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 94510C433F5 for ; Thu, 7 Apr 2022 16:06:56 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=IrH9QKkBYO2sku5/sXyHjQuiGiQ0Kahamo2yN6MIlDc=; b=UPDt+8h8m8ndyuBo92Web1nERU FWUMDlULfsm5x+ze0+dB0ZJnVvZia+RTGVUlESCt8jxeFnZ62B96HkETvSWeTgru4QtbgasWA/fB4 fZbxHLZaNQLyxSQXzmsjTR1E2noDDda9mZnLdsc4bcZg/PNYJNXEBmQBSVeMXzq+Z9XKBvtyoQesX lnC1kE/wMQdJPtEHSnj3ugcq35Rtwz1Qa6YRnIDqczt4HZNL8d0rsSIfW1auQz8UO92uB7Ud/g/0K 3eIw6tVTRMPBNiCrnmN1qOI6TgJVVAPFPzxmLQPJhn+mIRSRAJAAqXPl6Byavo7GsvntZQd7kAhEa POJ/JclQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ncUeo-00CwLl-Tu; Thu, 07 Apr 2022 16:06:50 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ncUJ3-00CmfN-Cy for linux-nvme@lists.infradead.org; Thu, 07 Apr 2022 15:44:22 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id B026368AFE; Thu, 7 Apr 2022 17:44:17 +0200 (CEST) Date: Thu, 7 Apr 2022 17:44:17 +0200 From: Christoph Hellwig To: Hannes Reinecke Cc: Christoph Hellwig , Sagi Grimberg , Keith Busch , linux-nvme@lists.infradead.org Subject: Re: [PATCH 1/3] nvmet: make the subsystem type configurable Message-ID: <20220407154417.GC15988@lst.de> References: <20220407104808.29007-1-hare@suse.de> <20220407104808.29007-2-hare@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220407104808.29007-2-hare@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220407_084421_619179_501F4EAE X-CRM114-Status: GOOD ( 19.57 ) 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 Thu, Apr 07, 2022 at 12:48:06PM +0200, Hannes Reinecke wrote: > +static ssize_t nvmet_subsys_attr_type_store(struct config_item *item, > + const char *page, size_t count) > +{ > + struct nvmet_subsys *subsys = to_subsys(item); > + struct nvmet_port *p; > + struct nvmet_subsys_link *s; > + int i; > + > + if (subsys->subsys_discovered) > + return -EACCES; > + > + /* > + * Do not allow to change the subsystem type if it's > + * already linked to ports; the user should unlink it first. > + */ > + down_read(&nvmet_config_sem); > + list_for_each_entry(p, &nvmet_ports_list, global_entry) { > + list_for_each_entry(s, &p->subsystems, entry) { > + if (s->subsys == subsys) { > + up_read(&nvmet_config_sem); > + return -EACCES; > + } > + } > + } > + up_read(&nvmet_config_sem); Does this scale? Do we want a flag in the subsystem instead? > + for (i = 0; i < ARRAY_SIZE(nvmet_subsys_type_map); i++) { > + if (sysfs_streq(page, nvmet_subsys_type_map[i].name)) > + goto found; > + } > + > + pr_err("Invalid value '%s' for subsystem type\n", page); > + return -EINVAL; > + > +found: > + down_write(&nvmet_config_sem); > + if (nvmet_subsys_type_map[i].type == NVME_NQN_CURR) { > + if (!xa_empty(&subsys->namespaces)) { > + pr_err("discovery subsystem cannot have namespaces\n"); > + return -EINVAL; > + } > + } We can probably just check this unconditionally, as something that was a discovery subsystem before by definition can't have namespaces.