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 C518EEB64DD for ; Wed, 12 Jul 2023 16:23:19 +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: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=LopUFhhb9toXWOu0gdA3ljXayDvugPxlg9NY12mJyuk=; b=ivLOFk3xjq5seQ2fcwS0g7bWnS 9gyamCFs5sg5z2X/lyn5hVQvqTlR9msYL5lgAdacP9yAXkLahBjNzArfXzd5lUTRZMSUNCp+0wDpv EXuSa+IiO4+MCceRDE17la3ca/lJeB/MpvOOmwfQdHC8DZyimx/+68Hz7xkl21MnVCjX6u8wlREzj UiaP8JAzBIrAn20tUHfDZuJgkVBNqFgNXbqeqwoTpBVqAzk4SPZux8/0KzdzvtEwDQhunGR/k9vl8 XVxjdUMIuHdZwE6FDldfz8KSG/IZhWcKB5uVu5fDO8GkerxV6boJxnPoWxqpnVDjkgevkz4COSQZE sphSHDuA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qJccX-000ZNs-14; Wed, 12 Jul 2023 16:23:17 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qJccU-000ZN1-0H for linux-nvme@lists.infradead.org; Wed, 12 Jul 2023 16:23:15 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 52FEC67373; Wed, 12 Jul 2023 18:23:10 +0200 (CEST) Date: Wed, 12 Jul 2023 18:23:10 +0200 From: Christoph Hellwig To: Ming Lei Cc: Christoph Hellwig , Jens Axboe , Keith Busch , Sagi Grimberg , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org Subject: Re: [PATCH 1/4] block: don't unconditionally set max_discard_sectors in blk_queue_max_discard_sectors Message-ID: <20230712162310.GA29557@lst.de> References: <20230707094616.108430-1-hch@lst.de> <20230707094616.108430-2-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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-20230712_092314_267885_770A9E29 X-CRM114-Status: GOOD ( 14.19 ) 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 Mon, Jul 10, 2023 at 06:42:36PM +0800, Ming Lei wrote: > Userspace may write 0 to discard_max_bytes, and this patch still can > override user setting. True. Maybe the right thing is to have a user_limit field, and just looks at the min of that and the hw limit everywhere. These hardware vs user limits are a pain, and we'll probably need some proper infrastructure for them :P