kernel/include/linux/dma-contiguous.h, branch 0x221E-v0.0-v7.0

dma-mapping: merge into

2020-10-06T05:07:04Z

Merge dma-contiguous.h into dma-map-ops.h, after removing the comment describing the contiguous allocator into kernel/dma/contigous.c. Signed-off-by: Christoph Hellwig

dma-contiguous: remove dma_contiguous_set_default

2020-10-06T05:07:03Z

dma_contiguous_set_default contains a trivial assignment, and has a single caller that is compiled if CONFIG_CMA_DMA is enabled. Signed-off-by: Christoph Hellwig

dma-contiguous: remove dev_set_cma_area

2020-10-06T05:07:03Z

dev_set_cma_area contains a trivial assignment. It has just three callers that all have a non-NULL device and depend on CONFIG_DMA_CMA, so remove the wrapper. Signed-off-by: Christoph Hellwig

dma-contiguous: remove dma_declare_contiguous

2020-10-06T05:07:03Z

dma_declare_contiguous is a trivial wrapper around dma_contiguous_reserve_area and just has a single caller. Signed-off-by: Christoph Hellwig

dma-contiguous: provide the ability to reserve per-numa CMA

2020-09-01T07:19:28Z

Right now, drivers like ARM SMMU are using dma_alloc_coherent() to get coherent DMA buffers to save their command queues and page tables. As there is only one default CMA in the whole system, SMMUs on nodes other than node0 will get remote memory. This leads to significant latency. This patch provides per-numa CMA so that drivers like SMMU can get local memory. Tests show localizing CMA can decrease dma_unmap latency much. For instance, before this patch, SMMU on node2 has to wait for more than 560ns for the completion of CMD_SYNC in an empty command queue; with this patch, it needs 240ns only. A positive side effect of this patch would be improving performance even further for those users who are worried about performance more than DMA security and use iommu.passthrough=1 to skip IOMMU. With local CMA, all drivers can get local coherent DMA buffers. Also, this patch changes the default CONFIG_CMA_AREAS to 19 in NUMA. As 1+CONFIG_CMA_AREAS should be quite enough for most servers on the market even they enable both hugetlb_cma and pernuma_cma. 2 numa nodes: 2(hugetlb) + 2(pernuma) + 1(default global cma) = 5 4 numa nodes: 4(hugetlb) + 4(pernuma) + 1(default global cma) = 9 8 numa nodes: 8(hugetlb) + 8(pernuma) + 1(default global cma) = 17 Signed-off-by: Barry Song Signed-off-by: Christoph Hellwig

dma-direct: fix zone selection after an unaddressable CMA allocation

2019-08-20T22:14:10Z

The new dma_alloc_contiguous hides if we allocate CMA or regular pages, and thus fails to retry a ZONE_NORMAL allocation if the CMA allocation succeeds but isn't addressable. That means we either fail outright or dip into a small zone that might not succeed either. Thanks to Hillf Danton for debugging this issue. Fixes: b1d2dc009dec ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers") Reported-by: Tobias Klausmann Signed-off-by: Christoph Hellwig Tested-by: Tobias Klausmann

dma-contiguous: fix !CONFIG_DMA_CMA version of dma_{alloc, free}_contiguous()

2019-06-03T14:00:07Z

Commit fdaeec198ada ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers") adds a pair of new helper functions so as to abstract code in the dma-direct (and other places in the future), however it breaks QEMU boot feature using x86_64 defconfig. That's because x86_64 defconfig has CONFIG_DMA_CMA=n so those two newly introduced helper functions are empty in their !CONFIG_DMA_CMA version, while previously the platform independent dma-direct code had fallback alloc_pages_node() and __free_pages(). So this patch fixes it by adding alloc_pages_node() and __free_pages() in the !CONFIG_DMA_CMA version of the two helper functions. Tested with below QEMU command: qemu-system-x86_64 -m 512m \ -drive file=images/x86_64/rootfs.ext4,format=raw,if=ide \ -append 'console=ttyS0 root=/dev/sda' -nographic \ -kernel arch/x86_64/boot/bzImage with the rootfs from the below link: https://github.com/ClangBuiltLinux/continuous-integration/raw/master/images/x86_64/rootfs.ext4 Fixes: fdaeec198ada ("dma-contiguous: add dma_{alloc,free}_contiguous() helpers") Reported-by: Nathan Chancellor Signed-off-by: Nicolin Chen Signed-off-by: Christoph Hellwig

dma-contiguous: add dma_{alloc,free}_contiguous() helpers

2019-06-03T14:00:07Z

Both dma_alloc_from_contiguous() and dma_release_from_contiguous() are very simply implemented, but requiring callers to pass certain parameters like count and align, and taking a boolean parameter to check __GFP_NOWARN in the allocation flags. So every function call duplicates similar work: unsigned long order = get_order(size); size_t count = size >> PAGE_SHIFT; page = dma_alloc_from_contiguous(dev, count, order, gfp & __GFP_NOWARN); [...] dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT); Additionally, as CMA can be used only in the context which permits sleeping, most of callers do a gfpflags_allow_blocking() check and a corresponding fallback allocation of normal pages upon any false result: if (gfpflags_allow_blocking(flag)) page = dma_alloc_from_contiguous(); if (!page) page = alloc_pages(); [...] if (!dma_release_from_contiguous(dev, page, count)) __free_pages(page, get_order(size)); So this patch simplifies those function calls by abstracting these operations into the two new functions: dma_{alloc,free}_contiguous. As some callers of dma_{alloc,release}_from_contiguous() might be complicated, this patch just implements these two new functions to kernel/dma/direct.c only as an initial step. Suggested-by: Christoph Hellwig Signed-off-by: Nicolin Chen Tested-by: dann frazier Signed-off-by: Christoph Hellwig

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 98

2019-05-24T15:37:54Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your optional any later version of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Richard Fontana Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520075212.713472955@linutronix.de Signed-off-by: Greg Kroah-Hartman

kernel/dma: remove unsupported gfp_mask parameter from dma_alloc_from_contiguous()

2018-08-17T23:20:32Z

The CMA memory allocator doesn't support standard gfp flags for memory allocation, so there is no point having it as a parameter for dma_alloc_from_contiguous() function. Replace it by a boolean no_warn argument, which covers all the underlaying cma_alloc() function supports. This will help to avoid giving false feeling that this function supports standard gfp flags and callers can pass __GFP_ZERO to get zeroed buffer, what has already been an issue: see commit dd65a941f6ba ("arm64: dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag"). Link: http://lkml.kernel.org/r/20180709122020eucas1p21a71b092975cb4a3b9954ffc63f699d1~-sqUFoa-h2939329393eucas1p2Y@eucas1p2.samsung.com Signed-off-by: Marek Szyprowski Acked-by: Michał Nazarewicz Acked-by: Vlastimil Babka Reviewed-by: Christoph Hellwig Cc: Laura Abbott Cc: Michal Hocko Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds