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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
43#include "uverbs.h"
44
45#define IB_UMEM_MAX_PAGE_CHUNK \
46 ((PAGE_SIZE - offsetof(struct ib_umem_chunk, page_list)) / \
47 ((void *) &((struct ib_umem_chunk *) 0)->page_list[1] - \
48 (void *) &((struct ib_umem_chunk *) 0)->page_list[0]))
49
50static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
51{
52 struct ib_umem_chunk *chunk, *tmp;
53 int i;
54
55 list_for_each_entry_safe(chunk, tmp, &umem->chunk_list, list) {
56 ib_dma_unmap_sg(dev, chunk->page_list,
57 chunk->nents, DMA_BIDIRECTIONAL);
58 for (i = 0; i < chunk->nents; ++i) {
59 struct page *page = sg_page(&chunk->page_list[i]);
60
61 if (umem->writable && dirty)
62 set_page_dirty_lock(page);
63 put_page(page);
64 }
65
66 kfree(chunk);
67 }
68}
69
70/**
71 * ib_umem_get - Pin and DMA map userspace memory.
72 * @context: userspace context to pin memory for
73 * @addr: userspace virtual address to start at
74 * @size: length of region to pin
75 * @access: IB_ACCESS_xxx flags for memory being pinned
76 * @dmasync: flush in-flight DMA when the memory region is written
77 */
78struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
79 size_t size, int access, int dmasync)
80{
81 struct ib_umem *umem;
82 struct page **page_list;
83 struct vm_area_struct **vma_list;
84 struct ib_umem_chunk *chunk;
85 unsigned long locked;
86 unsigned long lock_limit;
87 unsigned long cur_base;
88 unsigned long npages;
89 int ret;
90 int off;
91 int i;
92 DEFINE_DMA_ATTRS(attrs);
93
94 if (dmasync)
95 dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
96
97 if (!can_do_mlock())
98 return ERR_PTR(-EPERM);
99
100 umem = kmalloc(sizeof *umem, GFP_KERNEL);
101 if (!umem)
102 return ERR_PTR(-ENOMEM);
103
104 umem->context = context;
105 umem->length = size;
106 umem->offset = addr & ~PAGE_MASK;
107 umem->page_size = PAGE_SIZE;
108 /*
109 * We ask for writable memory if any access flags other than
110 * "remote read" are set. "Local write" and "remote write"
111 * obviously require write access. "Remote atomic" can do
112 * things like fetch and add, which will modify memory, and
113 * "MW bind" can change permissions by binding a window.
114 */
115 umem->writable = !!(access & ~IB_ACCESS_REMOTE_READ);
116
117 /* We assume the memory is from hugetlb until proved otherwise */
118 umem->hugetlb = 1;
119
120 INIT_LIST_HEAD(&umem->chunk_list);
121
122 page_list = (struct page **) __get_free_page(GFP_KERNEL);
123 if (!page_list) {
124 kfree(umem);
125 return ERR_PTR(-ENOMEM);
126 }
127
128 /*
129 * if we can't alloc the vma_list, it's not so bad;
130 * just assume the memory is not hugetlb memory
131 */
132 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
133 if (!vma_list)
134 umem->hugetlb = 0;
135
136 npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT;
137
138 down_write(¤t->mm->mmap_sem);
139
140 locked = npages + current->mm->pinned_vm;
141 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
142
143 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
144 ret = -ENOMEM;
145 goto out;
146 }
147
148 cur_base = addr & PAGE_MASK;
149
150 ret = 0;
151 while (npages) {
152 ret = get_user_pages(current, current->mm, cur_base,
153 min_t(unsigned long, npages,
154 PAGE_SIZE / sizeof (struct page *)),
155 1, !umem->writable, page_list, vma_list);
156
157 if (ret < 0)
158 goto out;
159
160 cur_base += ret * PAGE_SIZE;
161 npages -= ret;
162
163 off = 0;
164
165 while (ret) {
166 chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) *
167 min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK),
168 GFP_KERNEL);
169 if (!chunk) {
170 ret = -ENOMEM;
171 goto out;
172 }
173
174 chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK);
175 sg_init_table(chunk->page_list, chunk->nents);
176 for (i = 0; i < chunk->nents; ++i) {
177 if (vma_list &&
178 !is_vm_hugetlb_page(vma_list[i + off]))
179 umem->hugetlb = 0;
180 sg_set_page(&chunk->page_list[i], page_list[i + off], PAGE_SIZE, 0);
181 }
182
183 chunk->nmap = ib_dma_map_sg_attrs(context->device,
184 &chunk->page_list[0],
185 chunk->nents,
186 DMA_BIDIRECTIONAL,
187 &attrs);
188 if (chunk->nmap <= 0) {
189 for (i = 0; i < chunk->nents; ++i)
190 put_page(sg_page(&chunk->page_list[i]));
191 kfree(chunk);
192
193 ret = -ENOMEM;
194 goto out;
195 }
196
197 ret -= chunk->nents;
198 off += chunk->nents;
199 list_add_tail(&chunk->list, &umem->chunk_list);
200 }
201
202 ret = 0;
203 }
204
205out:
206 if (ret < 0) {
207 __ib_umem_release(context->device, umem, 0);
208 kfree(umem);
209 } else
210 current->mm->pinned_vm = locked;
211
212 up_write(¤t->mm->mmap_sem);
213 if (vma_list)
214 free_page((unsigned long) vma_list);
215 free_page((unsigned long) page_list);
216
217 return ret < 0 ? ERR_PTR(ret) : umem;
218}
219EXPORT_SYMBOL(ib_umem_get);
220
221static void ib_umem_account(struct work_struct *work)
222{
223 struct ib_umem *umem = container_of(work, struct ib_umem, work);
224
225 down_write(&umem->mm->mmap_sem);
226 umem->mm->pinned_vm -= umem->diff;
227 up_write(&umem->mm->mmap_sem);
228 mmput(umem->mm);
229 kfree(umem);
230}
231
232/**
233 * ib_umem_release - release memory pinned with ib_umem_get
234 * @umem: umem struct to release
235 */
236void ib_umem_release(struct ib_umem *umem)
237{
238 struct ib_ucontext *context = umem->context;
239 struct mm_struct *mm;
240 unsigned long diff;
241
242 __ib_umem_release(umem->context->device, umem, 1);
243
244 mm = get_task_mm(current);
245 if (!mm) {
246 kfree(umem);
247 return;
248 }
249
250 diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
251
252 /*
253 * We may be called with the mm's mmap_sem already held. This
254 * can happen when a userspace munmap() is the call that drops
255 * the last reference to our file and calls our release
256 * method. If there are memory regions to destroy, we'll end
257 * up here and not be able to take the mmap_sem. In that case
258 * we defer the vm_locked accounting to the system workqueue.
259 */
260 if (context->closing) {
261 if (!down_write_trylock(&mm->mmap_sem)) {
262 INIT_WORK(&umem->work, ib_umem_account);
263 umem->mm = mm;
264 umem->diff = diff;
265
266 queue_work(ib_wq, &umem->work);
267 return;
268 }
269 } else
270 down_write(&mm->mmap_sem);
271
272 current->mm->pinned_vm -= diff;
273 up_write(&mm->mmap_sem);
274 mmput(mm);
275 kfree(umem);
276}
277EXPORT_SYMBOL(ib_umem_release);
278
279int ib_umem_page_count(struct ib_umem *umem)
280{
281 struct ib_umem_chunk *chunk;
282 int shift;
283 int i;
284 int n;
285
286 shift = ilog2(umem->page_size);
287
288 n = 0;
289 list_for_each_entry(chunk, &umem->chunk_list, list)
290 for (i = 0; i < chunk->nmap; ++i)
291 n += sg_dma_len(&chunk->page_list[i]) >> shift;
292
293 return n;
294}
295EXPORT_SYMBOL(ib_umem_page_count);