From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC8AF1A76AD for ; Tue, 30 Jul 2024 17:33:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722360801; cv=none; b=EB+vJqJF9/MZ7GPaxBqut1eEK8tjqB2vsmVJwUA/xan/UfuIPp7QMRbgGgWHVmLkEy1Rxg2bdVHJOuhvkwMLFIDC/h0vp5cXaf/YkhUPi7pUxQfFbTSgdGoNdKE/wPSXUUSEnKsTWUqfhnV4Z8kioLv2rQ0ckEKonCSAIvisAe8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722360801; c=relaxed/simple; bh=4KMuEZm5R4J/RzKmjWI6KHgNwuAYrDoI9sUkj0rxfew=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GCsOt3Mz9Ulk98BoYm69Sqwbe2VzcVFqWQZ90rp1e/ENyJiaoSAbi7NgLW+UuRxGn7DBqxhic9IQlTELBCqJhjPh+FH9SM+Dg+ksrE7lqOVXpX8pcVPZlpt+uFesjnJz3aRdmjxbrIDNHS+hBEB36CkQamU86c9l3ltkc7Lo6rQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dny4sCfx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dny4sCfx" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240730172111.GA32320@lst.de> 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.