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 0CEC1D26D94 for ; Fri, 9 Jan 2026 19:51:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 40DC16B0005; Fri, 9 Jan 2026 14:51:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3BB0A6B0089; Fri, 9 Jan 2026 14:51:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 29D5E6B008A; Fri, 9 Jan 2026 14:51:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 18D536B0005 for ; Fri, 9 Jan 2026 14:51:16 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 5C1B38C755 for ; Fri, 9 Jan 2026 19:51:15 +0000 (UTC) X-FDA: 84313469310.26.2DD432F Received: from mail-qk1-f169.google.com (mail-qk1-f169.google.com [209.85.222.169]) by imf19.hostedemail.com (Postfix) with ESMTP id 7DC101A000B for ; Fri, 9 Jan 2026 19:51:13 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=ziepe.ca header.s=google header.b=VdqRLgxh; spf=pass (imf19.hostedemail.com: domain of jgg@ziepe.ca designates 209.85.222.169 as permitted sender) smtp.mailfrom=jgg@ziepe.ca; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1767988273; a=rsa-sha256; cv=none; b=yfI8PvG72ccBTQ7q9PuYYV6CHAYfzW+xT66kyui6ZS/T4CMsIOli3V6PyT65akEYSkWGJF 85RdVOEsc9v0UU1Cd1KgpcQfdVofeAnT6etidzgeug5bC5P5yur4gkCCwd9VqFHh0SecRD HXSwJ7k3LjyEL9p4KsQpoF9GMjHhpCQ= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=ziepe.ca header.s=google header.b=VdqRLgxh; spf=pass (imf19.hostedemail.com: domain of jgg@ziepe.ca designates 209.85.222.169 as permitted sender) smtp.mailfrom=jgg@ziepe.ca; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767988273; 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=1HhQrwHPYHs7tKqcm2gO84BH3BiFPGmtv9DkIKXa95Q=; b=3f1d2pT4xN9FDDNLiLTE15bCaqHWZxxdJN3A5PkTWGI82HiYw/qYmAue5MLQSr3SEo2toU /sC+IGN4d8Mcs1ef0fykUynhc7AZTrU2mwUnEPN0e0vN9IsLk8NNz3y8u37GCWS6VMN4fk pNQxQsihzrgaKO2IThc7J9NkNSWfmPs= Received: by mail-qk1-f169.google.com with SMTP id af79cd13be357-8b25ed53fcbso621959085a.0 for ; Fri, 09 Jan 2026 11:51:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1767988272; x=1768593072; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=1HhQrwHPYHs7tKqcm2gO84BH3BiFPGmtv9DkIKXa95Q=; b=VdqRLgxhysA2fpopFpXqaZVrN8Xrq6FArBH5K75G5Zgk86Ke1E0CLgdtkDnQ5IazY9 II987h9jWFAwLufSUI5/pIDDEVcUvABYrp37UsaPSPPP5I0ajtDZ0ld93M4HEEw0Jdzx 2CqJGFPHZAdJbRJQZvALGCmoxP3pF1khFScpHo/6GeCfeBRbf3ozeSTNRw9OTMQeHLU8 TD6arNMFz1cPfhzzv0axEXYHWkjFvWYXYPRmBQRdGmN+DEELBpzBv456mGfV80zEzdca FmqsMWAKiyRsK9D0AxF2wYLJLFFUXI+AjAjo2N1IZBk4wX9qnah8je6wN56zz4AqqHyj NwQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767988272; x=1768593072; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=1HhQrwHPYHs7tKqcm2gO84BH3BiFPGmtv9DkIKXa95Q=; b=ZC3sSbJY5nqSjMAs+Yhhwf7z2ITggiAD39oIftjlkVMW6AFSYLAEOYpHCxa9oVCoVp mtp9JAeXLUZpUL4lcd/wLn5mdJTWvJ8zfCqIT4pT1tfat5f6xjo7JEYxava+amWvUWIm uKZQC4gY+Eq90Gd2oK1RnfM0Yn/92xNOQpxd4UjQcN9vqItITMgdWVapwt53GCSWlLEc SnywMKXy2lZoybzyA7tP23Bt+WBSxSKQ7QlBplMKFOF9CgvCg4nuREh35UyPGOl2EwWY yRD4UOQH+TCEwv79UH+jyJAc4uuRNnHcLiqVbGWGmk2s1vI5qXMvv/mIHwTu10e0snQv l4Aw== X-Gm-Message-State: AOJu0YyjECpWiYLr2ZTB97oGM5Gi5fQeY3IwseOvLDg/0j/wOUscgRWi dQge/H7CA9VsRbylS+wMFtPTzFnXBxMqoUsm1Rg1PFzWBH+QqP+cl6tSdz+95XyR6RU= X-Gm-Gg: AY/fxX70CPADQdwxxmdwh2NAtXDwQG4tSybIq2TuFkeKlCQlb8ODpSK0s1wrR24ci+u 88yZunMtnFwfAVw2Y1eeAD3zd6qLIh0P6K3t+p1nYjmUkzlsZv4Gw+Js71i6lr9IIi83HkAjizp fo6L7iPHpddarK0rxXgG+tpOyGrJBcEfEfoBFgHAFC/XurDmVuXW5EDD80z1zSEZOOgDtf/PmX5 yOIki7mrkZk1bpda+EMTnBdZkrdinpZ2OKTVozRbmC83QgMll/QQapDfgFKmCBwYGeI6/XAAXng /xYjRvZaYkbVy+K9RdFNX2p7cl9VIZQa/CMxQCgmRcoR3bikcnQhdbElSSYRhSk9eysSSCQtviJ 1QTdfD4+GBJO7SvwVaYFCLYIrdDVeu/LtlsYOjohTWsvzwO4BkTmzYQdsIanCHsqP+YuVSWqPIr 96YZH6IS3CGy46JgdgdpotinKpzvZEiYW3+rGE5Mah5wzg1uem9xz7IRwXVORBbgbGu90= X-Google-Smtp-Source: AGHT+IEZlrPxi+avVlluweNPtX7JEzZwtpBy5iyUb1htiohwK8TIi/Gv4SrQxJebEESGgl3Hi3a9jA== X-Received: by 2002:a05:620a:414a:b0:8c0:995b:e729 with SMTP id af79cd13be357-8c3893aa18cmr1552234485a.38.1767988272405; Fri, 09 Jan 2026 11:51:12 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-112-119.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.112.119]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8c37f400b59sm888623785a.0.2026.01.09.11.51.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Jan 2026 11:51:11 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1veIVr-0000000381J-1kSA; Fri, 09 Jan 2026 15:51:11 -0400 Date: Fri, 9 Jan 2026 15:51:11 -0400 From: Jason Gunthorpe To: Mostafa Saleh Cc: linux-mm@kvack.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, corbet@lwn.net, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, akpm@linux-foundation.org, vbabka@suse.cz, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, xiaqinxin@huawei.com, baolu.lu@linux.intel.com, rdunlap@infradead.org, Samiullah Khawaja Subject: Re: [PATCH v6 3/4] iommu: debug-pagealloc: Track IOMMU pages Message-ID: <20260109195111.GQ545276@ziepe.ca> References: <20260109171805.901995-1-smostafa@google.com> <20260109171805.901995-4-smostafa@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260109171805.901995-4-smostafa@google.com> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 7DC101A000B X-Stat-Signature: nr3wbwxxa88u1s1damzk94cnstbdy4de X-Rspam-User: X-HE-Tag: 1767988273-281072 X-HE-Meta: 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 OlYC/0lV VR2HZfbaKFTzSCG/pbERxhzBH18/gi55SM6SeeWO7+iICVv3Ci59OlgIZahXsNPBXgqfA/08YwCexMMF1RTMdFuwMmwC2w1dwgX3itTlMejmFo8K+1E3HjomJWl0c5gNidefYB2BQ7m+7DR3mIhjtZ66WAY/kFo/4H/7c1uCV4i3sOQZqNqLd5e3JD6SPnanQM3iQTYuM5qA29PaYv01I/pCGOSBYnghTGGMnPTWgKSCMXXX6mK2SkIYe6C9hqwqmQ0pqcz4iylqU4E9OjmdG1IkeFU762RwDcNwG 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 Fri, Jan 09, 2026 at 05:18:04PM +0000, Mostafa Saleh wrote: > +static struct page_ext *get_iommu_page_ext(phys_addr_t phys) > +{ > + struct page *page = phys_to_page(phys); > + struct page_ext *page_ext = page_ext_get(page); > + > + return page_ext; > +} > + > +static struct iommu_debug_metadata *get_iommu_data(struct page_ext *page_ext) > +{ > + return page_ext_data(page_ext, &page_iommu_debug_ops); > +} > + > +static void iommu_debug_inc_page(phys_addr_t phys) > +{ > + struct page_ext *page_ext = get_iommu_page_ext(phys); > + struct iommu_debug_metadata *d = get_iommu_data(page_ext); You cannot do this - phys_to_page() can only be called if we already know that phys is a struct page backed item and by the time you get here that information is lost. Probably the only way to resolve this is to somehow pass in an iommu prot flag that can tell the difference between struct page and non-struct page addresses. But I have to NAK this approach of blindly calling phys_to_page(). Jason