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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8c37f51b732sm1696908185a.25.2026.01.13.07.08.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Jan 2026 07:08:29 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vfg0S-00000003udw-1o8a; Tue, 13 Jan 2026 11:08:28 -0400 Date: Tue, 13 Jan 2026 11:08:28 -0400 From: Jason Gunthorpe To: Mostafa Saleh Cc: "David Hildenbrand (Red Hat)" , 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, 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: <20260113150828.GP745888@ziepe.ca> References: <20260109195111.GQ545276@ziepe.ca> <20260112133256.GB745888@ziepe.ca> <20260112135208.GD745888@ziepe.ca> <746f5adb-1d91-4ca2-8ae0-a2d171203b66@kernel.org> <482f2f36-e906-492a-a80c-987bf7359d83@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: 95fnwkpokwa3awemynqg8k69oyx81tbo X-Rspamd-Queue-Id: BE0FA1C0017 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1768316910-567744 X-HE-Meta: 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 6mxf80IJ sWd9r9W2lVubJbFvzluiV1UGRaUoh0KBc136ufCEJybwJbPpK+C4atNXqT6ElnFEl5+YTBMIKKgwdd3apVxbkgWFuPzir+QbOusHSwRnnj3ONtxplghXYMfISq4i1iQpAM667zMFrBizCGfL9X7Je8X+vD+AwQGOXSPayW6ig8VboYnIQ8NaZV4E1YCZXJvbTdR47akI93qmVWY0tqOa0Zzwnmls5DHjP/djg8+egXJ17Qf5hsB/1gIlVSIvvxXWTgHuMPEYqgPKF8Gj604+G0qbA1MFV0eo7b1rS 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 Tue, Jan 13, 2026 at 10:49:28AM +0000, Mostafa Saleh wrote: > Would you have a problem if we added a new function in page_ext > "page_ext_from_phys()" as Jason suggested? Given the hidden complexity that David just pointed out I think this is essential to encapsulate it in a function. The function must be able to accept any phys_addr_t and safely returns NULL if page_ext cannot be used for some reason. Jason