From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) (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 8AC47515889 for ; Tue, 13 Oct 2026 15:14:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.118.77.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791904494; cv=none; b=jtmNpS5j+SqK81cn9nmHmBhI8+zDzbckKIImMEDp/yCZNU6/ibO1KBEPC/ms04oXw2JNHr3DWFrRT+LnEfewgZmeQ9EMOewH9qcNGu3qaOaI6UN4utnZ0+mWS63DyDi3eCCueubC5m6qx4qdDDiuUftz9M6hBUhv56BJonOJxLM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791904494; c=relaxed/simple; bh=i+Kgazn/A26d/jnqiULLIMIDKPiJkQnG+4y4AEyQ0QM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:From:In-Reply-To: Content-Type:References; b=Ex9yD8zpBFVOEgtBEShqLlm7s8TZ/uqSMt49l38stUkuksqsrW3ypDgqHnPvii7VL5iFcUiEyu6bOFrsOUlvnXtjX2QyjDMR270aQZF7quR+wdjOpIxRc0jO3IcOctLmaTmaM+Pp3cMP2g+Hz8/QIM37sxIBh0xw0EShYJpbT+4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=J+XhwAOA; arc=none smtp.client-ip=210.118.77.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="J+XhwAOA" Received: from eucas1p1.samsung.com (unknown [182.198.249.206]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20261013151449euoutp01c1df306d103844a952749ded6649a722~eH6Ou0TR01757917579euoutp01D for ; Tue, 13 Oct 2026 15:14:49 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20261013151449euoutp01c1df306d103844a952749ded6649a722~eH6Ou0TR01757917579euoutp01D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1791904489; bh=TucBtbT8WUZnaL4AAJ/KHE6ifLcnYplyyYn4+mym8U0=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=J+XhwAOA1Ibu2V+msB3Z0/x6R4HuqR9MG22HyLGM7owRGWCRXUhVdxR5ueM45Dkxe +h5MPmkK3ly/kBNnW0tobrHknGR3YSCnvms3hmIrsV0lAKjHyIWxY2i0a1hKd+fUbw x3DbyRVnt0NbAqmkuY5NdDJTr9fRu6XScs7BXLJg= Received: from eusmtip2.samsung.com (unknown [203.254.199.222]) by eucas1p2.samsung.com (KnoxPortal) with ESMTPA id 20261013151449eucas1p25f9863bc10f769dc04db0e1cc7d22a8b~eH6OfGkV41073110731eucas1p2Y; Tue, 13 Oct 2026 15:14:49 +0000 (GMT) Received: from [106.210.134.192] (unknown [106.210.134.192]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20261013151448eusmtip2e76adc8617f398a4f3b94dab5e502846~eH6N6x-bM1039010390eusmtip2y; Tue, 13 Oct 2026 15:14:48 +0000 (GMT) Message-ID: <2f3f6025-1bea-4957-ae2f-219666c426aa@samsung.com> Date: Tue, 13 Oct 2026 17:14:48 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Betterbird (Windows) Subject: Re: [PATCH] dma-debug: Skip cacheline tracking for MMIO mappings To: Robin Murphy , Leon Romanovsky , =?UTF-8?Q?Niklas_S=C3=B6derlund?= , Arnd Bergmann , Vinod Koul Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org Content-Language: en-US From: Marek Szyprowski In-Reply-To: Content-Transfer-Encoding: 7bit X-CMS-MailID: 20261013151449eucas1p25f9863bc10f769dc04db0e1cc7d22a8b X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20261013124404eucas1p18634616550d426fa68a0e919b73be3bb X-EPHeader: CA X-CMS-RootMailID: 20261013124404eucas1p18634616550d426fa68a0e919b73be3bb References: <20261013-dma-debug-fixes-v1-1-1ad1f471cc61@nvidia.com> On 13.10.2026 14:43, Robin Murphy wrote: > On 13/10/2026 12:44 pm, Leon Romanovsky wrote: >> From: Leon Romanovsky >> >> Mapping one MMIO dma-buf for many RDMA importers overflows dma-debug's >> cacheline overlap counter and triggers a warning. DMA_ATTR_MMIO mappings >> must never be CPU-cacheable, so CPU cacheline overlap tracking does not >> apply to them. >> >> Skip MMIO entries in both cacheline insertion and removal. Keep them in >> the DMA entry hash so mapping and unmapping checks still run. > > Seems fair; > > Reviewed-by: Robin Murphy > > [...] >> >> Fixes: 0e74b34dfc33 ("dma-debug: add support for resource mappings") > > Although it would be a challenge to backport _that_ far, so more realistically I'd probably say: > > Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping routine") > > since regular dma_map_resource() users are still never going to hit this making their one-off mapping of a UART FIFO or whatever. Applied to dma-mapping-for-next with updated Fixes: tag, thanks! Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland