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 74C35C55160 for ; Thu, 30 Jul 2026 12:41:06 +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=L4EDY/jtfMF8o5EnYm+BV4FTE+4q24E5jSx72xCBHTg=; b=1HQV0LhtPZMqxym48S7rF3hpwV cwoR7Q0zew8fw0u8J/hfJh2R7kjBfSYGUHvdNvHczddWhAkVJ8Xz87DnOlON8Wd0O9lPIj/6Z5vdU qUwWCGJu6kY8Y9ZhOh3dRtqrSAiASG3zoaRgK+fkG747yY3rqJ3pxGdIgLd+j7GlDW+ludtzeILOP T9L2fGdpmay8RP3vTIFFBCzRmdNymxtdvVhsEMGceUBKi1Hu2p1UomX9uJ4cf4ATYV462uDkApfxE 6gP4ZTzUAcSOb7K/OX/9zBCv4lzS+kkf7zQAtatbhxFY+NhEUmPfkM2txDpOhCBvf6z+Um5zZVyW6 Y1dmmWhA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wpQ4P-0000000AUYu-1DHR; Thu, 30 Jul 2026 12:41:05 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wpQ4N-0000000AUYm-30xe for linux-nvme@lists.infradead.org; Thu, 30 Jul 2026 12:41:03 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 77B7041563; Thu, 30 Jul 2026 12:41:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10B931F000E9; Thu, 30 Jul 2026 12:41:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785415263; bh=L4EDY/jtfMF8o5EnYm+BV4FTE+4q24E5jSx72xCBHTg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=SrmRK3ODWJVPdJ30iK6cJuoctIW29qNZbx8w80+o6oEVt/1CyWrWUh0GyJpHVsVi9 5KQTem+mGG1XT9RrLyEk7teMIFwy53mtM1p1wC2wJ0GX4gjyLuvsSvimA3Z0ZPNoEf qXRZ1ZB3utiXQy9AiDwX3cSNKuwzCDV1YuKvSPkhq/HLbiAgKFbUAVEcoaBtm/0p95 iwN93icpgxXRjhymibUFWVFiWdzAG7XP09TBLdn9qO6WzdFbTMGZmjSYyfYZCwCpVl EibhftPVHJ0wty7clUJD8mn3UL9+kaWIDBDachns0fjCS5M++aH7JOorJSdkl/QPb7 2ppQRWFiczP5g== Date: Thu, 30 Jul 2026 06:41:01 -0600 From: Keith Busch To: Christoph Hellwig Cc: Kanchan Joshi , Guixin Liu , Jens Axboe , Sagi Grimberg , Hannes Reinecke , Nilay Shroff , Chaitanya Kulkarni , linux-nvme@lists.infradead.org Subject: Re: [PATCH 4/4] nvme: clamp FDP placement handle count to the buffer size Message-ID: References: <20260730043105.3071328-1-kanie@linux.alibaba.com> <20260730043105.3071328-5-kanie@linux.alibaba.com> <749b4476-6d8c-4573-b51b-662b0ff57db3@samsung.com> <20260730113722.GD25454@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260730113722.GD25454@lst.de> 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, Jul 30, 2026 at 01:37:22PM +0200, Christoph Hellwig wrote: > On Thu, Jul 30, 2026 at 03:10:59PM +0530, Kanchan Joshi wrote: > > But I feel the need to improve (what we have) with a follow-up patch: > > 1. Revise the cap, from S8_MAX - 1 to U8_MAX; since bio->bi_write_hint > > is u8. > > Signed 8-bit -1 is indeed a really odd value, and from looking at the > original commit I'm not really sure how we arrived there. "S8_MAX - 1" is a weird way to represent it, but the reason that value was used (and it's admittedly not a good reason) was that the result fits in a page. Not that there's any restriction on admin commands using PRP lists; it's just a coincidental limit for all the driver initiated admin commands.