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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id af79cd13be357-9158a237330sm2207058485a.16.2026.06.09.08.11.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Jun 2026 08:11:53 -0700 (PDT) Date: Tue, 9 Jun 2026 11:11:51 -0400 From: Gregory Price To: "David Hildenbrand (Arm)" Cc: linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-kernel@vger.kernel.org, kernel-team@meta.com, linux-cxl@vger.kernel.org, linux-kselftest@vger.kernel.org, djbw@kernel.org, vishal.l.verma@intel.com, dave.jiang@intel.com, akpm@linux-foundation.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, osalvador@suse.de, shuah@kernel.org, alison.schofield@intel.com, Smita.KoralahalliChannabasappa@amd.com, ira.weiny@intel.com, apopple@nvidia.com Subject: Re: [PATCH v4 3/9] mm/memory_hotplug: export mhp_get_default_online_type Message-ID: References: <20260605211911.2160954-1-gourry@gourry.net> <20260605211911.2160954-4-gourry@gourry.net> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Jun 09, 2026 at 11:52:21AM +0200, David Hildenbrand (Arm) wrote: > On 6/5/26 23:19, Gregory Price wrote: > > Drivers which may pass hotplug policy down to DAX need MMOP_ symbols > > and the mhp_get_default_online_type function for hotplug use cases. > > > > Some drivers (cxl) co-mingle their hotplug and devdax use-cases into > > the same driver code, and chose the dax_kmem path as the default driver > > path - making it difficult to require hotplug as a predicate to building > > the overall driver (it may break other non-hotplug use-cases). > > > > Export mhp_get_default_online_type function to allow these drivers to > > build when hotplug is disabled and still use the DAX use case. > > > > In the built-out case we simply return MMOP_OFFLINE as it's > > Ah, you mean without CONFIG_MEMORY_HOTPLUG > Yeah i'll update the commit message, thanks! > > non-destructive. The internal function can never return -1 either, > > so we choose this to allow for defining the function with 'enum mmop'. > > Acked-by: David Hildenbrand (Arm) > > -- > Cheers, > > David