From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5A3E5C61DD3 for ; Tue, 1 Sep 2026 10:14:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XGLXmiWD3F2Rj4zO7/urRtXBPDds1U+hE4xfuZQdhqo=; b=cGpJPjOzXRHjZ6VTB4kaGAjjex +OY7yNeY1o9QT7/5yF1MpZK+A28xyUqvrJPErawUfkuHlZNmYYxCieNsDeY1ZdUEbHBI4atSs04jJ DLlEUwb7yxZWmD7gtmSS8aGhgUCU4LfdaTe6fSjM24ADnnfIcuX1lPpzoJK8zBQyJkXO7QV7/kbJz ItDkMSSVKSy/CH5h2O5wR2By52OGZsYsc/N/p0erwfHtn2hzw+ViIKqRDeDTfgrttLo0zLv9+4Gpv U7L6jCMspChOy+6bpzd44qHsaTi44+kbsHpvQcCEDN1pJrPXV1ShhC5NKpsyuWh04crgOky/989t/ 2vhW55Ww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1LVR-0000000BWF0-3t7r; Tue, 01 Sep 2026 10:14:17 +0000 Received: from out-60.mta0.migadu.com ([2001:41d0:1004:224b::3c] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1LVO-0000000BWE7-1e2t for linux-nvme@lists.infradead.org; Tue, 01 Sep 2026 10:14:16 +0000 X-Envelope-To: linux-nvme@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=EfL6eJsS70peRFTEVxSWSFw/s+Va4s7Cj1R4SG1OHlU=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1788257651; v=1; x=1788862451; b=mvu1ypx7YnZEg32SqiuwKC90hdZFvSDj/NYbbSSUWTlubRD3OpWfUocMUmdBAODAtEsWRiYj F8xqwh2exp6QoSx7X7yHV0yyQDFwoVGlk5DiJKi6Gs5bi49nsP/BdMFBUfw9YUwC6YEfMwvM8aN rIe7lRCOVfsMlcPjC7NVE9XE= X-Envelope-To: linux-nvme@lists.infradead.org Received: by mta10.migadu.com with ESMTPS id bdea76b3912144d3; Tue, 01 Sep 2026 10:14:11 +0000 X-Mizu-Trace-ID: bdea76b3912144d3 X-Migadu-Flow: FLOW_OUT Message-ID: <374a2e7b-6232-469c-ab75-e9ddfa884085@linux.dev> Date: Tue, 1 Sep 2026 11:14:10 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/2] nvme: add reference counting for transport modules To: Nilay Shroff , linux-nvme@lists.infradead.org Cc: kbusch@kernel.org, sagi@grimberg.me, hch@lst.de, axboe@fb.com, john.g.garry@oracle.com, wenxiong@linux.ibm.com, gjoyce@linux.ibm.com References: <20260831152006.819471-1-nilay@linux.ibm.com> Content-Language: en-US From: John Garry 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-20260901_031414_581661_91E3775C X-CRM114-Status: GOOD ( 14.94 ) 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 > >> When the ctrl ops module ref counting was originally introduced, the >> commit message mentioned a crash which it solves. >> >> So far for this problem we have seen a report that if we remove the >> module, the mounted FS will have IOs fail. The same can be experienced >> if the admin unbinds the device from the driver. However, I have not >> seen a mention of a crash, kernel data corruption, a hang, etc. >> > Yes I have also not observed a kernel crash or data corruption. > Regarding unbinding, this is triggered through the PCI/device-model > unbind path. The driver unbind callback returns void so the NVMe driver > has no way to reject or otherwise prevent the unbind operation from the > driver side. There's suppress_bind_attrs, but I don't think that anyone using VFIO would be happy if that were set. > The purpose of this patch is therefore to protect the > transport > module from being unloaded while the multipath head is still open.