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 #define LINUXKPI_PARAM_PREFIX ibcore_
39
40 #include <linux/mm.h>
41 #include <linux/dma-mapping.h>
42 #include <linux/sched.h>
43 #include <linux/slab.h>
44 #include <linux/wait.h>
45 #include <rdma/ib_umem_odp.h>
46
47 #include "uverbs.h"
48
49 #include <sys/priv.h>
50
__ib_umem_release(struct ib_device * dev,struct ib_umem * umem,int dirty)51 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
52 {
53 struct scatterlist *sg;
54 struct page *page;
55 int i;
56
57 if (umem->nmap > 0)
58 ib_dma_unmap_sg(dev, umem->sg_head.sgl,
59 umem->nmap,
60 DMA_BIDIRECTIONAL);
61
62 for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
63
64 page = sg_page(sg);
65 put_page(page);
66 }
67
68 sg_free_table(&umem->sg_head);
69 return;
70
71 }
72
73 /**
74 * ib_umem_get - Pin and DMA map userspace memory.
75 *
76 * If access flags indicate ODP memory, avoid pinning. Instead, stores
77 * the mm for future page fault handling in conjunction with MMU notifiers.
78 *
79 * @context: userspace context to pin memory for
80 * @addr: userspace virtual address to start at
81 * @size: length of region to pin
82 * @access: IB_ACCESS_xxx flags for memory being pinned
83 * @dmasync: flush in-flight DMA when the memory region is written
84 */
ib_umem_get(struct ib_ucontext * context,unsigned long addr,size_t size,int access,int dmasync)85 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
86 size_t size, int access, int dmasync)
87 {
88 struct ib_umem *umem;
89 struct page **page_list;
90 struct vm_area_struct **vma_list;
91 unsigned long locked;
92 unsigned long cur_base;
93 unsigned long npages;
94 int ret;
95 int i;
96 struct dma_attrs dma_attrs = { 0 };
97 struct scatterlist *sg, *sg_list_start;
98 int need_release = 0;
99 unsigned int gup_flags = FOLL_WRITE;
100
101 if (dmasync)
102 dma_attrs.flags |= DMA_ATTR_WRITE_BARRIER;
103
104 if (!size)
105 return ERR_PTR(-EINVAL);
106
107 /*
108 * If the combination of the addr and size requested for this memory
109 * region causes an integer overflow, return error.
110 */
111 if (((addr + size) < addr) ||
112 PAGE_ALIGN(addr + size) < (addr + size))
113 return ERR_PTR(-EINVAL);
114
115 if (priv_check(curthread, PRIV_VM_MLOCK) != 0)
116 return ERR_PTR(-EPERM);
117
118 umem = kzalloc(sizeof *umem, GFP_KERNEL);
119 if (!umem)
120 return ERR_PTR(-ENOMEM);
121
122 umem->context = context;
123 umem->length = size;
124 umem->address = addr;
125 umem->page_size = PAGE_SIZE;
126 umem->pid = get_pid(task_pid(current));
127 /*
128 * We ask for writable memory if any of the following
129 * access flags are set. "Local write" and "remote write"
130 * obviously require write access. "Remote atomic" can do
131 * things like fetch and add, which will modify memory, and
132 * "MW bind" can change permissions by binding a window.
133 */
134 umem->writable = !!(access &
135 (IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE |
136 IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
137
138 if (access & IB_ACCESS_ON_DEMAND) {
139 ret = ib_umem_odp_get(context, umem);
140 if (ret) {
141 kfree(umem);
142 return ERR_PTR(ret);
143 }
144 return umem;
145 }
146
147 umem->odp_data = NULL;
148
149 page_list = (struct page **) __get_free_page(GFP_KERNEL);
150 if (!page_list) {
151 kfree(umem);
152 return ERR_PTR(-ENOMEM);
153 }
154
155 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
156
157 npages = ib_umem_num_pages(umem);
158
159 down_write(¤t->mm->mmap_sem);
160
161 locked = npages + current->mm->pinned_vm;
162
163 cur_base = addr & PAGE_MASK;
164
165 if (npages == 0 || npages > UINT_MAX) {
166 ret = -EINVAL;
167 goto out;
168 }
169
170 ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
171 if (ret)
172 goto out;
173
174 if (!umem->writable)
175 gup_flags |= FOLL_FORCE;
176
177 need_release = 1;
178 sg_list_start = umem->sg_head.sgl;
179
180 while (npages) {
181 ret = get_user_pages(cur_base,
182 min_t(unsigned long, npages,
183 PAGE_SIZE / sizeof (struct page *)),
184 gup_flags, page_list, vma_list);
185
186 if (ret < 0)
187 goto out;
188
189 umem->npages += ret;
190 cur_base += ret * PAGE_SIZE;
191 npages -= ret;
192
193 for_each_sg(sg_list_start, sg, ret, i) {
194 sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
195 }
196
197 /* preparing for next loop */
198 sg_list_start = sg;
199 }
200
201 umem->nmap = ib_dma_map_sg_attrs(context->device,
202 umem->sg_head.sgl,
203 umem->npages,
204 DMA_BIDIRECTIONAL,
205 &dma_attrs);
206
207 if (umem->nmap <= 0) {
208 ret = -ENOMEM;
209 goto out;
210 }
211
212 ret = 0;
213
214 out:
215 if (ret < 0) {
216 if (need_release)
217 __ib_umem_release(context->device, umem, 0);
218 put_pid(umem->pid);
219 kfree(umem);
220 } else
221 current->mm->pinned_vm = locked;
222
223 up_write(¤t->mm->mmap_sem);
224 if (vma_list)
225 free_page((unsigned long) vma_list);
226 free_page((unsigned long) page_list);
227
228 return ret < 0 ? ERR_PTR(ret) : umem;
229 }
230 EXPORT_SYMBOL(ib_umem_get);
231
ib_umem_account(struct work_struct * work)232 static void ib_umem_account(struct work_struct *work)
233 {
234 struct ib_umem *umem = container_of(work, struct ib_umem, work);
235
236 down_write(&umem->mm->mmap_sem);
237 umem->mm->pinned_vm -= umem->diff;
238 up_write(&umem->mm->mmap_sem);
239 mmput(umem->mm);
240 kfree(umem);
241 }
242
243 /**
244 * ib_umem_release - release memory pinned with ib_umem_get
245 * @umem: umem struct to release
246 */
ib_umem_release(struct ib_umem * umem)247 void ib_umem_release(struct ib_umem *umem)
248 {
249 struct mm_struct *mm;
250 struct task_struct *task;
251 unsigned long diff;
252
253 if (!umem)
254 return;
255
256 if (umem->odp_data) {
257 ib_umem_odp_release(umem);
258 return;
259 }
260
261 __ib_umem_release(umem->context->device, umem, 1);
262
263 task = get_pid_task(umem->pid, PIDTYPE_PID);
264 put_pid(umem->pid);
265 if (!task)
266 goto out;
267 mm = get_task_mm(task);
268 put_task_struct(task);
269 if (!mm)
270 goto out;
271
272 diff = ib_umem_num_pages(umem);
273
274 /*
275 * We may be called with the mm's mmap_sem already held. This
276 * can happen when a userspace munmap() is the call that drops
277 * the last reference to our file and calls our release
278 * method. If there are memory regions to destroy, we'll end
279 * up here and not be able to take the mmap_sem. In that case
280 * we defer the vm_locked accounting to the system workqueue.
281 */
282 if (umem->context->closing) {
283 if (!down_write_trylock(&mm->mmap_sem)) {
284 INIT_WORK(&umem->work, ib_umem_account);
285 umem->mm = mm;
286 umem->diff = diff;
287
288 queue_work(ib_wq, &umem->work);
289 return;
290 }
291 } else
292 down_write(&mm->mmap_sem);
293
294 mm->pinned_vm -= diff;
295 up_write(&mm->mmap_sem);
296 mmput(mm);
297 out:
298 kfree(umem);
299 }
300 EXPORT_SYMBOL(ib_umem_release);
301
ib_umem_page_count(struct ib_umem * umem)302 int ib_umem_page_count(struct ib_umem *umem)
303 {
304 int shift;
305 int i;
306 int n;
307 struct scatterlist *sg;
308
309 if (umem->odp_data)
310 return ib_umem_num_pages(umem);
311
312 shift = ilog2(umem->page_size);
313
314 n = 0;
315 for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
316 n += sg_dma_len(sg) >> shift;
317
318 return n;
319 }
320 EXPORT_SYMBOL(ib_umem_page_count);
321
322 /*
323 * Copy from the given ib_umem's pages to the given buffer.
324 *
325 * umem - the umem to copy from
326 * offset - offset to start copying from
327 * dst - destination buffer
328 * length - buffer length
329 *
330 * Returns 0 on success, or an error code.
331 */
ib_umem_copy_from(void * dst,struct ib_umem * umem,size_t offset,size_t length)332 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
333 size_t length)
334 {
335 size_t end = offset + length;
336 int ret;
337
338 if (offset > umem->length || length > umem->length - offset) {
339 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n",
340 offset, umem->length, end);
341 return -EINVAL;
342 }
343
344 #ifdef __linux__
345 ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length,
346 offset + ib_umem_offset(umem));
347 #else
348 ret = 0;
349 #endif
350 if (ret < 0)
351 return ret;
352 else if (ret != length)
353 return -EINVAL;
354 else
355 return 0;
356 }
357 EXPORT_SYMBOL(ib_umem_copy_from);
358