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 C641DCD4F26 for ; Fri, 26 Jun 2026 06:47:30 +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=tNYYrDuDMyYFDD0FDG/x48ay54+ujRwvxoRBAIfdcdA=; b=KC6M01BIZUyuj4cJ4IxEtuX56Y YOX00JFNKKVEn0XajXf30AUAgW3gv2syQ+bF9L2A25IgyOOv7wFIMLe+HInKr87kh/5vbV3Tv4CsA HLRpV46oraV93Tls0h1t53DBek/DHdh6sQ91bGobYdW48pbJG+0U56CxgODFVSXDju98zN8v7Z0Jo xJ5x8fQj6OQ967LREkbg192VxoHnJYRYmQj3vPWNa8wuivnWuGBWX6bMH5Km1rZfINgilA0XhHqWV qMONeWVnCj1pb5N2V/L+fpadL5X8qs+wBL0MJJlD61kINuFil7gR+KGqyhcdjl8i9X1PHiHzECvIP bHnHIXIg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wd0La-0000000AcYP-1qDG; Fri, 26 Jun 2026 06:47:30 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wd0LX-0000000AcXs-35Lt for linux-nvme@lists.infradead.org; Fri, 26 Jun 2026 06:47:28 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 5199B68B05; Fri, 26 Jun 2026 08:47:22 +0200 (CEST) Date: Fri, 26 Jun 2026 08:47:21 +0200 From: Christoph Hellwig To: Nilay Shroff Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, hch@lst.de, kbusch@kernel.org, sagi@grimberg.me, axboe@fb.com, bvanassche@acm.org, elver@google.com, gjoyce@linux.ibm.com Subject: Re: [PATCHv2 11/17] nvme: add Clang context annotations for nvme_queue::sq_lock Message-ID: <20260626064721.GA11106@lst.de> References: <20260614131541.2017845-1-nilay@linux.ibm.com> <20260614131541.2017845-12-nilay@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260614131541.2017845-12-nilay@linux.ibm.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260625_234727_924736_8751A326 X-CRM114-Status: GOOD ( 13.35 ) 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 Sun, Jun 14, 2026 at 06:45:26PM +0530, Nilay Shroff wrote: > Accesses to sq_tail used solely for tracing are annotated with > context_unsafe(), as they only require a lockless snapshot of the > value. Likewise, nvme_init_queue() and nvme_free_queue() operate on > queues that have not yet been published or are no longer reachable, > and therefore do not require sq_lock protection. Similarly, > nvme_alloc_sq_cmds() allocates memory for nvme_queue::sq_cmds for > the queue which is not yet published or in use and hence it's safe > to annotate all these helpers using context_unsafe. Accessing scalar fields without lock is pretty common. Don't we have an annotation that only requires the guarding lock for writes?