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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8f361ba3efdsm12323456d6.39.2026.06.30.23.23.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Jun 2026 23:23:57 -0700 (PDT) Date: Wed, 1 Jul 2026 02:23:52 -0400 From: Gregory Price To: Hannes Reinecke Cc: linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, driver-core@lists.linux.dev, linux-kselftest@vger.kernel.org, kernel-team@meta.com, david@kernel.org, osalvador@suse.de, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, djbw@kernel.org, vishal.l.verma@intel.com, dave.jiang@intel.com, alison.schofield@intel.com, akpm@linux-foundation.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, iweiny@kernel.org, Smita.KoralahalliChannabasappa@amd.com, apopple@nvidia.com Subject: Re: [PATCH v6 09/10] dax/kmem: add sysfs interface for atomic whole-device hotplug Message-ID: References: <20260630211842.2252800-1-gourry@gourry.net> <20260630211842.2252800-10-gourry@gourry.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Stat-Signature: sj1bhw54nx7p7c5bfhifgyqf5483ade4 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: B5A22C0007 X-HE-Tag: 1782887038-173736 X-HE-Meta: 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 xUOn/CVK 98wkz7DhFbxnSwUZEpSQpxcicr5AM9TzTzVi+cAihm1WCG7/NyCYqNOsQUZFLLPgm8lPXZ9NpGMZ0nx7FtrY7Gk/ZlCUSI+rVEOrAMuOWJn/OnoSPIyR1JLBm+DVdb5magPTOZRdDaLsw3jLPj8CoQZRJIVKFXNlXIBNc4qS+7EoeWtdxPR9Sz/PJFl1Je7WylHChjYH8uCygSou+17F8/0MAYiyum2XRU9PZfwOtrpkineMZY7dyJHsf8ZUln0BH5Q2V8km7c4RxnltELI8UyBF/3c118q0ak/W4znsF/rnKkIepE56pYFkXIqBC/HjBkwj0UPKNpK5CFD8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jul 01, 2026 at 08:13:28AM +0200, Hannes Reinecke wrote: > On 7/1/26 12:14 AM, Gregory Price wrote: > > On Tue, Jun 30, 2026 at 05:18:41PM -0400, Gregory Price wrote: > > > There is no atomic mechanism to offline and remove an entire > > > multi-block DAX kmem device. This is presently done in two steps: > > > > ... snip snip snip ... > > > > Sashiko pointed out a false-positive, but adding a fixup patch > > here that adds additional consistency. > > > > On total failure - release all resources. This makes the sysfs > > interface consistent with the probe failure path. > > > > Speaking of which ... > With this patch we now have _two_ interfaces to do the same thing. > And both will be generating uevents. > Which is far from ideal (one could easily envision _conflicting_ > udev rules, one set doing an 'online' on the old interface, > and another set doing an 'offline' on the new interface...) > Is there a way to not sending uevents for the old interface > or to make it configurable? We do not allow "offline" in the new interface. That fixes the entire issue - the blocks are gone, nothing to poke. ~Gregory