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 * $Id: uverbs_mem.c 2743 2005-06-28 22:27:59Z roland $
35 */
36
37 #include <linux/mm.h>
38 #include <linux/dma-mapping.h>
39 #include <linux/sched.h>
40 #include <linux/hugetlb.h>
41
42 #include "uverbs.h"
43
44 #define IB_UMEM_MAX_PAGE_CHUNK \
45 ((PAGE_SIZE - offsetof(struct ib_umem_chunk, page_list)) / \
46 ((void *) &((struct ib_umem_chunk *) 0)->page_list[1] - \
47 (void *) &((struct ib_umem_chunk *) 0)->page_list[0]))
48
49 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
50 {
51 struct ib_umem_chunk *chunk, *tmp;
52 int i;
53
54 list_for_each_entry_safe(chunk, tmp, &umem->chunk_list, list) {
55 ib_dma_unmap_sg(dev, chunk->page_list,
56 chunk->nents, DMA_BIDIRECTIONAL);
57 for (i = 0; i < chunk->nents; ++i) {
58 struct page *page = sg_page(&chunk->page_list[i]);
59
60 if (umem->writable && dirty)
61 set_page_dirty_lock(page);
62 put_page(page);
63 }
64
65 kfree(chunk);
66 }
67 }
68
69 /**
70 * ib_umem_get - Pin and DMA map userspace memory.
71 * @context: userspace context to pin memory for
72 * @addr: userspace virtual address to start at
73 * @size: length of region to pin
74 * @access: IB_ACCESS_xxx flags for memory being pinned
75 */
76 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
77 size_t size, int access)
78 {
79 struct ib_umem *umem;
80 struct page **page_list;
81 struct vm_area_struct **vma_list;
82 struct ib_umem_chunk *chunk;
83 unsigned long locked;
84 unsigned long lock_limit;
85 unsigned long cur_base;
86 unsigned long npages;
87 int ret;
88 int off;
89 int i;
90
91 if (!can_do_mlock())
92 return ERR_PTR(-EPERM);
93
94 umem = kmalloc(sizeof *umem, GFP_KERNEL);
95 if (!umem)
96 return ERR_PTR(-ENOMEM);
97
98 umem->context = context;
99 umem->length = size;
100 umem->offset = addr & ~PAGE_MASK;
101 umem->page_size = PAGE_SIZE;
102 /*
103 * We ask for writable memory if any access flags other than
104 * "remote read" are set. "Local write" and "remote write"
105 * obviously require write access. "Remote atomic" can do
106 * things like fetch and add, which will modify memory, and
107 * "MW bind" can change permissions by binding a window.
108 */
109 umem->writable = !!(access & ~IB_ACCESS_REMOTE_READ);
110
111 /* We assume the memory is from hugetlb until proved otherwise */
112 umem->hugetlb = 1;
113
114 INIT_LIST_HEAD(&umem->chunk_list);
115
116 page_list = (struct page **) __get_free_page(GFP_KERNEL);
117 if (!page_list) {
118 kfree(umem);
119 return ERR_PTR(-ENOMEM);
120 }
121
122 /*
123 * if we can't alloc the vma_list, it's not so bad;
124 * just assume the memory is not hugetlb memory
125 */
126 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
127 if (!vma_list)
128 umem->hugetlb = 0;
129
130 npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT;
131
132 down_write(¤t->mm->mmap_sem);
133
134 locked = npages + current->mm->locked_vm;
135 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
136
137 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
138 ret = -ENOMEM;
139 goto out;
140 }
141
142 cur_base = addr & PAGE_MASK;
143
144 ret = 0;
145 while (npages) {
146 ret = get_user_pages(current, current->mm, cur_base,
147 min_t(int, npages,
148 PAGE_SIZE / sizeof (struct page *)),
149 1, !umem->writable, page_list, vma_list);
150
151 if (ret < 0)
152 goto out;
153
154 cur_base += ret * PAGE_SIZE;
155 npages -= ret;
156
157 off = 0;
158
159 while (ret) {
160 chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) *
161 min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK),
162 GFP_KERNEL);
163 if (!chunk) {
164 ret = -ENOMEM;
165 goto out;
166 }
167
168 chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK);
169 sg_init_table(chunk->page_list, chunk->nents);
170 for (i = 0; i < chunk->nents; ++i) {
171 if (vma_list &&
172 !is_vm_hugetlb_page(vma_list[i + off]))
173 umem->hugetlb = 0;
174 sg_set_page(&chunk->page_list[i], page_list[i + off], PAGE_SIZE, 0);
175 }
176
177 chunk->nmap = ib_dma_map_sg(context->device,
178 &chunk->page_list[0],
179 chunk->nents,
180 DMA_BIDIRECTIONAL);
181 if (chunk->nmap <= 0) {
182 for (i = 0; i < chunk->nents; ++i)
183 put_page(sg_page(&chunk->page_list[i]));
184 kfree(chunk);
185
186 ret = -ENOMEM;
187 goto out;
188 }
189
190 ret -= chunk->nents;
191 off += chunk->nents;
192 list_add_tail(&chunk->list, &umem->chunk_list);
193 }
194
195 ret = 0;
196 }
197
198 out:
199 if (ret < 0) {
200 __ib_umem_release(context->device, umem, 0);
201 kfree(umem);
202 } else
203 current->mm->locked_vm = locked;
204
205 up_write(¤t->mm->mmap_sem);
206 if (vma_list)
207 free_page((unsigned long) vma_list);
208 free_page((unsigned long) page_list);
209
210 return ret < 0 ? ERR_PTR(ret) : umem;
211 }
212 EXPORT_SYMBOL(ib_umem_get);
213
214 static void ib_umem_account(struct work_struct *work)
215 {
216 struct ib_umem *umem = container_of(work, struct ib_umem, work);
217
218 down_write(&umem->mm->mmap_sem);
219 umem->mm->locked_vm -= umem->diff;
220 up_write(&umem->mm->mmap_sem);
221 mmput(umem->mm);
222 kfree(umem);
223 }
224
225 /**
226 * ib_umem_release - release memory pinned with ib_umem_get
227 * @umem: umem struct to release
228 */
229 void ib_umem_release(struct ib_umem *umem)
230 {
231 struct ib_ucontext *context = umem->context;
232 struct mm_struct *mm;
233 unsigned long diff;
234
235 __ib_umem_release(umem->context->device, umem, 1);
236
237 mm = get_task_mm(current);
238 if (!mm) {
239 kfree(umem);
240 return;
241 }
242
243 diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
244
245 /*
246 * We may be called with the mm's mmap_sem already held. This
247 * can happen when a userspace munmap() is the call that drops
248 * the last reference to our file and calls our release
249 * method. If there are memory regions to destroy, we'll end
250 * up here and not be able to take the mmap_sem. In that case
251 * we defer the vm_locked accounting to the system workqueue.
252 */
253 if (context->closing) {
254 if (!down_write_trylock(&mm->mmap_sem)) {
255 INIT_WORK(&umem->work, ib_umem_account);
256 umem->mm = mm;
257 umem->diff = diff;
258
259 schedule_work(&umem->work);
260 return;
261 }
262 } else
263 down_write(&mm->mmap_sem);
264
265 current->mm->locked_vm -= diff;
266 up_write(&mm->mmap_sem);
267 mmput(mm);
268 kfree(umem);
269 }
270 EXPORT_SYMBOL(ib_umem_release);
271
272 int ib_umem_page_count(struct ib_umem *umem)
273 {
274 struct ib_umem_chunk *chunk;
275 int shift;
276 int i;
277 int n;
278
279 shift = ilog2(umem->page_size);
280
281 n = 0;
282 list_for_each_entry(chunk, &umem->chunk_list, list)
283 for (i = 0; i < chunk->nmap; ++i)
284 n += sg_dma_len(&chunk->page_list[i]) >> shift;
285
286 return n;
287 }
288 EXPORT_SYMBOL(ib_umem_page_count);
289
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