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![Jianxin Xiong](/assets/img/avatar_default.png)
Dma-buf is a standard cross-driver buffer sharing mechanism that can be used to support peer-to-peer access from RDMA devices. Device memory exported via dma-buf is associated with a file descriptor. This is passed to the user space as a property associated with the buffer allocation. When the buffer is registered as a memory region, the file descriptor is passed to the RDMA driver along with other parameters. Implement the common code for importing dma-buf object and mapping dma-buf pages. Link: https://lore.kernel.org/r/1608067636-98073-2-git-send-email-jianxin.xiong@intel.com Signed-off-by: Jianxin Xiong <jianxin.xiong@intel.com> Reviewed-by: Sean Hefty <sean.hefty@intel.com> Acked-by: Michael J. Ruhl <michael.j.ruhl@intel.com> Acked-by: Christian Koenig <christian.koenig@amd.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
191 lines
5.6 KiB
C
191 lines
5.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
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/*
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* Copyright (c) 2007 Cisco Systems. All rights reserved.
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* Copyright (c) 2020 Intel Corporation. All rights reserved.
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*/
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#ifndef IB_UMEM_H
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#define IB_UMEM_H
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#include <linux/list.h>
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#include <linux/scatterlist.h>
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#include <linux/workqueue.h>
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#include <rdma/ib_verbs.h>
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struct ib_ucontext;
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struct ib_umem_odp;
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struct dma_buf_attach_ops;
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struct ib_umem {
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struct ib_device *ibdev;
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struct mm_struct *owning_mm;
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u64 iova;
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size_t length;
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unsigned long address;
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u32 writable : 1;
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u32 is_odp : 1;
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u32 is_dmabuf : 1;
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struct work_struct work;
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struct sg_table sg_head;
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int nmap;
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unsigned int sg_nents;
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};
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struct ib_umem_dmabuf {
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struct ib_umem umem;
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struct dma_buf_attachment *attach;
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struct sg_table *sgt;
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struct scatterlist *first_sg;
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struct scatterlist *last_sg;
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unsigned long first_sg_offset;
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unsigned long last_sg_trim;
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void *private;
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};
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static inline struct ib_umem_dmabuf *to_ib_umem_dmabuf(struct ib_umem *umem)
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{
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return container_of(umem, struct ib_umem_dmabuf, umem);
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}
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/* Returns the offset of the umem start relative to the first page. */
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static inline int ib_umem_offset(struct ib_umem *umem)
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{
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return umem->address & ~PAGE_MASK;
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}
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static inline unsigned long ib_umem_dma_offset(struct ib_umem *umem,
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unsigned long pgsz)
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{
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return (sg_dma_address(umem->sg_head.sgl) + ib_umem_offset(umem)) &
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(pgsz - 1);
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}
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static inline size_t ib_umem_num_dma_blocks(struct ib_umem *umem,
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unsigned long pgsz)
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{
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return (size_t)((ALIGN(umem->iova + umem->length, pgsz) -
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ALIGN_DOWN(umem->iova, pgsz))) /
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pgsz;
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}
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static inline size_t ib_umem_num_pages(struct ib_umem *umem)
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{
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return ib_umem_num_dma_blocks(umem, PAGE_SIZE);
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}
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static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,
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struct ib_umem *umem,
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unsigned long pgsz)
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{
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__rdma_block_iter_start(biter, umem->sg_head.sgl, umem->nmap, pgsz);
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}
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/**
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* rdma_umem_for_each_dma_block - iterate over contiguous DMA blocks of the umem
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* @umem: umem to iterate over
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* @pgsz: Page size to split the list into
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*
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* pgsz must be <= PAGE_SIZE or computed by ib_umem_find_best_pgsz(). The
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* returned DMA blocks will be aligned to pgsz and span the range:
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* ALIGN_DOWN(umem->address, pgsz) to ALIGN(umem->address + umem->length, pgsz)
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*
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* Performs exactly ib_umem_num_dma_blocks() iterations.
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*/
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#define rdma_umem_for_each_dma_block(umem, biter, pgsz) \
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for (__rdma_umem_block_iter_start(biter, umem, pgsz); \
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__rdma_block_iter_next(biter);)
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#ifdef CONFIG_INFINIBAND_USER_MEM
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struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
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size_t size, int access);
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void ib_umem_release(struct ib_umem *umem);
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int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
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size_t length);
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unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
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unsigned long pgsz_bitmap,
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unsigned long virt);
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/**
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* ib_umem_find_best_pgoff - Find best HW page size
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*
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* @umem: umem struct
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* @pgsz_bitmap bitmap of HW supported page sizes
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* @pgoff_bitmask: Mask of bits that can be represented with an offset
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*
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* This is very similar to ib_umem_find_best_pgsz() except instead of accepting
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* an IOVA it accepts a bitmask specifying what address bits can be represented
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* with a page offset.
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*
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* For instance if the HW has multiple page sizes, requires 64 byte alignemnt,
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* and can support aligned offsets up to 4032 then pgoff_bitmask would be
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* "111111000000".
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*
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* If the pgoff_bitmask requires either alignment in the low bit or an
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* unavailable page size for the high bits, this function returns 0.
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*/
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static inline unsigned long ib_umem_find_best_pgoff(struct ib_umem *umem,
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unsigned long pgsz_bitmap,
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u64 pgoff_bitmask)
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{
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struct scatterlist *sg = umem->sg_head.sgl;
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dma_addr_t dma_addr;
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dma_addr = sg_dma_address(sg) + (umem->address & ~PAGE_MASK);
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return ib_umem_find_best_pgsz(umem, pgsz_bitmap,
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dma_addr & pgoff_bitmask);
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}
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struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
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unsigned long offset, size_t size,
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int fd, int access,
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const struct dma_buf_attach_ops *ops);
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int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf);
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void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf);
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void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf);
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#else /* CONFIG_INFINIBAND_USER_MEM */
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#include <linux/err.h>
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static inline struct ib_umem *ib_umem_get(struct ib_device *device,
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unsigned long addr, size_t size,
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int access)
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{
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return ERR_PTR(-EOPNOTSUPP);
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}
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static inline void ib_umem_release(struct ib_umem *umem) { }
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static inline int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
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size_t length) {
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return -EOPNOTSUPP;
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}
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static inline unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
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unsigned long pgsz_bitmap,
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unsigned long virt)
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{
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return 0;
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}
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static inline unsigned long ib_umem_find_best_pgoff(struct ib_umem *umem,
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unsigned long pgsz_bitmap,
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u64 pgoff_bitmask)
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{
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return 0;
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}
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static inline
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struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
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unsigned long offset,
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size_t size, int fd,
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int access,
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struct dma_buf_attach_ops *ops)
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{
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return ERR_PTR(-EOPNOTSUPP);
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}
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static inline int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
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{
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return -EOPNOTSUPP;
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}
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static inline void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf) { }
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static inline void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf) { }
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#endif /* CONFIG_INFINIBAND_USER_MEM */
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#endif /* IB_UMEM_H */
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