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(sgt))
32		return PTR_ERR(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(umem_dmabuf->attach->dmabuf->resv,
73				     DMA_RESV_USAGE_KERNEL,
74				     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(-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(dmabuf))
132		return ERR_CAST(dmabuf);
133
134	if (dmabuf->size < end)
135		goto out_release_dmabuf;
136
137	umem_dmabuf = kzalloc(sizeof(*umem_dmabuf), GFP_KERNEL);
138	if (!umem_dmabuf) {
139		ret = ERR_PTR(-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);
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					device->dma_device,
156					ops,
157					umem_dmabuf);
158	if (IS_ERR(umem_dmabuf->attach)) {
159		ret = ERR_CAST(umem_dmabuf->attach);
160		goto out_free_umem;
161	}
162	return umem_dmabuf;
163
164out_free_umem:
165	kfree(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(umem_dmabuf))
198		return umem_dmabuf;
199
200	dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
201	err = dma_buf_pin(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(umem_dmabuf->attach->dmabuf->resv);
210
211	return umem_dmabuf;
212
213err_unpin:
214	dma_buf_unpin(umem_dmabuf->attach);
215err_release:
216	dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
217	ib_umem_release(&umem_dmabuf->umem);
218	return ERR_PTR(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(dmabuf->resv, NULL);
227	ib_umem_dmabuf_unmap_pages(umem_dmabuf);
228	if (umem_dmabuf->pinned)
229		dma_buf_unpin(umem_dmabuf->attach);
230	dma_resv_unlock(dmabuf->resv);
231
232	dma_buf_detach(dmabuf, umem_dmabuf->attach);
233	dma_buf_put(dmabuf);
234	kfree(umem_dmabuf);
235}
236