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b=HW0W0lCkK4CaHA4Z0Y6y0pe30gQQ2PlASyvv3YVMM07Fb1uDmQybHHE/TxTEwaxFd KejVucrd2Hg38/eDkNJxoiBSxWEgpH78R3wmtduIrTwWV8n5q9Rh1afo2ZJhCmXf3j W8Ixey6KgB6GqCdXjZY4eWayYOTd5PY8DkFdNsyK9Hc37dJz1FFEhimJm0klWU6OeT sr4iT5Vnhl6kMPgXxY1aDhCAncqtEb0rbRNheZ06p5ZXKyFEaqCVP9CEDQuAVdRSlJ asaZCz/xHBE/ktb7q2dHNRLThdHrW34nX/CPQzzXQgLgCQkjzsqjP+nI6QEuX5S9Dv 67jjjGxBIe0DA== Date: Mon, 19 Jan 2026 16:48:59 +0100 From: =?utf-8?B?SsO2cmcgUsO2ZGVs?= 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, 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 Subject: Re: [PATCH 1/2] mm/page_ext: Add page_ext_get_phys() Message-ID: References: <20260119142246.3821052-1-smostafa@google.com> <20260119142246.3821052-2-smostafa@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260119142246.3821052-2-smostafa@google.com> X-Rspamd-Queue-Id: 19320C0003 X-Stat-Signature: c8ieqn8rn6h14am5xkefupgomz5114hh X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1768837742-503605 X-HE-Meta: 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 Fv6R8WCf WVPhu6ur8/GZa1Nj2fCJXIZlD/A== 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 02:22:45PM +0000, Mostafa Saleh wrote: > +static inline struct page_ext *page_ext_get_phys(phys_addr_t phys) The name is misleading as it indicates that the function returns a physical address. Maybe name it page_ext_from_phys()? > +{ > + return NULL; > +} > + > static inline void page_ext_put(struct page_ext *page_ext) > { > } > diff --git a/mm/page_ext.c b/mm/page_ext.c > index 297e4cd8ce90..5fe65a0ac4f3 100644 > --- a/mm/page_ext.c > +++ b/mm/page_ext.c > @@ -538,6 +538,29 @@ struct page_ext *page_ext_get(const struct page *page) > return page_ext; > } > > +/** > + * page_ext_get_phys() - Get the page_ext structure for a physical address. > + * @phys: The physical address to query. > + * > + * This function safely gets the `struct page_ext` associated with a given > + * physical address. It performs validation to ensure the address corresponds > + * to a valid, online struct page before attempting to access it. > + * It should return NULL for (MMIO, ZONE_DEVICE, holes, offline memory) It should? -Joerg