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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EDB88CF34B0 for ; Wed, 19 Nov 2025 13:45:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 56B296B0006; Wed, 19 Nov 2025 08:45:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 543CE6B002B; Wed, 19 Nov 2025 08:45:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 458F06B002C; Wed, 19 Nov 2025 08:45:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 33C896B0006 for ; Wed, 19 Nov 2025 08:45:35 -0500 (EST) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id AC18B59157 for ; Wed, 19 Nov 2025 13:45:34 +0000 (UTC) X-FDA: 84127478988.04.F2555A7 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf09.hostedemail.com (Postfix) with ESMTP id E8D71140006 for ; Wed, 19 Nov 2025 13:45:32 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=t75TnyXa; spf=pass (imf09.hostedemail.com: domain of leon@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=leon@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1763559933; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=k/NZI204oFTJcibyNFu8kuo/gp+s0LbmGQAfwS/N/QY=; b=Vjy7iEbPFZKqg9aU3SrqUCqvpKPfqJLSz1j+nzkXPqxs6hG+R1Lz0tTMST7PXaTIYjAOUG nCqZ2PDO5Nt+F+PQh53TMT58yOqaFgug6AeiwWZCO04PkSuLOUn8W7b5hBajEEnsPfpANG Rp1btAFi/e5a2dOQ4F5O94WAByZA9mk= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1763559933; a=rsa-sha256; cv=none; b=7cNYaH3hH9QSv9GskRJCo11+Tue7xgk0cGD7kBu+rzdOsd7KwoS3sF2xdfhSTur2MFnXnM zCgy1GMY1ju2cufAiF2g7q6VJDV0HA7GkvpbM7JwYzXyj6p1kCckU2QxiMUtjZgG2Flawv gRinL769GuoVIoDKLbxtKUGZh4Kgf1w= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=t75TnyXa; spf=pass (imf09.hostedemail.com: domain of leon@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=leon@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id EACF7439C7; Wed, 19 Nov 2025 13:45:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD7BBC16AAE; Wed, 19 Nov 2025 13:45:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763559931; bh=P3o8RHvDAEnUuERCe1BMnR1YwR+dMea/ZoAi5ZBXv90=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=t75TnyXaIaLVKA8TVdFOIbUfmeHo4/btOI2oLFyTwx1lCjsveSchI1EBPOOc8OfEU 7QixraT3KFGSPUvnTVnRthbFaGMDxNTZWUo5Tcxjf6aH53rpaqGFLVSFMNLDizUd3A QwSiZmvD//HgnssiilLrKxRM4vZ6cmc99aE4Coipe6CFlk1vQCZdASthF5vaDcQnkL MZ/cNswguYwRmgNRRMqMXz+l4ErdZVCb5X7Kve7bjXyjaAi9nArERygQ5n0D8BaTA5 3+fmL+QNcnPUcs4ADrhIjk+gdWlLU2nzJQQ5TGivxfxYWknTlcOCS90Tp/YEkddNL6 Jp9XI6WLvWISQ== Date: Wed, 19 Nov 2025 15:45:26 +0200 From: Leon Romanovsky To: Jason Gunthorpe Cc: "Tian, Kevin" , Bjorn Helgaas , Logan Gunthorpe , Jens Axboe , Robin Murphy , Joerg Roedel , Will Deacon , Marek Szyprowski , Andrew Morton , Jonathan Corbet , Sumit Semwal , Christian =?iso-8859-1?Q?K=F6nig?= , Kees Cook , "Gustavo A. R. Silva" , Ankit Agrawal , Yishai Hadas , Shameer Kolothum , Alex Williamson , Krishnakant Jaju , Matt Ochs , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , "iommu@lists.linux.dev" , "linux-mm@kvack.org" , "linux-doc@vger.kernel.org" , "linux-media@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linaro-mm-sig@lists.linaro.org" , "kvm@vger.kernel.org" , "linux-hardening@vger.kernel.org" , Alex Mastro , Nicolin Chen Subject: Re: [PATCH v8 06/11] dma-buf: provide phys_vec to scatter-gather mapping routine Message-ID: <20251119134526.GE18335@unreal> References: <20251111-dmabuf-vfio-v8-0-fd9aa5df478f@nvidia.com> <20251111-dmabuf-vfio-v8-6-fd9aa5df478f@nvidia.com> <20251119133000.GB18335@unreal> <20251119133708.GM17968@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20251119133708.GM17968@ziepe.ca> X-Stat-Signature: iojt8p3ynifk5514d85o83njw3z5mfsh X-Rspam-User: X-Rspamd-Queue-Id: E8D71140006 X-Rspamd-Server: rspam01 X-HE-Tag: 1763559932-591649 X-HE-Meta: U2FsdGVkX1/s9eC+jKylTWwj/Ys2wtkbqpVtW3y4P7YJ1qsxcH+n2VL3j8OQ4UY0fX2XBjEa3xN5CtpKW29cX6FdkIHLZYfW1ESSx4sPpPY1a4LPWph9LiDuXVmT9OSmWZU3aMsSDH8l7eF4wAYtD1zJ+T6eM/QhUOTAhshpQw6YX+wxunEFuQ3rQ6LiLss1GOkXi2zX49oMWR0PI5dQ5fsjnORETZpweevsl0kCGtj492dtFyjwHoivHEHqiorugGJjaYB84m29PLOSgwuLrP/09LRF1GUf2ITxaHoKje1wZNNrglF9krrTBEfk6nx0PdueYAOlkJ5B9RCSxFV5ZtziRIPAkqmpElQY7z26/FmBYx6ZX3Y2zaUDHbkohAwPojp42ykl8ApQNPXsvUSiLSqFsnUFmEhZ+xZqzwPSrIkNbeu0FIzU4EHMrB7JZSigTtVBCY79mhXRR5+JiVmq7gAzCnWC51EFsWMQBJSuW77+cfPEJXa7zj89ZfslehEyVFz2RN7rbYQL+6qh82R7+xiNnuoMssx3FEm74e4MogBVk7PHlsL6OVnwWxmukG75Tg7lFn/YzEDhOxGLKidNdq0W/5ldUwwCoTXVU/3jU2NynFvqO9a4e3CVR0gHEPY/ld/ztNeWq3QvBTr/nubzevQKLuSbQCHGqiyyCP45TBXmqlEdbKmARhg11X3n699vqD8ZChPPWwTBweabVzKB0zrhdnVAYYSQSLAjkeRwdMYTQ94koZZDHUlSpY+enajLrjhvMMC5d1oC3wIBsJKO4vpdGP3fkfL23DK321UybntNTzzQf4Ylau5J4xBdgBbu0bultuMgQ8/wZTNsGCmuk1S/401KB8aK0jTdI9//aSDWu1gvwyVBdTNc5eQtWoUrIX3VvZrlFZAtaJ+vDcLmUoWNGKIKC+7yoR2mOAC6m8TSx3wwDKf2WKMSq6Pnb+TWELRZRafKJGV2/8++U3B 5mgF3MqA x6knoZPSTPU6J+m/L+GUOyj8Ce2snZyeDxRVp1j5I6IKYudOZhyPe+AVExck+zNwFhqOvUC3g3wC3W2FYw7LvzacQBVkuPemlXsqoMZ3ZbdlftG5nEo3Xh6LPsMwpfNj9b1/E1rYZtwXE00wuYo44YzKCaCq+5eUvVRUcRJwpUp6zwcd7GPCyDq3f8hZgeN5GkimxptTHJGMw/BwksyB2YjmoTw0T7tKFfyfdqlIPVY4MROp9wD0l3tdeNaSu0Wt/+PPHt8nTLFuTViabuOAz298qbM4gMv9vSiqM90q+Jr04iqcO5y5VV9ks2tQiOJiaJ6rmmlca5KD5YzRRz5dILQrqHMLPbInXCVu++gc0T2z+dZMbkSbzi4sbvIjP8bKLugbqQ+xtalyOLF8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Nov 19, 2025 at 09:37:08AM -0400, Jason Gunthorpe wrote: > On Wed, Nov 19, 2025 at 03:30:00PM +0200, Leon Romanovsky wrote: > > On Wed, Nov 19, 2025 at 05:54:55AM +0000, Tian, Kevin wrote: > > > > From: Leon Romanovsky > > > > Sent: Tuesday, November 11, 2025 5:58 PM > > > > + > > > > + if (dma->state && dma_use_iova(dma->state)) { > > > > + WARN_ON_ONCE(mapped_len != size); > > > > > > then "goto err_unmap_dma". > > > > It never should happen, there is no need to provide error unwind to > > something that you won't get. > > It is expected that WARN_ON has recovery code, if it is possible and > not burdensome. It’s not necessary, but since I’m calculating mapped_len again, it’s natural—and completely harmless—to double-check the arithmetic. Thanks > > Jason