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 (!size) 103 return ERR_PTR(-EINVAL); 104 105 /* 106 * If the combination of the addr and size requested for this memory 107 * region causes an integer overflow, return error. 108 */ 109 if (((addr + size) < addr) || 110 PAGE_ALIGN(addr + size) < (addr + size)) 111 return ERR_PTR(-EINVAL); 112 113 if (!can_do_mlock()) 114 return ERR_PTR(-EPERM); 115 116 umem = kzalloc(sizeof *umem, GFP_KERNEL); 117 if (!umem) 118 return ERR_PTR(-ENOMEM); 119 120 umem->context = context; 121 umem->length = size; 122 umem->address = addr; 123 umem->page_size = PAGE_SIZE; 124 umem->pid = get_task_pid(current, PIDTYPE_PID); 125 /* 126 * We ask for writable memory if any of the following 127 * access flags are set. "Local write" and "remote write" 128 * obviously require write access. "Remote atomic" can do 129 * things like fetch and add, which will modify memory, and 130 * "MW bind" can change permissions by binding a window. 131 */ 132 umem->writable = !!(access & 133 (IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE | 134 IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND)); 135 136 if (access & IB_ACCESS_ON_DEMAND) { 137 ret = ib_umem_odp_get(context, umem); 138 if (ret) { 139 kfree(umem); 140 return ERR_PTR(ret); 141 } 142 return umem; 143 } 144 145 umem->odp_data = NULL; 146 147 /* We assume the memory is from hugetlb until proved otherwise */ 148 umem->hugetlb = 1; 149 150 page_list = (struct page **) __get_free_page(GFP_KERNEL); 151 if (!page_list) { 152 kfree(umem); 153 return ERR_PTR(-ENOMEM); 154 } 155 156 /* 157 * if we can't alloc the vma_list, it's not so bad; 158 * just assume the memory is not hugetlb memory 159 */ 160 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL); 161 if (!vma_list) 162 umem->hugetlb = 0; 163 164 npages = ib_umem_num_pages(umem); 165 166 down_write(¤t->mm->mmap_sem); 167 168 locked = npages + current->mm->pinned_vm; 169 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 170 171 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { 172 ret = -ENOMEM; 173 goto out; 174 } 175 176 cur_base = addr & PAGE_MASK; 177 178 if (npages == 0) { 179 ret = -EINVAL; 180 goto out; 181 } 182 183 ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL); 184 if (ret) 185 goto out; 186 187 need_release = 1; 188 sg_list_start = umem->sg_head.sgl; 189 190 while (npages) { 191 ret = get_user_pages(current, current->mm, cur_base, 192 min_t(unsigned long, npages, 193 PAGE_SIZE / sizeof (struct page *)), 194 1, !umem->writable, page_list, vma_list); 195 196 if (ret < 0) 197 goto out; 198 199 umem->npages += ret; 200 cur_base += ret * PAGE_SIZE; 201 npages -= ret; 202 203 for_each_sg(sg_list_start, sg, ret, i) { 204 if (vma_list && !is_vm_hugetlb_page(vma_list[i])) 205 umem->hugetlb = 0; 206 207 sg_set_page(sg, page_list[i], PAGE_SIZE, 0); 208 } 209 210 /* preparing for next loop */ 211 sg_list_start = sg; 212 } 213 214 umem->nmap = ib_dma_map_sg_attrs(context->device, 215 umem->sg_head.sgl, 216 umem->npages, 217 DMA_BIDIRECTIONAL, 218 &attrs); 219 220 if (umem->nmap <= 0) { 221 ret = -ENOMEM; 222 goto out; 223 } 224 225 ret = 0; 226 227 out: 228 if (ret < 0) { 229 if (need_release) 230 __ib_umem_release(context->device, umem, 0); 231 put_pid(umem->pid); 232 kfree(umem); 233 } else 234 current->mm->pinned_vm = locked; 235 236 up_write(¤t->mm->mmap_sem); 237 if (vma_list) 238 free_page((unsigned long) vma_list); 239 free_page((unsigned long) page_list); 240 241 return ret < 0 ? ERR_PTR(ret) : umem; 242 } 243 EXPORT_SYMBOL(ib_umem_get); 244 245 static void ib_umem_account(struct work_struct *work) 246 { 247 struct ib_umem *umem = container_of(work, struct ib_umem, work); 248 249 down_write(&umem->mm->mmap_sem); 250 umem->mm->pinned_vm -= umem->diff; 251 up_write(&umem->mm->mmap_sem); 252 mmput(umem->mm); 253 kfree(umem); 254 } 255 256 /** 257 * ib_umem_release - release memory pinned with ib_umem_get 258 * @umem: umem struct to release 259 */ 260 void ib_umem_release(struct ib_umem *umem) 261 { 262 struct ib_ucontext *context = umem->context; 263 struct mm_struct *mm; 264 struct task_struct *task; 265 unsigned long diff; 266 267 if (umem->odp_data) { 268 ib_umem_odp_release(umem); 269 return; 270 } 271 272 __ib_umem_release(umem->context->device, umem, 1); 273 274 task = get_pid_task(umem->pid, PIDTYPE_PID); 275 put_pid(umem->pid); 276 if (!task) 277 goto out; 278 mm = get_task_mm(task); 279 put_task_struct(task); 280 if (!mm) 281 goto out; 282 283 diff = ib_umem_num_pages(umem); 284 285 /* 286 * We may be called with the mm's mmap_sem already held. This 287 * can happen when a userspace munmap() is the call that drops 288 * the last reference to our file and calls our release 289 * method. If there are memory regions to destroy, we'll end 290 * up here and not be able to take the mmap_sem. In that case 291 * we defer the vm_locked accounting to the system workqueue. 292 */ 293 if (context->closing) { 294 if (!down_write_trylock(&mm->mmap_sem)) { 295 INIT_WORK(&umem->work, ib_umem_account); 296 umem->mm = mm; 297 umem->diff = diff; 298 299 queue_work(ib_wq, &umem->work); 300 return; 301 } 302 } else 303 down_write(&mm->mmap_sem); 304 305 mm->pinned_vm -= diff; 306 up_write(&mm->mmap_sem); 307 mmput(mm); 308 out: 309 kfree(umem); 310 } 311 EXPORT_SYMBOL(ib_umem_release); 312 313 int ib_umem_page_count(struct ib_umem *umem) 314 { 315 int shift; 316 int i; 317 int n; 318 struct scatterlist *sg; 319 320 if (umem->odp_data) 321 return ib_umem_num_pages(umem); 322 323 shift = ilog2(umem->page_size); 324 325 n = 0; 326 for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i) 327 n += sg_dma_len(sg) >> shift; 328 329 return n; 330 } 331 EXPORT_SYMBOL(ib_umem_page_count); 332 333 /* 334 * Copy from the given ib_umem's pages to the given buffer. 335 * 336 * umem - the umem to copy from 337 * offset - offset to start copying from 338 * dst - destination buffer 339 * length - buffer length 340 * 341 * Returns 0 on success, or an error code. 342 */ 343 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset, 344 size_t length) 345 { 346 size_t end = offset + length; 347 int ret; 348 349 if (offset > umem->length || length > umem->length - offset) { 350 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n", 351 offset, umem->length, end); 352 return -EINVAL; 353 } 354 355 ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length, 356 offset + ib_umem_offset(umem)); 357 358 if (ret < 0) 359 return ret; 360 else if (ret != length) 361 return -EINVAL; 362 else 363 return 0; 364 } 365 EXPORT_SYMBOL(ib_umem_copy_from); 366