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 70B44C3DA49 for ; Tue, 30 Jul 2024 17:33:30 +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=uLk5AYcnqTui0+7pP8Xrn3qN9bM9SJWOSw8c/tbWTZQ=; b=d5DJaYbGHqhU8FXMcAdTJYxiu8 4jkPJuWZyFkOeNfafBW2ZUqyb1gOCpbnQ2NsNIMetJJ82dg5n/8ZBDrZMcWdYEjIyeD8JK+p09FK7 yh+MmDqRAJkoq27Eg8bEcZ/77x/jv1697Ehmal1TQ3tgROLx8cILDCEI1LQsg3sKtDP2K+8tIIcHD AskLM9DBOsVYCnCte6GaMzHuOEGbK303wzjfJOaIMWOrdjtEZ2u9/wSg+2awmwes12txkh1FArzz3 VH047BYIPF4NdsLxVI99jdQNNdit2M/mCkk6gOZ55xe+NTuWKz3EhdL7fSi85QIs2Px51pX5oqrvy slBezDiw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sYqj1-0000000G2Af-3Qb9; Tue, 30 Jul 2024 17:33:27 +0000 Received: from sin.source.kernel.org ([145.40.73.55]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sYqiy-0000000G2A1-00Mk for linux-nvme@lists.infradead.org; Tue, 30 Jul 2024 17:33:25 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 2411DCE10FC; Tue, 30 Jul 2024 17:33:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92D5BC4AF0A; Tue, 30 Jul 2024 17:33:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722360801; bh=4KMuEZm5R4J/RzKmjWI6KHgNwuAYrDoI9sUkj0rxfew=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dny4sCfxXZS+GgDPf7YE0V1Vhv4OT50CxYykBZt86KqVJjnB7cGUkybQkgsIQQoCn b1DQk4BeYoKdUTugLfF3AQLJ+TmMKWdtYiAaHItqGjH3cBY3zFzhKiM1qmzLuxjZcY z3tuHTlvVYXE1SBTWcfYjO48/gl/L3TOtzig1lkigx6xRdDFKwYrX3meqwCLe7mmeJ 8D+iK3W0xZDVv73FAtROahJSaQZsLVeOJP4NXtcPJyvwPW/6yYzu2/siFXLPAd4GKc iB9OBxOnkwyKI84GY7TvkJxMuvkMMzr3bsvaUWeGIf8sprhjA0I13ttD0zJ4ePqJmE e+jg4j2KvI+FA== Date: Tue, 30 Jul 2024 11:33:18 -0600 From: Keith Busch To: Christoph Hellwig Cc: Leon Romanovsky , Jens Axboe , Sagi Grimberg , Leon Romanovsky , Chaitanya Kulkarni , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] nvme-pci: add missing condition check for existence of mapped data Message-ID: References: <23e8ca814177474160a516e09b562af339cec837.1721816805.git.leon@kernel.org> <20240730172111.GA32320@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240730172111.GA32320@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240730_103324_240259_E528C94C X-CRM114-Status: GOOD ( 19.31 ) 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 Tue, Jul 30, 2024 at 07:21:11PM +0200, Christoph Hellwig wrote: > On Tue, Jul 30, 2024 at 11:09:04AM -0600, Keith Busch wrote: > > > + if (blk_rq_nr_phys_segments(req)) > > > + nvme_unmap_data(dev, req); > > > > This is already applied, but it is kind of strange. We get here only if > > metadata mapping fails. Is there actually a command that has metadata > > without data? > > Well, passthrough can always set metadata to map without data even > if there is no NVMe defined command that works that way, so we should > handle the error. That's what I initially thought too, but nvme passthrough maps metadata only if there's also user data. It doesn't look like you can even build a request to have metadata if it doesn't have user data: where does the bio come from in that case? And generic block stack maps it only for READ or WRITE commands, which must have payloads too, so I didn't find a path to reach this condition. Not a big deal, the patch is fine, but I was wondering if we need to change something else to allow the conditions it proposes to fix.