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 4F26035A151; Wed, 19 Nov 2025 13:45:32 +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=1763559934; cv=none; b=Dy4EdMDMK+WS6Dmvkm+Kp1J0Swaxt3NZ4NVfPvFv9Jsashw8I/T8+8H9O2fEcmY9QpZF1b73N6kcC6jWmz1SMdUyUBRmjhblf+LRYytDDjGzKM/uX6CNc0qpUwzc9RIDWos2dXUd2ANzn5KztXNZBb7mAoTvBJfpRD9Zy1LcIso= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763559934; c=relaxed/simple; bh=P3o8RHvDAEnUuERCe1BMnR1YwR+dMea/ZoAi5ZBXv90=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Lbf/AEABb3uAI1ThvZVvGpffm8GAltUHtFkwbJeYhI75EkNH+FkF00zu0jSOqtumrX+mZQMa0xMLHZML545DeDIZuZPsAyxPR5/q1rj1S/1lh465h2Trg8FpXZuhVw1I7iuzNtHHy71phLEi6s6njohhT4CcIpOoJLmW1cR7+O8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=t75TnyXa; 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="t75TnyXa" 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> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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> 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