1 /*
2 * Copyright (c) 2005 Topspin Communications. All rights reserved.
3 * Copyright (c) 2005 Cisco Systems. All rights reserved.
4 * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
5 *
6 * This software is available to you under a choice of one of two
7 * licenses. You may choose to be licensed under the terms of the GNU
8 * General Public License (GPL) Version 2, available from the file
9 * COPYING in the main directory of this source tree, or the
10 * OpenIB.org BSD license below:
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above
17 * copyright notice, this list of conditions and the following
18 * disclaimer.
19 *
20 * - Redistributions in binary form must reproduce the above
21 * copyright notice, this list of conditions and the following
22 * disclaimer in the documentation and/or other materials
23 * provided with the distribution.
24 *
25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
29 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
30 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
31 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32 * SOFTWARE.
33 */
34
35 #include <linux/mm.h>
36 #include <linux/dma-mapping.h>
37 #include <linux/sched.h>
38 #include <linux/export.h>
39 #include <linux/hugetlb.h>
40 #include <linux/dma-attrs.h>
41 #include <linux/slab.h>
42 #include <rdma/ib_umem_odp.h>
43
44 #include "uverbs.h"
45
46
__ib_umem_release(struct ib_device * dev,struct ib_umem * umem,int dirty)47 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
48 {
49 struct scatterlist *sg;
50 struct page *page;
51 int i;
52
53 if (umem->nmap > 0)
54 ib_dma_unmap_sg(dev, umem->sg_head.sgl,
55 umem->nmap,
56 DMA_BIDIRECTIONAL);
57
58 for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
59
60 page = sg_page(sg);
61 if (umem->writable && dirty)
62 set_page_dirty_lock(page);
63 put_page(page);
64 }
65
66 sg_free_table(&umem->sg_head);
67 return;
68
69 }
70
71 /**
72 * ib_umem_get - Pin and DMA map userspace memory.
73 *
74 * If access flags indicate ODP memory, avoid pinning. Instead, stores
75 * the mm for future page fault handling in conjunction with MMU notifiers.
76 *
77 * @context: userspace context to pin memory for
78 * @addr: userspace virtual address to start at
79 * @size: length of region to pin
80 * @access: IB_ACCESS_xxx flags for memory being pinned
81 * @dmasync: flush in-flight DMA when the memory region is written
82 */
ib_umem_get(struct ib_ucontext * context,unsigned long addr,size_t size,int access,int dmasync)83 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
84 size_t size, int access, int dmasync)
85 {
86 struct ib_umem *umem;
87 struct page **page_list;
88 struct vm_area_struct **vma_list;
89 unsigned long locked;
90 unsigned long lock_limit;
91 unsigned long cur_base;
92 unsigned long npages;
93 int ret;
94 int i;
95 DEFINE_DMA_ATTRS(attrs);
96 struct scatterlist *sg, *sg_list_start;
97 int need_release = 0;
98 unsigned int gup_flags = FOLL_WRITE;
99
100 if (dmasync)
101 dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
102
103 if (!size)
104 return ERR_PTR(-EINVAL);
105
106 /*
107 * If the combination of the addr and size requested for this memory
108 * region causes an integer overflow, return error.
109 */
110 if (((addr + size) < addr) ||
111 PAGE_ALIGN(addr + size) < (addr + size))
112 return ERR_PTR(-EINVAL);
113
114 if (!can_do_mlock())
115 return ERR_PTR(-EPERM);
116
117 umem = kzalloc(sizeof *umem, GFP_KERNEL);
118 if (!umem)
119 return ERR_PTR(-ENOMEM);
120
121 umem->context = context;
122 umem->length = size;
123 umem->address = addr;
124 umem->page_size = PAGE_SIZE;
125 umem->pid = get_task_pid(current, PIDTYPE_PID);
126 umem->writable = ib_access_writable(access);
127
128 if (access & IB_ACCESS_ON_DEMAND) {
129 put_pid(umem->pid);
130 ret = ib_umem_odp_get(context, umem);
131 if (ret) {
132 kfree(umem);
133 return ERR_PTR(ret);
134 }
135 return umem;
136 }
137
138 umem->odp_data = NULL;
139
140 /* We assume the memory is from hugetlb until proved otherwise */
141 umem->hugetlb = 1;
142
143 page_list = (struct page **) __get_free_page(GFP_KERNEL);
144 if (!page_list) {
145 put_pid(umem->pid);
146 kfree(umem);
147 return ERR_PTR(-ENOMEM);
148 }
149
150 /*
151 * if we can't alloc the vma_list, it's not so bad;
152 * just assume the memory is not hugetlb memory
153 */
154 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
155 if (!vma_list)
156 umem->hugetlb = 0;
157
158 npages = ib_umem_num_pages(umem);
159
160 down_write(¤t->mm->mmap_sem);
161
162 locked = npages + current->mm->pinned_vm;
163 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
164
165 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
166 ret = -ENOMEM;
167 goto out;
168 }
169
170 cur_base = addr & PAGE_MASK;
171
172 if (npages == 0 || npages > UINT_MAX) {
173 ret = -EINVAL;
174 goto out;
175 }
176
177 ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
178 if (ret)
179 goto out;
180
181 if (!umem->writable)
182 gup_flags |= FOLL_FORCE;
183
184 need_release = 1;
185 sg_list_start = umem->sg_head.sgl;
186
187 while (npages) {
188 ret = get_user_pages(current, current->mm, cur_base,
189 min_t(unsigned long, npages,
190 PAGE_SIZE / sizeof (struct page *)),
191 gup_flags, page_list, vma_list);
192
193 if (ret < 0)
194 goto out;
195
196 umem->npages += ret;
197 cur_base += ret * PAGE_SIZE;
198 npages -= ret;
199
200 for_each_sg(sg_list_start, sg, ret, i) {
201 if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
202 umem->hugetlb = 0;
203
204 sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
205 }
206
207 /* preparing for next loop */
208 sg_list_start = sg;
209 }
210
211 umem->nmap = ib_dma_map_sg_attrs(context->device,
212 umem->sg_head.sgl,
213 umem->npages,
214 DMA_BIDIRECTIONAL,
215 &attrs);
216
217 if (umem->nmap <= 0) {
218 ret = -ENOMEM;
219 goto out;
220 }
221
222 ret = 0;
223
224 out:
225 if (ret < 0) {
226 if (need_release)
227 __ib_umem_release(context->device, umem, 0);
228 put_pid(umem->pid);
229 kfree(umem);
230 } else
231 current->mm->pinned_vm = locked;
232
233 up_write(¤t->mm->mmap_sem);
234 if (vma_list)
235 free_page((unsigned long) vma_list);
236 free_page((unsigned long) page_list);
237
238 return ret < 0 ? ERR_PTR(ret) : umem;
239 }
240 EXPORT_SYMBOL(ib_umem_get);
241
ib_umem_account(struct work_struct * work)242 static void ib_umem_account(struct work_struct *work)
243 {
244 struct ib_umem *umem = container_of(work, struct ib_umem, work);
245
246 down_write(&umem->mm->mmap_sem);
247 umem->mm->pinned_vm -= umem->diff;
248 up_write(&umem->mm->mmap_sem);
249 mmput(umem->mm);
250 kfree(umem);
251 }
252
253 /**
254 * ib_umem_release - release memory pinned with ib_umem_get
255 * @umem: umem struct to release
256 */
ib_umem_release(struct ib_umem * umem)257 void ib_umem_release(struct ib_umem *umem)
258 {
259 struct ib_ucontext *context = umem->context;
260 struct mm_struct *mm;
261 struct task_struct *task;
262 unsigned long diff;
263
264 if (umem->odp_data) {
265 ib_umem_odp_release(umem);
266 return;
267 }
268
269 __ib_umem_release(umem->context->device, umem, 1);
270
271 task = get_pid_task(umem->pid, PIDTYPE_PID);
272 put_pid(umem->pid);
273 if (!task)
274 goto out;
275 mm = get_task_mm(task);
276 put_task_struct(task);
277 if (!mm)
278 goto out;
279
280 diff = ib_umem_num_pages(umem);
281
282 /*
283 * We may be called with the mm's mmap_sem already held. This
284 * can happen when a userspace munmap() is the call that drops
285 * the last reference to our file and calls our release
286 * method. If there are memory regions to destroy, we'll end
287 * up here and not be able to take the mmap_sem. In that case
288 * we defer the vm_locked accounting to the system workqueue.
289 */
290 if (context->closing) {
291 if (!down_write_trylock(&mm->mmap_sem)) {
292 INIT_WORK(&umem->work, ib_umem_account);
293 umem->mm = mm;
294 umem->diff = diff;
295
296 queue_work(ib_wq, &umem->work);
297 return;
298 }
299 } else
300 down_write(&mm->mmap_sem);
301
302 mm->pinned_vm -= diff;
303 up_write(&mm->mmap_sem);
304 mmput(mm);
305 out:
306 kfree(umem);
307 }
308 EXPORT_SYMBOL(ib_umem_release);
309
ib_umem_page_count(struct ib_umem * umem)310 int ib_umem_page_count(struct ib_umem *umem)
311 {
312 int shift;
313 int i;
314 int n;
315 struct scatterlist *sg;
316
317 if (umem->odp_data)
318 return ib_umem_num_pages(umem);
319
320 shift = ilog2(umem->page_size);
321
322 n = 0;
323 for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
324 n += sg_dma_len(sg) >> shift;
325
326 return n;
327 }
328 EXPORT_SYMBOL(ib_umem_page_count);
329
330 /*
331 * Copy from the given ib_umem's pages to the given buffer.
332 *
333 * umem - the umem to copy from
334 * offset - offset to start copying from
335 * dst - destination buffer
336 * length - buffer length
337 *
338 * Returns 0 on success, or an error code.
339 */
ib_umem_copy_from(void * dst,struct ib_umem * umem,size_t offset,size_t length)340 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
341 size_t length)
342 {
343 size_t end = offset + length;
344 int ret;
345
346 if (offset > umem->length || length > umem->length - offset) {
347 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n",
348 offset, umem->length, end);
349 return -EINVAL;
350 }
351
352 ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->npages, dst, length,
353 offset + ib_umem_offset(umem));
354
355 if (ret < 0)
356 return ret;
357 else if (ret != length)
358 return -EINVAL;
359 else
360 return 0;
361 }
362 EXPORT_SYMBOL(ib_umem_copy_from);
363