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 B582914006; Sat, 13 Jul 2024 09:30:49 +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=1720863049; cv=none; b=n7PlhW1TzzjKhJcyzU8fnYEjuhUDqCZPubAtf+4mZY+EIjuZi9RY0sOT1APjj9vDkhJWMwbXOQ72L4ZIr7ZhzNGKZuLAXLTqmHdSSc//Q/9IDGxEpFZHtpSLv8/rshVKXxD+ML4x/f7famxKH0FzW6V94Xso9+m4tddPHnaathI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720863049; c=relaxed/simple; bh=egg7o9yZhEZ4EbCuIXAkxMp7kCxfrjNbsYkBpotkbek=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ePOV0UGK2YbPMCdHMS1fQXH1hVElbIhAFWlEnahry7UwaSnxBkWDn9crgghIwsKYKeNgLmBlUG5lZGN6i8gk8iEOrsbDnna2ISZIoDXJgISiwIQJM3hJFmQrr6635zpe+RsGxdNsgsEOoXdQQ63v3B9PLvvXLqxk+V6eId58EBw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WsBMuy+x; 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="WsBMuy+x" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4687C32781; Sat, 13 Jul 2024 09:30:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720863049; bh=egg7o9yZhEZ4EbCuIXAkxMp7kCxfrjNbsYkBpotkbek=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WsBMuy+x6YhhAPf/O+hmHpRhHG0Z5A99e16oKmuvbCV5oYqhaS/Box0aFULcsub9I b+wcae51nzJgy1ftGuFrkVLkRydctBIgb5mUO9H88MxeLCi0jmg1zQ23/9F9X723bR tDt/ZvgUdwi0L4ML2wVWunmL8+8M+WCyqcXVrZL4H3YtAYDPjMtFl0Ahg8lAQifMwF Kaitum+YwaEwKdcbs6j6+L39YcnJJDtTKO28yUgkfn7DMcrPXl4nzYS2cNcM88QsZY deg0uA4mNs6mWXamXcIrRmRnMgFPtCcERCtN4npChEBHpZSHM0GCiO0uTAIfDCCffJ 3mjlJztHsF/zQ== Date: Sat, 13 Jul 2024 12:30:43 +0300 From: Leon Romanovsky To: Easwar Hariharan Cc: Christoph Hellwig , Robin Murphy , Joerg Roedel , Will Deacon , Marek Szyprowski , Jason Gunthorpe , linux-kernel@vger.kernel.org, iommu@lists.linux.dev Subject: Re: [PATCH 2/2] dma: Add IOMMU static calls with clear default ops Message-ID: <20240713093043.GG1815706@unreal> References: <98d1821780028434ff55b5d2f1feea287409fbc4.1720693745.git.leon@kernel.org> <3912d498-5696-4e87-bab0-f35ef7ac6083@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3912d498-5696-4e87-bab0-f35ef7ac6083@linux.microsoft.com> On Fri, Jul 12, 2024 at 01:51:36PM -0700, Easwar Hariharan wrote: > On 7/11/2024 3:38 AM, Leon Romanovsky wrote: > > From: Leon Romanovsky > > > > Most of the IOMMU drivers are using the same DMA operations, which are > > default ones implemented in drivers/iomem/dma-iomem.c. So it makes sense > > to properly set them as a default with direct call without need to > > perform function pointer dereference. > > > > During system initialization, the IOMMU driver can set its own DMA and > > in such case, the default DMA operations will be overridden. > > > > Signed-off-by: Leon Romanovsky > > --- > > MAINTAINERS | 1 + > > drivers/iommu/dma-iommu.c | 24 +++++++------- > > include/linux/iommu-dma.h | 50 +++++++++++++++++++++++++++++ > > kernel/dma/iommu.h | 67 +++++++++++++++++++++++++++++++++++++++ > > kernel/dma/mapping.c | 9 +++--- > > 5 files changed, 134 insertions(+), 17 deletions(-) > > create mode 100644 include/linux/iommu-dma.h > > create mode 100644 kernel/dma/iommu.h > > > > > > diff --git a/include/linux/iommu-dma.h b/include/linux/iommu-dma.h > > new file mode 100644 > > index 000000000000..b42487bf8f8e > > --- /dev/null > > +++ b/include/linux/iommu-dma.h > > @@ -0,0 +1,50 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +/* > > + * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved > > + * > > + * DMA operations that map physical memory through IOMMU. > > + */ > > +#ifndef _LINUX_IOMMU_DMA_H > > +#define _LINUX_IOMMU_DMA_H > > + > > +#include > > + > > +#ifdef CONFIG_IOMMU_API > > +dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, > > + unsigned long offset, size_t size, > > + enum dma_data_direction dir, unsigned long attrs); > > +void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle, > > + size_t size, enum dma_data_direction dir, > > + unsigned long attrs); > > +int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, > > + enum dma_data_direction dir, unsigned long attrs); > > +void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, > > + enum dma_data_direction dir, unsigned long attrs); > > +#else > > +static inline dma_addr_t iommu_dma_map_page(struct device *dev, > > + struct page *page, > > + unsigned long offset, size_t size, > > + enum dma_data_direction dir, > > + unsigned long attrs) > > +{ > > + return DMA_MAPPING_ERROR; > > +} > > +static inline void iommu_dma_unmap_page(struct device *dev, > > + dma_addr_t dma_handle, size_t size, > > + enum dma_data_direction dir, > > + unsigned long attrs) > > +{ > > +} > > +static inline int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, > > + int nents, enum dma_data_direction dir, > > + unsigned long attrs) > > +{ > > + return -EINVAL; > > +} > > +static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, > > + int nents, enum dma_data_direction dir, > > + unsigned long attrs) > > +{ > > +} > > +#endif /* CONFIG_IOMMU_API */ > > +#endif /* _LINUX_IOMMU_DMA_H */ > > diff --git a/kernel/dma/iommu.h b/kernel/dma/iommu.h > > new file mode 100644 > > index 000000000000..4abaea2dfc49 > > --- /dev/null > > +++ b/kernel/dma/iommu.h > > @@ -0,0 +1,67 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +/* > > + * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved > > + * > > + * DMA operations that map physical memory through IOMMU. > > + */ > > +#ifndef _KERNEL_DMA_IOMMU_H > > +#define _KERNEL_DMA_IOMMU_H > > + > > +#include > > + > > +static inline dma_addr_t dma_iommu_map_page(struct device *dev, > > + struct page *page, size_t offset, > > + size_t size, > > + enum dma_data_direction dir, > > + unsigned long attrs) > > +{ > > + const struct dma_map_ops *ops = get_dma_ops(dev); > > + > > + if (ops->map_page) > > + return ops->map_page(dev, page, offset, size, dir, attrs); > > + > > + return iommu_dma_map_page(dev, page, offset, size, dir, attrs); > > +} > > + > > +static inline void dma_iommu_unmap_page(struct device *dev, dma_addr_t addr, > > + size_t size, > > + enum dma_data_direction dir, > > + unsigned long attrs) > > +{ > > + const struct dma_map_ops *ops = get_dma_ops(dev); > > + > > + if (ops->unmap_page) { > > + ops->unmap_page(dev, addr, size, dir, attrs); > > + return; > > + } > > + > > + iommu_dma_unmap_page(dev, addr, size, dir, attrs); > > +} > > + > > +static inline int dma_iommu_map_sg(struct device *dev, struct scatterlist *sg, > > + int nents, enum dma_data_direction dir, > > + unsigned long attrs) > > +{ > > + const struct dma_map_ops *ops = get_dma_ops(dev); > > + > > + if (ops->map_sg) > > + return ops->map_sg(dev, sg, nents, dir, attrs); > > + > > + return iommu_dma_map_sg(dev, sg, nents, dir, attrs); > > +} > > + > > +static inline void dma_iommu_unmap_sg(struct device *dev, > > + struct scatterlist *sg, int nents, > > + enum dma_data_direction dir, > > + unsigned long attrs) > > +{ > > + const struct dma_map_ops *ops = get_dma_ops(dev); > > + > > + if (ops->unmap_sg) { > > + ops->unmap_sg(dev, sg, nents, dir, attrs); > > + return; > > + } > > + > > + iommu_dma_unmap_sg(dev, sg, nents, dir, attrs); > > +} > > Can we use _dma_iommu_* instead of the transposition pattern we have > going on here? Having dma_iommu_* call iommu_dma_* is, I feel, a recipe > for confusion when reading the code, especially after a few passes when > the eyes start to glaze over. > > I think you're going for the typical pattern of iommu_dma* being an > internal detail that provides an implementation, but correct me if > there's some significance to the current naming scheme. Given the review feedback from Robin and Christoph, I will drop this layer anyway. Thanks > > Thanks, > Easwar