1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
3 *
4 * Copyright (c) 2005 Topspin Communications. All rights reserved.
5 * Copyright (c) 2005 Cisco Systems. All rights reserved.
6 * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
7 *
8 * This software is available to you under a choice of one of two
9 * licenses. You may choose to be licensed under the terms of the GNU
10 * General Public License (GPL) Version 2, available from the file
11 * COPYING in the main directory of this source tree, or the
12 * OpenIB.org BSD license below:
13 *
14 * Redistribution and use in source and binary forms, with or
15 * without modification, are permitted provided that the following
16 * conditions are met:
17 *
18 * - Redistributions of source code must retain the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer.
21 *
22 * - Redistributions in binary form must reproduce the above
23 * copyright notice, this list of conditions and the following
24 * disclaimer in the documentation and/or other materials
25 * provided with the distribution.
26 *
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
28 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
29 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
30 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
31 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
32 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
33 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
34 * SOFTWARE.
35 */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39
40 #define LINUXKPI_PARAM_PREFIX ibcore_
41
42 #include <linux/mm.h>
43 #include <linux/dma-mapping.h>
44 #include <linux/sched.h>
45 #include <linux/slab.h>
46 #include <linux/wait.h>
47 #include <rdma/ib_umem_odp.h>
48
49 #include "uverbs.h"
50
51 #include <sys/priv.h>
52
53 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
54 {
55 struct scatterlist *sg;
56 struct page *page;
57 int i;
58
59 if (umem->nmap > 0)
60 ib_dma_unmap_sg(dev, umem->sg_head.sgl,
61 umem->nmap,
62 DMA_BIDIRECTIONAL);
63
64 for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
65
66 page = sg_page(sg);
67 put_page(page);
68 }
69
70 sg_free_table(&umem->sg_head);
71 return;
72
73 }
74
75 /**
76 * ib_umem_get - Pin and DMA map userspace memory.
77 *
78 * If access flags indicate ODP memory, avoid pinning. Instead, stores
79 * the mm for future page fault handling in conjunction with MMU notifiers.
80 *
81 * @context: userspace context to pin memory for
82 * @addr: userspace virtual address to start at
83 * @size: length of region to pin
84 * @access: IB_ACCESS_xxx flags for memory being pinned
85 * @dmasync: flush in-flight DMA when the memory region is written
86 */
87 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
88 size_t size, int access, int dmasync)
89 {
90 struct ib_umem *umem;
91 struct page **page_list;
92 struct vm_area_struct **vma_list;
93 unsigned long locked;
94 unsigned long cur_base;
95 unsigned long npages;
96 int ret;
97 int i;
98 struct dma_attrs dma_attrs = { 0 };
99 struct scatterlist *sg, *sg_list_start;
100 int need_release = 0;
101 unsigned int gup_flags = FOLL_WRITE;
102
103 if (dmasync)
104 dma_attrs.flags |= DMA_ATTR_WRITE_BARRIER;
105
106 if (!size)
107 return ERR_PTR(-EINVAL);
108
109 /*
110 * If the combination of the addr and size requested for this memory
111 * region causes an integer overflow, return error.
112 */
113 if (((addr + size) < addr) ||
114 PAGE_ALIGN(addr + size) < (addr + size))
115 return ERR_PTR(-EINVAL);
116
117 if (priv_check(curthread, PRIV_VM_MLOCK) != 0)
118 return ERR_PTR(-EPERM);
119
120 umem = kzalloc(sizeof *umem, GFP_KERNEL);
121 if (!umem)
122 return ERR_PTR(-ENOMEM);
123
124 umem->context = context;
125 umem->length = size;
126 umem->address = addr;
127 umem->page_size = PAGE_SIZE;
128 umem->pid = get_pid(task_pid(current));
129 /*
130 * We ask for writable memory if any of the following
131 * access flags are set. "Local write" and "remote write"
132 * obviously require write access. "Remote atomic" can do
133 * things like fetch and add, which will modify memory, and
134 * "MW bind" can change permissions by binding a window.
135 */
136 umem->writable = !!(access &
137 (IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE |
138 IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
139
140 if (access & IB_ACCESS_ON_DEMAND) {
141 ret = ib_umem_odp_get(context, umem);
142 if (ret) {
143 kfree(umem);
144 return ERR_PTR(ret);
145 }
146 return umem;
147 }
148
149 umem->odp_data = NULL;
150
151 page_list = (struct page **) __get_free_page(GFP_KERNEL);
152 if (!page_list) {
153 kfree(umem);
154 return ERR_PTR(-ENOMEM);
155 }
156
157 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
158
159 npages = ib_umem_num_pages(umem);
160
161 down_write(¤t->mm->mmap_sem);
162
163 locked = npages + current->mm->pinned_vm;
164
165 cur_base = addr & PAGE_MASK;
166
167 if (npages == 0 || npages > UINT_MAX) {
168 ret = -EINVAL;
169 goto out;
170 }
171
172 ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
173 if (ret)
174 goto out;
175
176 if (!umem->writable)
177 gup_flags |= FOLL_FORCE;
178
179 need_release = 1;
180 sg_list_start = umem->sg_head.sgl;
181
182 while (npages) {
183 ret = get_user_pages(cur_base,
184 min_t(unsigned long, npages,
185 PAGE_SIZE / sizeof (struct page *)),
186 gup_flags, page_list, vma_list);
187
188 if (ret < 0)
189 goto out;
190
191 umem->npages += ret;
192 cur_base += ret * PAGE_SIZE;
193 npages -= ret;
194
195 for_each_sg(sg_list_start, sg, ret, i) {
196 sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
197 }
198
199 /* preparing for next loop */
200 sg_list_start = sg;
201 }
202
203 umem->nmap = ib_dma_map_sg_attrs(context->device,
204 umem->sg_head.sgl,
205 umem->npages,
206 DMA_BIDIRECTIONAL,
207 &dma_attrs);
208
209 if (umem->nmap <= 0) {
210 ret = -ENOMEM;
211 goto out;
212 }
213
214 ret = 0;
215
216 out:
217 if (ret < 0) {
218 if (need_release)
219 __ib_umem_release(context->device, umem, 0);
220 put_pid(umem->pid);
221 kfree(umem);
222 } else
223 current->mm->pinned_vm = locked;
224
225 up_write(¤t->mm->mmap_sem);
226 if (vma_list)
227 free_page((unsigned long) vma_list);
228 free_page((unsigned long) page_list);
229
230 return ret < 0 ? ERR_PTR(ret) : umem;
231 }
232 EXPORT_SYMBOL(ib_umem_get);
233
234 static void ib_umem_account(struct work_struct *work)
235 {
236 struct ib_umem *umem = container_of(work, struct ib_umem, work);
237
238 down_write(&umem->mm->mmap_sem);
239 umem->mm->pinned_vm -= umem->diff;
240 up_write(&umem->mm->mmap_sem);
241 mmput(umem->mm);
242 kfree(umem);
243 }
244
245 /**
246 * ib_umem_release - release memory pinned with ib_umem_get
247 * @umem: umem struct to release
248 */
249 void ib_umem_release(struct ib_umem *umem)
250 {
251 struct mm_struct *mm;
252 struct task_struct *task;
253 unsigned long diff;
254
255 if (!umem)
256 return;
257
258 if (umem->odp_data) {
259 ib_umem_odp_release(umem);
260 return;
261 }
262
263 __ib_umem_release(umem->context->device, umem, 1);
264
265 task = get_pid_task(umem->pid, PIDTYPE_PID);
266 put_pid(umem->pid);
267 if (!task)
268 goto out;
269 mm = get_task_mm(task);
270 put_task_struct(task);
271 if (!mm)
272 goto out;
273
274 diff = ib_umem_num_pages(umem);
275
276 /*
277 * We may be called with the mm's mmap_sem already held. This
278 * can happen when a userspace munmap() is the call that drops
279 * the last reference to our file and calls our release
280 * method. If there are memory regions to destroy, we'll end
281 * up here and not be able to take the mmap_sem. In that case
282 * we defer the vm_locked accounting to the system workqueue.
283 */
284 if (umem->context->closing) {
285 if (!down_write_trylock(&mm->mmap_sem)) {
286 INIT_WORK(&umem->work, ib_umem_account);
287 umem->mm = mm;
288 umem->diff = diff;
289
290 queue_work(ib_wq, &umem->work);
291 return;
292 }
293 } else
294 down_write(&mm->mmap_sem);
295
296 mm->pinned_vm -= diff;
297 up_write(&mm->mmap_sem);
298 mmput(mm);
299 out:
300 kfree(umem);
301 }
302 EXPORT_SYMBOL(ib_umem_release);
303
304 int ib_umem_page_count(struct ib_umem *umem)
305 {
306 int shift;
307 int i;
308 int n;
309 struct scatterlist *sg;
310
311 if (umem->odp_data)
312 return ib_umem_num_pages(umem);
313
314 shift = ilog2(umem->page_size);
315
316 n = 0;
317 for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
318 n += sg_dma_len(sg) >> shift;
319
320 return n;
321 }
322 EXPORT_SYMBOL(ib_umem_page_count);
323
324 /*
325 * Copy from the given ib_umem's pages to the given buffer.
326 *
327 * umem - the umem to copy from
328 * offset - offset to start copying from
329 * dst - destination buffer
330 * length - buffer length
331 *
332 * Returns 0 on success, or an error code.
333 */
334 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
335 size_t length)
336 {
337 size_t end = offset + length;
338 int ret;
339
340 if (offset > umem->length || length > umem->length - offset) {
341 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n",
342 offset, umem->length, end);
343 return -EINVAL;
344 }
345
346 #ifdef __linux__
347 ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length,
348 offset + ib_umem_offset(umem));
349 #else
350 ret = 0;
351 #endif
352 if (ret < 0)
353 return ret;
354 else if (ret != length)
355 return -EINVAL;
356 else
357 return 0;
358 }
359 EXPORT_SYMBOL(ib_umem_copy_from);
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