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#include <linux/module.h>
10
11#include "uverbs.h"
12
13MODULE_IMPORT_NS(DMA_BUF);
14
15int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
16{
17 struct sg_table *sgt;
18 struct scatterlist *sg;
19 unsigned long start, end, cur = 0;
20 unsigned int nmap = 0;
21 long ret;
22 int i;
23
24 dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
25
26 if (umem_dmabuf->sgt)
27 goto wait_fence;
28
29 sgt = dma_buf_map_attachment(umem_dmabuf->attach,
30 DMA_BIDIRECTIONAL);
31 if (IS_ERR(ptr: sgt))
32 return PTR_ERR(ptr: sgt);
33
34 /* modify the sg list in-place to match umem address and length */
35
36 start = ALIGN_DOWN(umem_dmabuf->umem.address, PAGE_SIZE);
37 end = ALIGN(umem_dmabuf->umem.address + umem_dmabuf->umem.length,
38 PAGE_SIZE);
39 for_each_sgtable_dma_sg(sgt, sg, i) {
40 if (start < cur + sg_dma_len(sg) && cur < end)
41 nmap++;
42 if (cur <= start && start < cur + sg_dma_len(sg)) {
43 unsigned long offset = start - cur;
44
45 umem_dmabuf->first_sg = sg;
46 umem_dmabuf->first_sg_offset = offset;
47 sg_dma_address(sg) += offset;
48 sg_dma_len(sg) -= offset;
49 cur += offset;
50 }
51 if (cur < end && end <= cur + sg_dma_len(sg)) {
52 unsigned long trim = cur + sg_dma_len(sg) - end;
53
54 umem_dmabuf->last_sg = sg;
55 umem_dmabuf->last_sg_trim = trim;
56 sg_dma_len(sg) -= trim;
57 break;
58 }
59 cur += sg_dma_len(sg);
60 }
61
62 umem_dmabuf->umem.sgt_append.sgt.sgl = umem_dmabuf->first_sg;
63 umem_dmabuf->umem.sgt_append.sgt.nents = nmap;
64 umem_dmabuf->sgt = sgt;
65
66wait_fence:
67 /*
68 * Although the sg list is valid now, the content of the pages
69 * may be not up-to-date. Wait for the exporter to finish
70 * the migration.
71 */
72 ret = dma_resv_wait_timeout(obj: umem_dmabuf->attach->dmabuf->resv,
73 usage: DMA_RESV_USAGE_KERNEL,
74 intr: false, MAX_SCHEDULE_TIMEOUT);
75 if (ret < 0)
76 return ret;
77 if (ret == 0)
78 return -ETIMEDOUT;
79 return 0;
80}
81EXPORT_SYMBOL(ib_umem_dmabuf_map_pages);
82
83void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf)
84{
85 dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
86
87 if (!umem_dmabuf->sgt)
88 return;
89
90 /* retore the original sg list */
91 if (umem_dmabuf->first_sg) {
92 sg_dma_address(umem_dmabuf->first_sg) -=
93 umem_dmabuf->first_sg_offset;
94 sg_dma_len(umem_dmabuf->first_sg) +=
95 umem_dmabuf->first_sg_offset;
96 umem_dmabuf->first_sg = NULL;
97 umem_dmabuf->first_sg_offset = 0;
98 }
99 if (umem_dmabuf->last_sg) {
100 sg_dma_len(umem_dmabuf->last_sg) +=
101 umem_dmabuf->last_sg_trim;
102 umem_dmabuf->last_sg = NULL;
103 umem_dmabuf->last_sg_trim = 0;
104 }
105
106 dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
107 DMA_BIDIRECTIONAL);
108
109 umem_dmabuf->sgt = NULL;
110}
111EXPORT_SYMBOL(ib_umem_dmabuf_unmap_pages);
112
113struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
114 unsigned long offset, size_t size,
115 int fd, int access,
116 const struct dma_buf_attach_ops *ops)
117{
118 struct dma_buf *dmabuf;
119 struct ib_umem_dmabuf *umem_dmabuf;
120 struct ib_umem *umem;
121 unsigned long end;
122 struct ib_umem_dmabuf *ret = ERR_PTR(error: -EINVAL);
123
124 if (check_add_overflow(offset, (unsigned long)size, &end))
125 return ret;
126
127 if (unlikely(!ops || !ops->move_notify))
128 return ret;
129
130 dmabuf = dma_buf_get(fd);
131 if (IS_ERR(ptr: dmabuf))
132 return ERR_CAST(ptr: dmabuf);
133
134 if (dmabuf->size < end)
135 goto out_release_dmabuf;
136
137 umem_dmabuf = kzalloc(size: sizeof(*umem_dmabuf), GFP_KERNEL);
138 if (!umem_dmabuf) {
139 ret = ERR_PTR(error: -ENOMEM);
140 goto out_release_dmabuf;
141 }
142
143 umem = &umem_dmabuf->umem;
144 umem->ibdev = device;
145 umem->length = size;
146 umem->address = offset;
147 umem->writable = ib_access_writable(access_flags: access);
148 umem->is_dmabuf = 1;
149
150 if (!ib_umem_num_pages(umem))
151 goto out_free_umem;
152
153 umem_dmabuf->attach = dma_buf_dynamic_attach(
154 dmabuf,
155 dev: device->dma_device,
156 importer_ops: ops,
157 importer_priv: umem_dmabuf);
158 if (IS_ERR(ptr: umem_dmabuf->attach)) {
159 ret = ERR_CAST(ptr: umem_dmabuf->attach);
160 goto out_free_umem;
161 }
162 return umem_dmabuf;
163
164out_free_umem:
165 kfree(objp: umem_dmabuf);
166
167out_release_dmabuf:
168 dma_buf_put(dmabuf);
169 return ret;
170}
171EXPORT_SYMBOL(ib_umem_dmabuf_get);
172
173static void
174ib_umem_dmabuf_unsupported_move_notify(struct dma_buf_attachment *attach)
175{
176 struct ib_umem_dmabuf *umem_dmabuf = attach->importer_priv;
177
178 ibdev_warn_ratelimited(umem_dmabuf->umem.ibdev,
179 "Invalidate callback should not be called when memory is pinned\n");
180}
181
182static struct dma_buf_attach_ops ib_umem_dmabuf_attach_pinned_ops = {
183 .allow_peer2peer = true,
184 .move_notify = ib_umem_dmabuf_unsupported_move_notify,
185};
186
187struct ib_umem_dmabuf *ib_umem_dmabuf_get_pinned(struct ib_device *device,
188 unsigned long offset,
189 size_t size, int fd,
190 int access)
191{
192 struct ib_umem_dmabuf *umem_dmabuf;
193 int err;
194
195 umem_dmabuf = ib_umem_dmabuf_get(device, offset, size, fd, access,
196 &ib_umem_dmabuf_attach_pinned_ops);
197 if (IS_ERR(ptr: umem_dmabuf))
198 return umem_dmabuf;
199
200 dma_resv_lock(obj: umem_dmabuf->attach->dmabuf->resv, NULL);
201 err = dma_buf_pin(attach: umem_dmabuf->attach);
202 if (err)
203 goto err_release;
204 umem_dmabuf->pinned = 1;
205
206 err = ib_umem_dmabuf_map_pages(umem_dmabuf);
207 if (err)
208 goto err_unpin;
209 dma_resv_unlock(obj: umem_dmabuf->attach->dmabuf->resv);
210
211 return umem_dmabuf;
212
213err_unpin:
214 dma_buf_unpin(attach: umem_dmabuf->attach);
215err_release:
216 dma_resv_unlock(obj: umem_dmabuf->attach->dmabuf->resv);
217 ib_umem_release(umem: &umem_dmabuf->umem);
218 return ERR_PTR(error: err);
219}
220EXPORT_SYMBOL(ib_umem_dmabuf_get_pinned);
221
222void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf)
223{
224 struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
225
226 dma_resv_lock(obj: dmabuf->resv, NULL);
227 ib_umem_dmabuf_unmap_pages(umem_dmabuf);
228 if (umem_dmabuf->pinned)
229 dma_buf_unpin(attach: umem_dmabuf->attach);
230 dma_resv_unlock(obj: dmabuf->resv);
231
232 dma_buf_detach(dmabuf, attach: umem_dmabuf->attach);
233 dma_buf_put(dmabuf);
234 kfree(objp: umem_dmabuf);
235}
236

source code of linux/drivers/infiniband/core/umem_dmabuf.c