1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) 2 /* 3 * Copyright (c) 2020 Intel Corporation. All rights reserved. 4 */ 5 6 #include <linux/dma-buf.h> 7 #include <linux/dma-resv.h> 8 #include <linux/dma-mapping.h> 9 10 #include "uverbs.h" 11 12 int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf) 13 { 14 struct sg_table *sgt; 15 struct scatterlist *sg; 16 struct dma_fence *fence; 17 unsigned long start, end, cur = 0; 18 unsigned int nmap = 0; 19 int i; 20 21 dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv); 22 23 if (umem_dmabuf->sgt) 24 goto wait_fence; 25 26 sgt = dma_buf_map_attachment(umem_dmabuf->attach, DMA_BIDIRECTIONAL); 27 if (IS_ERR(sgt)) 28 return PTR_ERR(sgt); 29 30 /* modify the sg list in-place to match umem address and length */ 31 32 start = ALIGN_DOWN(umem_dmabuf->umem.address, PAGE_SIZE); 33 end = ALIGN(umem_dmabuf->umem.address + umem_dmabuf->umem.length, 34 PAGE_SIZE); 35 for_each_sgtable_dma_sg(sgt, sg, i) { 36 if (start < cur + sg_dma_len(sg) && cur < end) 37 nmap++; 38 if (cur <= start && start < cur + sg_dma_len(sg)) { 39 unsigned long offset = start - cur; 40 41 umem_dmabuf->first_sg = sg; 42 umem_dmabuf->first_sg_offset = offset; 43 sg_dma_address(sg) += offset; 44 sg_dma_len(sg) -= offset; 45 cur += offset; 46 } 47 if (cur < end && end <= cur + sg_dma_len(sg)) { 48 unsigned long trim = cur + sg_dma_len(sg) - end; 49 50 umem_dmabuf->last_sg = sg; 51 umem_dmabuf->last_sg_trim = trim; 52 sg_dma_len(sg) -= trim; 53 break; 54 } 55 cur += sg_dma_len(sg); 56 } 57 58 umem_dmabuf->umem.sgt_append.sgt.sgl = umem_dmabuf->first_sg; 59 umem_dmabuf->umem.sgt_append.sgt.nents = nmap; 60 umem_dmabuf->sgt = sgt; 61 62 wait_fence: 63 /* 64 * Although the sg list is valid now, the content of the pages 65 * may be not up-to-date. Wait for the exporter to finish 66 * the migration. 67 */ 68 fence = dma_resv_excl_fence(umem_dmabuf->attach->dmabuf->resv); 69 if (fence) 70 return dma_fence_wait(fence, false); 71 72 return 0; 73 } 74 EXPORT_SYMBOL(ib_umem_dmabuf_map_pages); 75 76 void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf) 77 { 78 dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv); 79 80 if (!umem_dmabuf->sgt) 81 return; 82 83 /* retore the original sg list */ 84 if (umem_dmabuf->first_sg) { 85 sg_dma_address(umem_dmabuf->first_sg) -= 86 umem_dmabuf->first_sg_offset; 87 sg_dma_len(umem_dmabuf->first_sg) += 88 umem_dmabuf->first_sg_offset; 89 umem_dmabuf->first_sg = NULL; 90 umem_dmabuf->first_sg_offset = 0; 91 } 92 if (umem_dmabuf->last_sg) { 93 sg_dma_len(umem_dmabuf->last_sg) += 94 umem_dmabuf->last_sg_trim; 95 umem_dmabuf->last_sg = NULL; 96 umem_dmabuf->last_sg_trim = 0; 97 } 98 99 dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt, 100 DMA_BIDIRECTIONAL); 101 102 umem_dmabuf->sgt = NULL; 103 } 104 EXPORT_SYMBOL(ib_umem_dmabuf_unmap_pages); 105 106 struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device, 107 unsigned long offset, size_t size, 108 int fd, int access, 109 const struct dma_buf_attach_ops *ops) 110 { 111 struct dma_buf *dmabuf; 112 struct ib_umem_dmabuf *umem_dmabuf; 113 struct ib_umem *umem; 114 unsigned long end; 115 struct ib_umem_dmabuf *ret = ERR_PTR(-EINVAL); 116 117 if (check_add_overflow(offset, (unsigned long)size, &end)) 118 return ret; 119 120 if (unlikely(!ops || !ops->move_notify)) 121 return ret; 122 123 dmabuf = dma_buf_get(fd); 124 if (IS_ERR(dmabuf)) 125 return ERR_CAST(dmabuf); 126 127 if (dmabuf->size < end) 128 goto out_release_dmabuf; 129 130 umem_dmabuf = kzalloc(sizeof(*umem_dmabuf), GFP_KERNEL); 131 if (!umem_dmabuf) { 132 ret = ERR_PTR(-ENOMEM); 133 goto out_release_dmabuf; 134 } 135 136 umem = &umem_dmabuf->umem; 137 umem->ibdev = device; 138 umem->length = size; 139 umem->address = offset; 140 umem->writable = ib_access_writable(access); 141 umem->is_dmabuf = 1; 142 143 if (!ib_umem_num_pages(umem)) 144 goto out_free_umem; 145 146 umem_dmabuf->attach = dma_buf_dynamic_attach( 147 dmabuf, 148 device->dma_device, 149 ops, 150 umem_dmabuf); 151 if (IS_ERR(umem_dmabuf->attach)) { 152 ret = ERR_CAST(umem_dmabuf->attach); 153 goto out_free_umem; 154 } 155 return umem_dmabuf; 156 157 out_free_umem: 158 kfree(umem_dmabuf); 159 160 out_release_dmabuf: 161 dma_buf_put(dmabuf); 162 return ret; 163 } 164 EXPORT_SYMBOL(ib_umem_dmabuf_get); 165 166 void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf) 167 { 168 struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf; 169 170 dma_resv_lock(dmabuf->resv, NULL); 171 ib_umem_dmabuf_unmap_pages(umem_dmabuf); 172 dma_resv_unlock(dmabuf->resv); 173 174 dma_buf_detach(dmabuf, umem_dmabuf->attach); 175 dma_buf_put(dmabuf); 176 kfree(umem_dmabuf); 177 } 178