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/signal.h>
38 #include <linux/sched/mm.h>
39 #include <linux/export.h>
40 #include <linux/slab.h>
41 #include <linux/pagemap.h>
42 #include <rdma/ib_umem_odp.h>
43
44 #include "uverbs.h"
45
__ib_umem_release(struct ib_device * dev,struct ib_umem * umem,int dirty)46 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
47 {
48 struct sg_page_iter sg_iter;
49 struct page *page;
50
51 if (umem->nmap > 0)
52 ib_dma_unmap_sg(dev, umem->sg_head.sgl, umem->sg_nents,
53 DMA_BIDIRECTIONAL);
54
55 for_each_sg_page(umem->sg_head.sgl, &sg_iter, umem->sg_nents, 0) {
56 page = sg_page_iter_page(&sg_iter);
57 put_user_pages_dirty_lock(&page, 1, umem->writable && dirty);
58 }
59
60 sg_free_table(&umem->sg_head);
61 }
62
63 /* ib_umem_add_sg_table - Add N contiguous pages to scatter table
64 *
65 * sg: current scatterlist entry
66 * page_list: array of npage struct page pointers
67 * npages: number of pages in page_list
68 * max_seg_sz: maximum segment size in bytes
69 * nents: [out] number of entries in the scatterlist
70 *
71 * Return new end of scatterlist
72 */
ib_umem_add_sg_table(struct scatterlist * sg,struct page ** page_list,unsigned long npages,unsigned int max_seg_sz,int * nents)73 static struct scatterlist *ib_umem_add_sg_table(struct scatterlist *sg,
74 struct page **page_list,
75 unsigned long npages,
76 unsigned int max_seg_sz,
77 int *nents)
78 {
79 unsigned long first_pfn;
80 unsigned long i = 0;
81 bool update_cur_sg = false;
82 bool first = !sg_page(sg);
83
84 /* Check if new page_list is contiguous with end of previous page_list.
85 * sg->length here is a multiple of PAGE_SIZE and sg->offset is 0.
86 */
87 if (!first && (page_to_pfn(sg_page(sg)) + (sg->length >> PAGE_SHIFT) ==
88 page_to_pfn(page_list[0])))
89 update_cur_sg = true;
90
91 while (i != npages) {
92 unsigned long len;
93 struct page *first_page = page_list[i];
94
95 first_pfn = page_to_pfn(first_page);
96
97 /* Compute the number of contiguous pages we have starting
98 * at i
99 */
100 for (len = 0; i != npages &&
101 first_pfn + len == page_to_pfn(page_list[i]) &&
102 len < (max_seg_sz >> PAGE_SHIFT);
103 len++)
104 i++;
105
106 /* Squash N contiguous pages from page_list into current sge */
107 if (update_cur_sg) {
108 if ((max_seg_sz - sg->length) >= (len << PAGE_SHIFT)) {
109 sg_set_page(sg, sg_page(sg),
110 sg->length + (len << PAGE_SHIFT),
111 0);
112 update_cur_sg = false;
113 continue;
114 }
115 update_cur_sg = false;
116 }
117
118 /* Squash N contiguous pages into next sge or first sge */
119 if (!first)
120 sg = sg_next(sg);
121
122 (*nents)++;
123 sg_set_page(sg, first_page, len << PAGE_SHIFT, 0);
124 first = false;
125 }
126
127 return sg;
128 }
129
130 /**
131 * ib_umem_find_best_pgsz - Find best HW page size to use for this MR
132 *
133 * @umem: umem struct
134 * @pgsz_bitmap: bitmap of HW supported page sizes
135 * @virt: IOVA
136 *
137 * This helper is intended for HW that support multiple page
138 * sizes but can do only a single page size in an MR.
139 *
140 * Returns 0 if the umem requires page sizes not supported by
141 * the driver to be mapped. Drivers always supporting PAGE_SIZE
142 * or smaller will never see a 0 result.
143 */
ib_umem_find_best_pgsz(struct ib_umem * umem,unsigned long pgsz_bitmap,unsigned long virt)144 unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
145 unsigned long pgsz_bitmap,
146 unsigned long virt)
147 {
148 struct scatterlist *sg;
149 unsigned int best_pg_bit;
150 unsigned long va, pgoff;
151 dma_addr_t mask;
152 int i;
153
154 /* At minimum, drivers must support PAGE_SIZE or smaller */
155 if (WARN_ON(!(pgsz_bitmap & GENMASK(PAGE_SHIFT, 0))))
156 return 0;
157
158 va = virt;
159 /* max page size not to exceed MR length */
160 mask = roundup_pow_of_two(umem->length);
161 /* offset into first SGL */
162 pgoff = umem->address & ~PAGE_MASK;
163
164 for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i) {
165 /* Walk SGL and reduce max page size if VA/PA bits differ
166 * for any address.
167 */
168 mask |= (sg_dma_address(sg) + pgoff) ^ va;
169 if (i && i != (umem->nmap - 1))
170 /* restrict by length as well for interior SGEs */
171 mask |= sg_dma_len(sg);
172 va += sg_dma_len(sg) - pgoff;
173 pgoff = 0;
174 }
175 best_pg_bit = rdma_find_pg_bit(mask, pgsz_bitmap);
176
177 return BIT_ULL(best_pg_bit);
178 }
179 EXPORT_SYMBOL(ib_umem_find_best_pgsz);
180
181 /**
182 * ib_umem_get - Pin and DMA map userspace memory.
183 *
184 * @udata: userspace context to pin memory for
185 * @addr: userspace virtual address to start at
186 * @size: length of region to pin
187 * @access: IB_ACCESS_xxx flags for memory being pinned
188 * @dmasync: flush in-flight DMA when the memory region is written
189 */
ib_umem_get(struct ib_udata * udata,unsigned long addr,size_t size,int access,int dmasync)190 struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr,
191 size_t size, int access, int dmasync)
192 {
193 struct ib_ucontext *context;
194 struct ib_umem *umem;
195 struct page **page_list;
196 unsigned long lock_limit;
197 unsigned long new_pinned;
198 unsigned long cur_base;
199 struct mm_struct *mm;
200 unsigned long npages;
201 int ret;
202 unsigned long dma_attrs = 0;
203 struct scatterlist *sg;
204 unsigned int gup_flags = FOLL_WRITE;
205
206 if (!udata)
207 return ERR_PTR(-EIO);
208
209 context = container_of(udata, struct uverbs_attr_bundle, driver_udata)
210 ->context;
211 if (!context)
212 return ERR_PTR(-EIO);
213
214 if (dmasync)
215 dma_attrs |= DMA_ATTR_WRITE_BARRIER;
216
217 /*
218 * If the combination of the addr and size requested for this memory
219 * region causes an integer overflow, return error.
220 */
221 if (((addr + size) < addr) ||
222 PAGE_ALIGN(addr + size) < (addr + size))
223 return ERR_PTR(-EINVAL);
224
225 if (!can_do_mlock())
226 return ERR_PTR(-EPERM);
227
228 if (access & IB_ACCESS_ON_DEMAND)
229 return ERR_PTR(-EOPNOTSUPP);
230
231 umem = kzalloc(sizeof(*umem), GFP_KERNEL);
232 if (!umem)
233 return ERR_PTR(-ENOMEM);
234 umem->ibdev = context->device;
235 umem->length = size;
236 umem->address = addr;
237 umem->writable = ib_access_writable(access);
238 umem->owning_mm = mm = current->mm;
239 mmgrab(mm);
240
241 page_list = (struct page **) __get_free_page(GFP_KERNEL);
242 if (!page_list) {
243 ret = -ENOMEM;
244 goto umem_kfree;
245 }
246
247 npages = ib_umem_num_pages(umem);
248 if (npages == 0 || npages > UINT_MAX) {
249 ret = -EINVAL;
250 goto out;
251 }
252
253 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
254
255 new_pinned = atomic64_add_return(npages, &mm->pinned_vm);
256 if (new_pinned > lock_limit && !capable(CAP_IPC_LOCK)) {
257 atomic64_sub(npages, &mm->pinned_vm);
258 ret = -ENOMEM;
259 goto out;
260 }
261
262 cur_base = addr & PAGE_MASK;
263
264 ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
265 if (ret)
266 goto vma;
267
268 if (!umem->writable)
269 gup_flags |= FOLL_FORCE;
270
271 sg = umem->sg_head.sgl;
272
273 while (npages) {
274 down_read(&mm->mmap_sem);
275 ret = get_user_pages(cur_base,
276 min_t(unsigned long, npages,
277 PAGE_SIZE / sizeof (struct page *)),
278 gup_flags | FOLL_LONGTERM,
279 page_list, NULL);
280 if (ret < 0) {
281 up_read(&mm->mmap_sem);
282 goto umem_release;
283 }
284
285 cur_base += ret * PAGE_SIZE;
286 npages -= ret;
287
288 sg = ib_umem_add_sg_table(sg, page_list, ret,
289 dma_get_max_seg_size(context->device->dma_device),
290 &umem->sg_nents);
291
292 up_read(&mm->mmap_sem);
293 }
294
295 sg_mark_end(sg);
296
297 umem->nmap = ib_dma_map_sg_attrs(context->device,
298 umem->sg_head.sgl,
299 umem->sg_nents,
300 DMA_BIDIRECTIONAL,
301 dma_attrs);
302
303 if (!umem->nmap) {
304 ret = -ENOMEM;
305 goto umem_release;
306 }
307
308 ret = 0;
309 goto out;
310
311 umem_release:
312 __ib_umem_release(context->device, umem, 0);
313 vma:
314 atomic64_sub(ib_umem_num_pages(umem), &mm->pinned_vm);
315 out:
316 free_page((unsigned long) page_list);
317 umem_kfree:
318 if (ret) {
319 mmdrop(umem->owning_mm);
320 kfree(umem);
321 }
322 return ret ? ERR_PTR(ret) : umem;
323 }
324 EXPORT_SYMBOL(ib_umem_get);
325
326 /**
327 * ib_umem_release - release memory pinned with ib_umem_get
328 * @umem: umem struct to release
329 */
ib_umem_release(struct ib_umem * umem)330 void ib_umem_release(struct ib_umem *umem)
331 {
332 if (!umem)
333 return;
334 if (umem->is_odp)
335 return ib_umem_odp_release(to_ib_umem_odp(umem));
336
337 __ib_umem_release(umem->ibdev, umem, 1);
338
339 atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm);
340 mmdrop(umem->owning_mm);
341 kfree(umem);
342 }
343 EXPORT_SYMBOL(ib_umem_release);
344
ib_umem_page_count(struct ib_umem * umem)345 int ib_umem_page_count(struct ib_umem *umem)
346 {
347 int i, n = 0;
348 struct scatterlist *sg;
349
350 for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
351 n += sg_dma_len(sg) >> PAGE_SHIFT;
352
353 return n;
354 }
355 EXPORT_SYMBOL(ib_umem_page_count);
356
357 /*
358 * Copy from the given ib_umem's pages to the given buffer.
359 *
360 * umem - the umem to copy from
361 * offset - offset to start copying from
362 * dst - destination buffer
363 * length - buffer length
364 *
365 * Returns 0 on success, or an error code.
366 */
ib_umem_copy_from(void * dst,struct ib_umem * umem,size_t offset,size_t length)367 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
368 size_t length)
369 {
370 size_t end = offset + length;
371 int ret;
372
373 if (offset > umem->length || length > umem->length - offset) {
374 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n",
375 offset, umem->length, end);
376 return -EINVAL;
377 }
378
379 ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->sg_nents, dst, length,
380 offset + ib_umem_offset(umem));
381
382 if (ret < 0)
383 return ret;
384 else if (ret != length)
385 return -EINVAL;
386 else
387 return 0;
388 }
389 EXPORT_SYMBOL(ib_umem_copy_from);
390