29de3sm4981354a91.2.2026.08.31.06.04.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 31 Aug 2026 06:04:24 -0700 (PDT) Message-ID: Date: Mon, 31 Aug 2026 21:04:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/5] of: reserved_mem: skip init for regions whose early reservation failed To: Marek Szyprowski , robh@kernel.org, saravanak@kernel.org, rppt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: akpm@linux-foundation.org References: <20260818092420.2859026-1-chenwandun1@gmail.com> <20260818092420.2859026-2-chenwandun1@gmail.com> <72074a49-2963-4f96-b939-79bf95a829cb@samsung.com> Content-Language: en-US From: Wandun In-Reply-To: <72074a49-2963-4f96-b939-79bf95a829cb@samsung.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: ciy85trggx4nkqxpshrxepahs4oq9n54 X-Rspamd-Queue-Id: 801F48000E X-Rspamd-Server: rspam06 X-HE-Tag: 1788181468-529548 X-HE-Meta: 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 KJkVb7yz 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/26/26 21:14, Marek Szyprowski wrote: > On 18.08.2026 11:24, Wandun Chen wrote: >> From: Wandun Chen >> >> __reserved_mem_reserve_reg() discards the error from >> early_init_dt_reserve_memory() and returns 0 unconditionally, so the >> caller counts the node in total_reserved_mem_cnt and the late scan >> initializes it without checking whether the early reservation actually >> succeeded. A region whose reservation failed is then handed to a >> device assuming the memory is protected. >> >> Propagate the error so failed reservations are no longer counted, and >> record the failed nodes so fdt_scan_reserved_mem_late() can skip them. >> >> Recording the failed nodes explicitly is necessary because >> fdt_scan_reserved_mem_late() rescans the DT independently. It cannot >> tell from memblock whether early reservation succeeded. >> >> The failed-node array is bounded by MAX_RESERVED_REGIONS, the number >> of static regions is not bounded by it, so on overflow the extra nodes >> fall back to being initialized, which is the current behavior. > > I'm not very keen on such partial solution. Indeed we have no place to > > store the result of the early init call, but we can check if the given > > region has been earlier marked in memblock as reserved or no-map in > > fdt_scan_reserved_mem_late(). If those attributes don't match the > > region can be simply skipped then. Considering the later patches that reject reservations for overlapping nodes, checking the memblock state in fdt_scan_reserved_mem_late() may produce false positives. For example, if region A is reserved first and region B is a subset of A, reserving B will fail because it overlaps with A (in patch 02/03). However, during fdt_scan_reserved_mem_late(), B will still appear to be reserved because its range is already covered by A. As a result, B would be initialized even though its own reservation failed, which is contrary to the intended behavior. Best regards Wandun > > >> Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed") >> Signed-off-by: Wandun Chen >> --- >> drivers/of/of_reserved_mem.c | 65 ++++++++++++++++++++++++++++++------ >> 1 file changed, 54 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c >> index 8c9d6395d6a3..c6e73d710ee1 100644 >> --- a/drivers/of/of_reserved_mem.c >> +++ b/drivers/of/of_reserved_mem.c >> @@ -32,6 +32,30 @@ static struct reserved_mem *reserved_mem __refdata = reserved_mem_array; >> static int total_reserved_mem_cnt = MAX_RESERVED_REGIONS; >> static int reserved_mem_count; >> >> +static int reserve_failed_nodes[MAX_RESERVED_REGIONS] __initdata; >> +static int reserve_failed_nodes_cnt __initdata; >> + >> +static bool __init reserved_mem_node_reserve_failed(int node) >> +{ >> + int i; >> + >> + for (i = 0; i < reserve_failed_nodes_cnt; i++) >> + if (reserve_failed_nodes[i] == node) >> + return true; >> + return false; >> +} >> + >> +static bool __init record_reserve_failed_node(int node, const char *uname) >> +{ >> + if (reserve_failed_nodes_cnt == MAX_RESERVED_REGIONS) { >> + pr_err("too many failed regions, '%s' reservation failed\n", uname); >> + return false; >> + } >> + >> + reserve_failed_nodes[reserve_failed_nodes_cnt++] = node; >> + return true; >> +} >> + >> static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, >> phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap, >> phys_addr_t *res_base) >> @@ -141,7 +165,8 @@ static int __init early_init_dt_reserve_memory(phys_addr_t base, >> * first entry in 'reg' property >> */ >> static int __init __reserved_mem_reserve_reg(unsigned long node, >> - const char *uname) >> + const char *uname, >> + bool *should_record_failed_node) >> { >> phys_addr_t base, size; >> int len, err; >> @@ -149,6 +174,8 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, >> bool nomap; >> u64 b, s; >> >> + *should_record_failed_node = false; >> + >> prop = of_flat_dt_get_addr_size_prop(node, "reg", &len); >> if (!prop || !len) >> return -ENOENT; >> @@ -167,14 +194,20 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, >> base = b; >> size = s; >> >> - if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) { >> - fdt_fixup_reserved_mem_node(node, base, size); >> - pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n", >> - uname, &base, (unsigned long)(size / SZ_1M)); >> - } else { >> + if (!size) >> + return -EINVAL; >> + >> + err = early_init_dt_reserve_memory(base, size, nomap); >> + if (err) { >> + *should_record_failed_node = true; >> pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n", >> uname, &base, (unsigned long)(size / SZ_1M)); >> + return err; >> } >> + >> + fdt_fixup_reserved_mem_node(node, base, size); >> + pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n", >> + uname, &base, (unsigned long)(size / SZ_1M)); >> return 0; >> } >> >> @@ -306,10 +339,14 @@ void __init fdt_scan_reserved_mem_late(void) >> base = b; >> size = s; >> >> - if (size) { >> - uname = fdt_get_name(fdt, child, NULL); >> - fdt_init_reserved_mem_node(child, uname, base, size); >> - } >> + if (!size) >> + continue; >> + >> + if (reserved_mem_node_reserve_failed(child)) >> + continue; >> + >> + uname = fdt_get_name(fdt, child, NULL); >> + fdt_init_reserved_mem_node(child, uname, base, size); >> } >> >> /* check for overlapping reserved regions */ >> @@ -349,6 +386,7 @@ int __init fdt_scan_reserved_mem(void) >> >> fdt_for_each_subnode(child, fdt, node) { >> const char *uname; >> + bool should_record_failed_node; >> int err; >> >> if (!of_fdt_device_is_available(fdt, child)) >> @@ -356,9 +394,14 @@ int __init fdt_scan_reserved_mem(void) >> >> uname = fdt_get_name(fdt, child, NULL); >> >> - err = __reserved_mem_reserve_reg(child, uname); >> + err = __reserved_mem_reserve_reg(child, uname, >> + &should_record_failed_node); >> if (!err) >> count++; >> + else if (should_record_failed_node && >> + !record_reserve_failed_node(child, uname)) >> + /* Keep a slot for the untracked node's late initialization. */ >> + count++; >> >> /* >> * Save the nodes for the dynamically-placed regions > > Best regards