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/slab.h> 41 #include <rdma/ib_umem_odp.h> 42 43 #include "uverbs.h" 44 45 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 * 73 * If access flags indicate ODP memory, avoid pinning. Instead, stores 74 * the mm for future page fault handling in conjunction with MMU notifiers. 75 * 76 * @context: userspace context to pin memory for 77 * @addr: userspace virtual address to start at 78 * @size: length of region to pin 79 * @access: IB_ACCESS_xxx flags for memory being pinned 80 * @dmasync: flush in-flight DMA when the memory region is written 81 */ 82 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr, 83 size_t size, int access, int dmasync) 84 { 85 struct ib_umem *umem; 86 struct page **page_list; 87 struct vm_area_struct **vma_list; 88 unsigned long locked; 89 unsigned long lock_limit; 90 unsigned long cur_base; 91 unsigned long npages; 92 int ret; 93 int i; 94 unsigned long dma_attrs = 0; 95 struct scatterlist *sg, *sg_list_start; 96 int need_release = 0; 97 98 if (dmasync) 99 dma_attrs |= DMA_ATTR_WRITE_BARRIER; 100 101 if (!size) 102 return ERR_PTR(-EINVAL); 103 104 /* 105 * If the combination of the addr and size requested for this memory 106 * region causes an integer overflow, return error. 107 */ 108 if (((addr + size) < addr) || 109 PAGE_ALIGN(addr + size) < (addr + size)) 110 return ERR_PTR(-EINVAL); 111 112 if (!can_do_mlock()) 113 return ERR_PTR(-EPERM); 114 115 umem = kzalloc(sizeof *umem, GFP_KERNEL); 116 if (!umem) 117 return ERR_PTR(-ENOMEM); 118 119 umem->context = context; 120 umem->length = size; 121 umem->address = addr; 122 umem->page_size = PAGE_SIZE; 123 umem->pid = get_task_pid(current, PIDTYPE_PID); 124 /* 125 * We ask for writable memory if any of the following 126 * access flags are set. "Local write" and "remote write" 127 * obviously require write access. "Remote atomic" can do 128 * things like fetch and add, which will modify memory, and 129 * "MW bind" can change permissions by binding a window. 130 */ 131 umem->writable = !!(access & 132 (IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE | 133 IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND)); 134 135 if (access & IB_ACCESS_ON_DEMAND) { 136 ret = ib_umem_odp_get(context, umem); 137 if (ret) { 138 kfree(umem); 139 return ERR_PTR(ret); 140 } 141 return umem; 142 } 143 144 umem->odp_data = NULL; 145 146 /* We assume the memory is from hugetlb until proved otherwise */ 147 umem->hugetlb = 1; 148 149 page_list = (struct page **) __get_free_page(GFP_KERNEL); 150 if (!page_list) { 151 kfree(umem); 152 return ERR_PTR(-ENOMEM); 153 } 154 155 /* 156 * if we can't alloc the vma_list, it's not so bad; 157 * just assume the memory is not hugetlb memory 158 */ 159 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL); 160 if (!vma_list) 161 umem->hugetlb = 0; 162 163 npages = ib_umem_num_pages(umem); 164 165 down_write(¤t->mm->mmap_sem); 166 167 locked = npages + current->mm->pinned_vm; 168 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 169 170 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { 171 ret = -ENOMEM; 172 goto out; 173 } 174 175 cur_base = addr & PAGE_MASK; 176 177 if (npages == 0) { 178 ret = -EINVAL; 179 goto out; 180 } 181 182 ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL); 183 if (ret) 184 goto out; 185 186 need_release = 1; 187 sg_list_start = umem->sg_head.sgl; 188 189 while (npages) { 190 ret = get_user_pages(cur_base, 191 min_t(unsigned long, npages, 192 PAGE_SIZE / sizeof (struct page *)), 193 1, !umem->writable, page_list, vma_list); 194 195 if (ret < 0) 196 goto out; 197 198 umem->npages += ret; 199 cur_base += ret * PAGE_SIZE; 200 npages -= ret; 201 202 for_each_sg(sg_list_start, sg, ret, i) { 203 if (vma_list && !is_vm_hugetlb_page(vma_list[i])) 204 umem->hugetlb = 0; 205 206 sg_set_page(sg, page_list[i], PAGE_SIZE, 0); 207 } 208 209 /* preparing for next loop */ 210 sg_list_start = sg; 211 } 212 213 umem->nmap = ib_dma_map_sg_attrs(context->device, 214 umem->sg_head.sgl, 215 umem->npages, 216 DMA_BIDIRECTIONAL, 217 dma_attrs); 218 219 if (umem->nmap <= 0) { 220 ret = -ENOMEM; 221 goto out; 222 } 223 224 ret = 0; 225 226 out: 227 if (ret < 0) { 228 if (need_release) 229 __ib_umem_release(context->device, umem, 0); 230 put_pid(umem->pid); 231 kfree(umem); 232 } else 233 current->mm->pinned_vm = locked; 234 235 up_write(¤t->mm->mmap_sem); 236 if (vma_list) 237 free_page((unsigned long) vma_list); 238 free_page((unsigned long) page_list); 239 240 return ret < 0 ? ERR_PTR(ret) : umem; 241 } 242 EXPORT_SYMBOL(ib_umem_get); 243 244 static void ib_umem_account(struct work_struct *work) 245 { 246 struct ib_umem *umem = container_of(work, struct ib_umem, work); 247 248 down_write(&umem->mm->mmap_sem); 249 umem->mm->pinned_vm -= umem->diff; 250 up_write(&umem->mm->mmap_sem); 251 mmput(umem->mm); 252 kfree(umem); 253 } 254 255 /** 256 * ib_umem_release - release memory pinned with ib_umem_get 257 * @umem: umem struct to release 258 */ 259 void ib_umem_release(struct ib_umem *umem) 260 { 261 struct ib_ucontext *context = umem->context; 262 struct mm_struct *mm; 263 struct task_struct *task; 264 unsigned long diff; 265 266 if (umem->odp_data) { 267 ib_umem_odp_release(umem); 268 return; 269 } 270 271 __ib_umem_release(umem->context->device, umem, 1); 272 273 task = get_pid_task(umem->pid, PIDTYPE_PID); 274 put_pid(umem->pid); 275 if (!task) 276 goto out; 277 mm = get_task_mm(task); 278 put_task_struct(task); 279 if (!mm) 280 goto out; 281 282 diff = ib_umem_num_pages(umem); 283 284 /* 285 * We may be called with the mm's mmap_sem already held. This 286 * can happen when a userspace munmap() is the call that drops 287 * the last reference to our file and calls our release 288 * method. If there are memory regions to destroy, we'll end 289 * up here and not be able to take the mmap_sem. In that case 290 * we defer the vm_locked accounting to the system workqueue. 291 */ 292 if (context->closing) { 293 if (!down_write_trylock(&mm->mmap_sem)) { 294 INIT_WORK(&umem->work, ib_umem_account); 295 umem->mm = mm; 296 umem->diff = diff; 297 298 queue_work(ib_wq, &umem->work); 299 return; 300 } 301 } else 302 down_write(&mm->mmap_sem); 303 304 mm->pinned_vm -= diff; 305 up_write(&mm->mmap_sem); 306 mmput(mm); 307 out: 308 kfree(umem); 309 } 310 EXPORT_SYMBOL(ib_umem_release); 311 312 int ib_umem_page_count(struct ib_umem *umem) 313 { 314 int shift; 315 int i; 316 int n; 317 struct scatterlist *sg; 318 319 if (umem->odp_data) 320 return ib_umem_num_pages(umem); 321 322 shift = ilog2(umem->page_size); 323 324 n = 0; 325 for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i) 326 n += sg_dma_len(sg) >> shift; 327 328 return n; 329 } 330 EXPORT_SYMBOL(ib_umem_page_count); 331 332 /* 333 * Copy from the given ib_umem's pages to the given buffer. 334 * 335 * umem - the umem to copy from 336 * offset - offset to start copying from 337 * dst - destination buffer 338 * length - buffer length 339 * 340 * Returns 0 on success, or an error code. 341 */ 342 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset, 343 size_t length) 344 { 345 size_t end = offset + length; 346 int ret; 347 348 if (offset > umem->length || length > umem->length - offset) { 349 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n", 350 offset, umem->length, end); 351 return -EINVAL; 352 } 353 354 ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length, 355 offset + ib_umem_offset(umem)); 356 357 if (ret < 0) 358 return ret; 359 else if (ret != length) 360 return -EINVAL; 361 else 362 return 0; 363 } 364 EXPORT_SYMBOL(ib_umem_copy_from); 365