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[89.138.65.240]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-6a59e012f84sm635292a12.8.2026.08.22.17.46.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 22 Aug 2026 17:46:44 -0700 (PDT) Message-ID: Date: Sun, 23 Aug 2026 03:46:43 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V2] nvme: Add module reference counting for multipath devices From: Sagi Grimberg To: wenxiong@linux.ibm.com, linux-nvme@lists.infradead.org, kbusch@kernel.org Cc: gjoyce@linux.ibm.com, wenxiong@us.ibm.com References: <20260812223206.720363-1-wenxiong@linux.ibm.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260822_174646_673186_5683291C X-CRM114-Status: GOOD ( 11.73 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 23/08/2026 3:20, Sagi Grimberg wrote: > > > On 13/08/2026 1:32, wenxiong@linux.ibm.com wrote: >> From: Wen Xiong >> >> Add proper module reference counting to prevent premature unloading of >> NVMe transport modules while multipath namespaces are still active. >> >> When a namespace is added to a multipath device via >> nvme_mpath_add_disk(), >> the underlying transport module (PCIe, FC, RDMA, TCP, etc.) must remain >> loaded as long as the multipath device references that namespace. >> Without >> proper reference counting, the transport module could be unloaded while >> the multipath device is still using resources from that module, leading >> to the potential system crashes. >> >> This ensures the transport module remains loaded for the entire lifetime >> of the multipath namespace association. > > Can you provide details about the issue that this patch is supposed to > address? > (e.g. potential system crashes). The driver unload should be able to > disconnect all of the connected controllers when tearing down... OK, I now read the original report regarding nvme root device. please disregard.