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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 
__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 scatterlist *sg;
49 	struct page *page;
50 	int i;
51 
52 	if (umem->nmap > 0)
53 		ib_dma_unmap_sg(dev, umem->sg_head.sgl,
54 				umem->nmap,
55 				DMA_BIDIRECTIONAL);
56 
57 	for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
58 
59 		page = sg_page(sg);
60 		if (umem->writable && dirty)
61 			set_page_dirty_lock(page);
62 		put_page(page);
63 	}
64 
65 	sg_free_table(&umem->sg_head);
66 	return;
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  */
ib_umem_get(struct ib_ucontext * context,unsigned long addr,size_t size,int access,int dmasync)78 struct 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 	unsigned long locked;
85 	unsigned long lock_limit;
86 	unsigned long cur_base;
87 	unsigned long npages;
88 	int ret;
89 	int i;
90 	DEFINE_DMA_ATTRS(attrs);
91 	struct scatterlist *sg, *sg_list_start;
92 	int need_release = 0;
93 
94 	if (dmasync)
95 		dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
96 
97 	if (!size)
98 		return ERR_PTR(-EINVAL);
99 
100 	/*
101 	 * If the combination of the addr and size requested for this memory
102 	 * region causes an integer overflow, return error.
103 	 */
104 	if (((addr + size) < addr) ||
105 	    PAGE_ALIGN(addr + size) < (addr + size))
106 		return ERR_PTR(-EINVAL);
107 
108 	if (!can_do_mlock())
109 		return ERR_PTR(-EPERM);
110 
111 	umem = kzalloc(sizeof *umem, GFP_KERNEL);
112 	if (!umem)
113 		return ERR_PTR(-ENOMEM);
114 
115 	umem->context   = context;
116 	umem->length    = size;
117 	umem->offset    = addr & ~PAGE_MASK;
118 	umem->page_size = PAGE_SIZE;
119 	umem->pid       = get_task_pid(current, PIDTYPE_PID);
120 	/*
121 	 * We ask for writable memory if any access flags other than
122 	 * "remote read" are set.  "Local write" and "remote write"
123 	 * obviously require write access.  "Remote atomic" can do
124 	 * things like fetch and add, which will modify memory, and
125 	 * "MW bind" can change permissions by binding a window.
126 	 */
127 	umem->writable  = !!(access & ~IB_ACCESS_REMOTE_READ);
128 
129 	/* We assume the memory is from hugetlb until proved otherwise */
130 	umem->hugetlb   = 1;
131 
132 	page_list = (struct page **) __get_free_page(GFP_KERNEL);
133 	if (!page_list) {
134 		kfree(umem);
135 		return ERR_PTR(-ENOMEM);
136 	}
137 
138 	/*
139 	 * if we can't alloc the vma_list, it's not so bad;
140 	 * just assume the memory is not hugetlb memory
141 	 */
142 	vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
143 	if (!vma_list)
144 		umem->hugetlb = 0;
145 
146 	npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT;
147 
148 	down_write(&current->mm->mmap_sem);
149 
150 	locked     = npages + current->mm->pinned_vm;
151 	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
152 
153 	if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
154 		ret = -ENOMEM;
155 		goto out;
156 	}
157 
158 	cur_base = addr & PAGE_MASK;
159 
160 	if (npages == 0) {
161 		ret = -EINVAL;
162 		goto out;
163 	}
164 
165 	ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
166 	if (ret)
167 		goto out;
168 
169 	need_release = 1;
170 	sg_list_start = umem->sg_head.sgl;
171 
172 	while (npages) {
173 		ret = get_user_pages(current, current->mm, cur_base,
174 				     min_t(unsigned long, npages,
175 					   PAGE_SIZE / sizeof (struct page *)),
176 				     1, !umem->writable, page_list, vma_list);
177 
178 		if (ret < 0)
179 			goto out;
180 
181 		umem->npages += ret;
182 		cur_base += ret * PAGE_SIZE;
183 		npages   -= ret;
184 
185 		for_each_sg(sg_list_start, sg, ret, i) {
186 			if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
187 				umem->hugetlb = 0;
188 
189 			sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
190 		}
191 
192 		/* preparing for next loop */
193 		sg_list_start = sg;
194 	}
195 
196 	umem->nmap = ib_dma_map_sg_attrs(context->device,
197 				  umem->sg_head.sgl,
198 				  umem->npages,
199 				  DMA_BIDIRECTIONAL,
200 				  &attrs);
201 
202 	if (umem->nmap <= 0) {
203 		ret = -ENOMEM;
204 		goto out;
205 	}
206 
207 	ret = 0;
208 
209 out:
210 	if (ret < 0) {
211 		if (need_release)
212 			__ib_umem_release(context->device, umem, 0);
213 		put_pid(umem->pid);
214 		kfree(umem);
215 	} else
216 		current->mm->pinned_vm = locked;
217 
218 	up_write(&current->mm->mmap_sem);
219 	if (vma_list)
220 		free_page((unsigned long) vma_list);
221 	free_page((unsigned long) page_list);
222 
223 	return ret < 0 ? ERR_PTR(ret) : umem;
224 }
225 EXPORT_SYMBOL(ib_umem_get);
226 
ib_umem_account(struct work_struct * work)227 static void ib_umem_account(struct work_struct *work)
228 {
229 	struct ib_umem *umem = container_of(work, struct ib_umem, work);
230 
231 	down_write(&umem->mm->mmap_sem);
232 	umem->mm->pinned_vm -= umem->diff;
233 	up_write(&umem->mm->mmap_sem);
234 	mmput(umem->mm);
235 	kfree(umem);
236 }
237 
238 /**
239  * ib_umem_release - release memory pinned with ib_umem_get
240  * @umem: umem struct to release
241  */
ib_umem_release(struct ib_umem * umem)242 void ib_umem_release(struct ib_umem *umem)
243 {
244 	struct ib_ucontext *context = umem->context;
245 	struct mm_struct *mm;
246 	struct task_struct *task;
247 	unsigned long diff;
248 
249 	__ib_umem_release(umem->context->device, umem, 1);
250 
251 	task = get_pid_task(umem->pid, PIDTYPE_PID);
252 	put_pid(umem->pid);
253 	if (!task)
254 		goto out;
255 	mm = get_task_mm(task);
256 	put_task_struct(task);
257 	if (!mm)
258 		goto out;
259 
260 	diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
261 
262 	/*
263 	 * We may be called with the mm's mmap_sem already held.  This
264 	 * can happen when a userspace munmap() is the call that drops
265 	 * the last reference to our file and calls our release
266 	 * method.  If there are memory regions to destroy, we'll end
267 	 * up here and not be able to take the mmap_sem.  In that case
268 	 * we defer the vm_locked accounting to the system workqueue.
269 	 */
270 	if (context->closing) {
271 		if (!down_write_trylock(&mm->mmap_sem)) {
272 			INIT_WORK(&umem->work, ib_umem_account);
273 			umem->mm   = mm;
274 			umem->diff = diff;
275 
276 			queue_work(ib_wq, &umem->work);
277 			return;
278 		}
279 	} else
280 		down_write(&mm->mmap_sem);
281 
282 	mm->pinned_vm -= diff;
283 	up_write(&mm->mmap_sem);
284 	mmput(mm);
285 out:
286 	kfree(umem);
287 }
288 EXPORT_SYMBOL(ib_umem_release);
289 
ib_umem_page_count(struct ib_umem * umem)290 int ib_umem_page_count(struct ib_umem *umem)
291 {
292 	int shift;
293 	int i;
294 	int n;
295 	struct scatterlist *sg;
296 
297 	shift = ilog2(umem->page_size);
298 
299 	n = 0;
300 	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
301 		n += sg_dma_len(sg) >> shift;
302 
303 	return n;
304 }
305 EXPORT_SYMBOL(ib_umem_page_count);
306