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 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 */ 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 99 if (dmasync) 100 dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs); 101 102 if (!can_do_mlock()) 103 return ERR_PTR(-EPERM); 104 105 umem = kzalloc(sizeof *umem, GFP_KERNEL); 106 if (!umem) 107 return ERR_PTR(-ENOMEM); 108 109 umem->context = context; 110 umem->length = size; 111 umem->address = addr; 112 umem->page_size = PAGE_SIZE; 113 umem->pid = get_task_pid(current, PIDTYPE_PID); 114 /* 115 * We ask for writable memory if any of the following 116 * access flags are set. "Local write" and "remote write" 117 * obviously require write access. "Remote atomic" can do 118 * things like fetch and add, which will modify memory, and 119 * "MW bind" can change permissions by binding a window. 120 */ 121 umem->writable = !!(access & 122 (IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE | 123 IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND)); 124 125 if (access & IB_ACCESS_ON_DEMAND) { 126 ret = ib_umem_odp_get(context, umem); 127 if (ret) { 128 kfree(umem); 129 return ERR_PTR(ret); 130 } 131 return umem; 132 } 133 134 umem->odp_data = NULL; 135 136 /* We assume the memory is from hugetlb until proved otherwise */ 137 umem->hugetlb = 1; 138 139 page_list = (struct page **) __get_free_page(GFP_KERNEL); 140 if (!page_list) { 141 kfree(umem); 142 return ERR_PTR(-ENOMEM); 143 } 144 145 /* 146 * if we can't alloc the vma_list, it's not so bad; 147 * just assume the memory is not hugetlb memory 148 */ 149 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL); 150 if (!vma_list) 151 umem->hugetlb = 0; 152 153 npages = ib_umem_num_pages(umem); 154 155 down_write(¤t->mm->mmap_sem); 156 157 locked = npages + current->mm->pinned_vm; 158 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 159 160 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { 161 ret = -ENOMEM; 162 goto out; 163 } 164 165 cur_base = addr & PAGE_MASK; 166 167 if (npages == 0) { 168 ret = -EINVAL; 169 goto out; 170 } 171 172 ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL); 173 if (ret) 174 goto out; 175 176 need_release = 1; 177 sg_list_start = umem->sg_head.sgl; 178 179 while (npages) { 180 ret = get_user_pages(current, current->mm, cur_base, 181 min_t(unsigned long, npages, 182 PAGE_SIZE / sizeof (struct page *)), 183 1, !umem->writable, page_list, vma_list); 184 185 if (ret < 0) 186 goto out; 187 188 umem->npages += ret; 189 cur_base += ret * PAGE_SIZE; 190 npages -= ret; 191 192 for_each_sg(sg_list_start, sg, ret, i) { 193 if (vma_list && !is_vm_hugetlb_page(vma_list[i])) 194 umem->hugetlb = 0; 195 196 sg_set_page(sg, page_list[i], PAGE_SIZE, 0); 197 } 198 199 /* preparing for next loop */ 200 sg_list_start = sg; 201 } 202 203 umem->nmap = ib_dma_map_sg_attrs(context->device, 204 umem->sg_head.sgl, 205 umem->npages, 206 DMA_BIDIRECTIONAL, 207 &attrs); 208 209 if (umem->nmap <= 0) { 210 ret = -ENOMEM; 211 goto out; 212 } 213 214 ret = 0; 215 216 out: 217 if (ret < 0) { 218 if (need_release) 219 __ib_umem_release(context->device, umem, 0); 220 put_pid(umem->pid); 221 kfree(umem); 222 } else 223 current->mm->pinned_vm = locked; 224 225 up_write(¤t->mm->mmap_sem); 226 if (vma_list) 227 free_page((unsigned long) vma_list); 228 free_page((unsigned long) page_list); 229 230 return ret < 0 ? ERR_PTR(ret) : umem; 231 } 232 EXPORT_SYMBOL(ib_umem_get); 233 234 static void ib_umem_account(struct work_struct *work) 235 { 236 struct ib_umem *umem = container_of(work, struct ib_umem, work); 237 238 down_write(&umem->mm->mmap_sem); 239 umem->mm->pinned_vm -= umem->diff; 240 up_write(&umem->mm->mmap_sem); 241 mmput(umem->mm); 242 kfree(umem); 243 } 244 245 /** 246 * ib_umem_release - release memory pinned with ib_umem_get 247 * @umem: umem struct to release 248 */ 249 void ib_umem_release(struct ib_umem *umem) 250 { 251 struct ib_ucontext *context = umem->context; 252 struct mm_struct *mm; 253 struct task_struct *task; 254 unsigned long diff; 255 256 if (umem->odp_data) { 257 ib_umem_odp_release(umem); 258 return; 259 } 260 261 __ib_umem_release(umem->context->device, umem, 1); 262 263 task = get_pid_task(umem->pid, PIDTYPE_PID); 264 put_pid(umem->pid); 265 if (!task) 266 goto out; 267 mm = get_task_mm(task); 268 put_task_struct(task); 269 if (!mm) 270 goto out; 271 272 diff = ib_umem_num_pages(umem); 273 274 /* 275 * We may be called with the mm's mmap_sem already held. This 276 * can happen when a userspace munmap() is the call that drops 277 * the last reference to our file and calls our release 278 * method. If there are memory regions to destroy, we'll end 279 * up here and not be able to take the mmap_sem. In that case 280 * we defer the vm_locked accounting to the system workqueue. 281 */ 282 if (context->closing) { 283 if (!down_write_trylock(&mm->mmap_sem)) { 284 INIT_WORK(&umem->work, ib_umem_account); 285 umem->mm = mm; 286 umem->diff = diff; 287 288 queue_work(ib_wq, &umem->work); 289 return; 290 } 291 } else 292 down_write(&mm->mmap_sem); 293 294 mm->pinned_vm -= diff; 295 up_write(&mm->mmap_sem); 296 mmput(mm); 297 out: 298 kfree(umem); 299 } 300 EXPORT_SYMBOL(ib_umem_release); 301 302 int ib_umem_page_count(struct ib_umem *umem) 303 { 304 int shift; 305 int i; 306 int n; 307 struct scatterlist *sg; 308 309 if (umem->odp_data) 310 return ib_umem_num_pages(umem); 311 312 shift = ilog2(umem->page_size); 313 314 n = 0; 315 for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i) 316 n += sg_dma_len(sg) >> shift; 317 318 return n; 319 } 320 EXPORT_SYMBOL(ib_umem_page_count); 321 322 /* 323 * Copy from the given ib_umem's pages to the given buffer. 324 * 325 * umem - the umem to copy from 326 * offset - offset to start copying from 327 * dst - destination buffer 328 * length - buffer length 329 * 330 * Returns 0 on success, or an error code. 331 */ 332 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset, 333 size_t length) 334 { 335 size_t end = offset + length; 336 int ret; 337 338 if (offset > umem->length || length > umem->length - offset) { 339 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n", 340 offset, umem->length, end); 341 return -EINVAL; 342 } 343 344 ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length, 345 offset + ib_umem_offset(umem)); 346 347 if (ret < 0) 348 return ret; 349 else if (ret != length) 350 return -EINVAL; 351 else 352 return 0; 353 } 354 EXPORT_SYMBOL(ib_umem_copy_from); 355