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->revoked)
27 return -EINVAL;
28
29 if (umem_dmabuf->sgt)
30 goto wait_fence;
31
32 sgt = dma_buf_map_attachment(umem_dmabuf->attach,
33 DMA_BIDIRECTIONAL);
34 if (IS_ERR(ptr: sgt))
35 return PTR_ERR(ptr: sgt);
36
37 /* modify the sg list in-place to match umem address and length */
38
39 start = ALIGN_DOWN(umem_dmabuf->umem.address, PAGE_SIZE);
40 end = ALIGN(umem_dmabuf->umem.address + umem_dmabuf->umem.length,
41 PAGE_SIZE);
42 for_each_sgtable_dma_sg(sgt, sg, i) {
43 if (start < cur + sg_dma_len(sg) && cur < end)
44 nmap++;
45 if (cur <= start && start < cur + sg_dma_len(sg)) {
46 unsigned long offset = start - cur;
47
48 umem_dmabuf->first_sg = sg;
49 umem_dmabuf->first_sg_offset = offset;
50 sg_dma_address(sg) += offset;
51 sg_dma_len(sg) -= offset;
52 cur += offset;
53 }
54 if (cur < end && end <= cur + sg_dma_len(sg)) {
55 unsigned long trim = cur + sg_dma_len(sg) - end;
56
57 umem_dmabuf->last_sg = sg;
58 umem_dmabuf->last_sg_trim = trim;
59 sg_dma_len(sg) -= trim;
60 break;
61 }
62 cur += sg_dma_len(sg);
63 }
64
65 umem_dmabuf->umem.sgt_append.sgt.sgl = umem_dmabuf->first_sg;
66 umem_dmabuf->umem.sgt_append.sgt.nents = nmap;
67 umem_dmabuf->sgt = sgt;
68
69wait_fence:
70 /*
71 * Although the sg list is valid now, the content of the pages
72 * may be not up-to-date. Wait for the exporter to finish
73 * the migration.
74 */
75 ret = dma_resv_wait_timeout(obj: umem_dmabuf->attach->dmabuf->resv,
76 usage: DMA_RESV_USAGE_KERNEL,
77 intr: false, MAX_SCHEDULE_TIMEOUT);
78 if (ret < 0)
79 return ret;
80 if (ret == 0)
81 return -ETIMEDOUT;
82 return 0;
83}
84EXPORT_SYMBOL(ib_umem_dmabuf_map_pages);
85
86void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf)
87{
88 dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
89
90 if (!umem_dmabuf->sgt)
91 return;
92
93 /* retore the original sg list */
94 if (umem_dmabuf->first_sg) {
95 sg_dma_address(umem_dmabuf->first_sg) -=
96 umem_dmabuf->first_sg_offset;
97 sg_dma_len(umem_dmabuf->first_sg) +=
98 umem_dmabuf->first_sg_offset;
99 umem_dmabuf->first_sg = NULL;
100 umem_dmabuf->first_sg_offset = 0;
101 }
102 if (umem_dmabuf->last_sg) {
103 sg_dma_len(umem_dmabuf->last_sg) +=
104 umem_dmabuf->last_sg_trim;
105 umem_dmabuf->last_sg = NULL;
106 umem_dmabuf->last_sg_trim = 0;
107 }
108
109 dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
110 DMA_BIDIRECTIONAL);
111
112 umem_dmabuf->sgt = NULL;
113}
114EXPORT_SYMBOL(ib_umem_dmabuf_unmap_pages);
115
116static struct ib_umem_dmabuf *
117ib_umem_dmabuf_get_with_dma_device(struct ib_device *device,
118 struct device *dma_device,
119 unsigned long offset, size_t size,
120 int fd, int access,
121 const struct dma_buf_attach_ops *ops)
122{
123 struct dma_buf *dmabuf;
124 struct ib_umem_dmabuf *umem_dmabuf;
125 struct ib_umem *umem;
126 unsigned long end;
127 struct ib_umem_dmabuf *ret = ERR_PTR(error: -EINVAL);
128
129 if (check_add_overflow(offset, (unsigned long)size, &end))
130 return ret;
131
132 if (unlikely(!ops || !ops->move_notify))
133 return ret;
134
135 dmabuf = dma_buf_get(fd);
136 if (IS_ERR(ptr: dmabuf))
137 return ERR_CAST(ptr: dmabuf);
138
139 if (dmabuf->size < end)
140 goto out_release_dmabuf;
141
142 umem_dmabuf = kzalloc(sizeof(*umem_dmabuf), GFP_KERNEL);
143 if (!umem_dmabuf) {
144 ret = ERR_PTR(error: -ENOMEM);
145 goto out_release_dmabuf;
146 }
147
148 umem = &umem_dmabuf->umem;
149 umem->ibdev = device;
150 umem->length = size;
151 umem->address = offset;
152 umem->writable = ib_access_writable(access_flags: access);
153 umem->is_dmabuf = 1;
154
155 if (!ib_umem_num_pages(umem))
156 goto out_free_umem;
157
158 umem_dmabuf->attach = dma_buf_dynamic_attach(
159 dmabuf,
160 dev: dma_device,
161 importer_ops: ops,
162 importer_priv: umem_dmabuf);
163 if (IS_ERR(ptr: umem_dmabuf->attach)) {
164 ret = ERR_CAST(ptr: umem_dmabuf->attach);
165 goto out_free_umem;
166 }
167 return umem_dmabuf;
168
169out_free_umem:
170 kfree(objp: umem_dmabuf);
171
172out_release_dmabuf:
173 dma_buf_put(dmabuf);
174 return ret;
175}
176
177struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
178 unsigned long offset, size_t size,
179 int fd, int access,
180 const struct dma_buf_attach_ops *ops)
181{
182 return ib_umem_dmabuf_get_with_dma_device(device, dma_device: device->dma_device,
183 offset, size, fd, access, ops);
184}
185EXPORT_SYMBOL(ib_umem_dmabuf_get);
186
187static void
188ib_umem_dmabuf_unsupported_move_notify(struct dma_buf_attachment *attach)
189{
190 struct ib_umem_dmabuf *umem_dmabuf = attach->importer_priv;
191
192 ibdev_warn_ratelimited(umem_dmabuf->umem.ibdev,
193 "Invalidate callback should not be called when memory is pinned\n");
194}
195
196static struct dma_buf_attach_ops ib_umem_dmabuf_attach_pinned_ops = {
197 .allow_peer2peer = true,
198 .move_notify = ib_umem_dmabuf_unsupported_move_notify,
199};
200
201struct ib_umem_dmabuf *
202ib_umem_dmabuf_get_pinned_with_dma_device(struct ib_device *device,
203 struct device *dma_device,
204 unsigned long offset, size_t size,
205 int fd, int access)
206{
207 struct ib_umem_dmabuf *umem_dmabuf;
208 int err;
209
210 umem_dmabuf = ib_umem_dmabuf_get_with_dma_device(device, dma_device, offset,
211 size, fd, access,
212 ops: &ib_umem_dmabuf_attach_pinned_ops);
213 if (IS_ERR(ptr: umem_dmabuf))
214 return umem_dmabuf;
215
216 dma_resv_lock(obj: umem_dmabuf->attach->dmabuf->resv, NULL);
217 err = dma_buf_pin(attach: umem_dmabuf->attach);
218 if (err)
219 goto err_release;
220 umem_dmabuf->pinned = 1;
221
222 err = ib_umem_dmabuf_map_pages(umem_dmabuf);
223 if (err)
224 goto err_unpin;
225 dma_resv_unlock(obj: umem_dmabuf->attach->dmabuf->resv);
226
227 return umem_dmabuf;
228
229err_unpin:
230 dma_buf_unpin(attach: umem_dmabuf->attach);
231err_release:
232 dma_resv_unlock(obj: umem_dmabuf->attach->dmabuf->resv);
233 ib_umem_release(umem: &umem_dmabuf->umem);
234 return ERR_PTR(error: err);
235}
236EXPORT_SYMBOL(ib_umem_dmabuf_get_pinned_with_dma_device);
237
238struct ib_umem_dmabuf *ib_umem_dmabuf_get_pinned(struct ib_device *device,
239 unsigned long offset,
240 size_t size, int fd,
241 int access)
242{
243 return ib_umem_dmabuf_get_pinned_with_dma_device(device, device->dma_device,
244 offset, size, fd, access);
245}
246EXPORT_SYMBOL(ib_umem_dmabuf_get_pinned);
247
248void ib_umem_dmabuf_revoke(struct ib_umem_dmabuf *umem_dmabuf)
249{
250 struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
251
252 dma_resv_lock(obj: dmabuf->resv, NULL);
253 if (umem_dmabuf->revoked)
254 goto end;
255 ib_umem_dmabuf_unmap_pages(umem_dmabuf);
256 if (umem_dmabuf->pinned) {
257 dma_buf_unpin(attach: umem_dmabuf->attach);
258 umem_dmabuf->pinned = 0;
259 }
260 umem_dmabuf->revoked = 1;
261end:
262 dma_resv_unlock(obj: dmabuf->resv);
263}
264EXPORT_SYMBOL(ib_umem_dmabuf_revoke);
265
266void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf)
267{
268 struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
269
270 ib_umem_dmabuf_revoke(umem_dmabuf);
271
272 dma_buf_detach(dmabuf, attach: umem_dmabuf->attach);
273 dma_buf_put(dmabuf);
274 kfree(objp: umem_dmabuf);
275}
276

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