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/hugetlb.h> 39#include <linux/dma-attrs.h> 40#include <linux/slab.h> 41 42#include "uverbs.h" 43 44#define IB_UMEM_MAX_PAGE_CHUNK \ 45 ((PAGE_SIZE - offsetof(struct ib_umem_chunk, page_list)) / \ 46 ((void *) &((struct ib_umem_chunk *) 0)->page_list[1] - \ 47 (void *) &((struct ib_umem_chunk *) 0)->page_list[0])) 48 49static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty) 50{ 51 struct ib_umem_chunk *chunk, *tmp; 52 int i; 53 54 list_for_each_entry_safe(chunk, tmp, &umem->chunk_list, list) { 55 ib_dma_unmap_sg(dev, chunk->page_list, 56 chunk->nents, DMA_BIDIRECTIONAL); 57 for (i = 0; i < chunk->nents; ++i) { 58 struct page *page = sg_page(&chunk->page_list[i]); 59 60 if (umem->writable && dirty) 61 set_page_dirty_lock(page); 62 put_page(page); 63 } 64 65 kfree(chunk); 66 } 67} 68 69/** 70 * ib_umem_get - Pin and DMA map userspace memory. 71 * @context: userspace context to pin memory for 72 * @addr: userspace virtual address to start at 73 * @size: length of region to pin 74 * @access: IB_ACCESS_xxx flags for memory being pinned 75 * @dmasync: flush in-flight DMA when the memory region is written 76 */ 77struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr, 78 size_t size, int access, int dmasync) 79{ 80 struct ib_umem *umem; 81 struct page **page_list; 82 struct vm_area_struct **vma_list; 83 struct ib_umem_chunk *chunk; 84 unsigned long locked; 85 unsigned long lock_limit; 86 unsigned long cur_base; 87 unsigned long npages; 88 int ret; 89 int off; 90 int i; 91 DEFINE_DMA_ATTRS(attrs); 92 93 if (dmasync) 94 dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs); 95 96 if (!can_do_mlock()) 97 return ERR_PTR(-EPERM); 98 99 umem = kmalloc(sizeof *umem, GFP_KERNEL); 100 if (!umem) 101 return ERR_PTR(-ENOMEM); 102 103 umem->context = context; 104 umem->length = size; 105 umem->offset = addr & ~PAGE_MASK; 106 umem->page_size = PAGE_SIZE; 107 /* 108 * We ask for writable memory if any access flags other than 109 * "remote read" are set. "Local write" and "remote write" 110 * obviously require write access. "Remote atomic" can do 111 * things like fetch and add, which will modify memory, and 112 * "MW bind" can change permissions by binding a window. 113 */ 114 umem->writable = !!(access & ~IB_ACCESS_REMOTE_READ); 115 116 /* We assume the memory is from hugetlb until proved otherwise */ 117 umem->hugetlb = 1; 118 119 INIT_LIST_HEAD(&umem->chunk_list); 120 121 page_list = (struct page **) __get_free_page(GFP_KERNEL); 122 if (!page_list) { 123 kfree(umem); 124 return ERR_PTR(-ENOMEM); 125 } 126 127 /* 128 * if we can't alloc the vma_list, it's not so bad; 129 * just assume the memory is not hugetlb memory 130 */ 131 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL); 132 if (!vma_list) 133 umem->hugetlb = 0; 134 135 npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT; 136 137 down_write(¤t->mm->mmap_sem); 138 139 locked = npages + current->mm->locked_vm; 140 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 141 142 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { 143 ret = -ENOMEM; 144 goto out; 145 } 146 147 cur_base = addr & PAGE_MASK; 148 149 ret = 0; 150 while (npages) { 151 ret = get_user_pages(current, current->mm, cur_base, 152 min_t(unsigned long, npages, 153 PAGE_SIZE / sizeof (struct page *)), 154 1, !umem->writable, page_list, vma_list); 155 156 if (ret < 0) 157 goto out; 158 159 cur_base += ret * PAGE_SIZE; 160 npages -= ret; 161 162 off = 0; 163 164 while (ret) { 165 chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) * 166 min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK), 167 GFP_KERNEL); 168 if (!chunk) { 169 ret = -ENOMEM; 170 goto out; 171 } 172 173 chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK); 174 sg_init_table(chunk->page_list, chunk->nents); 175 for (i = 0; i < chunk->nents; ++i) { 176 if (vma_list && 177 !is_vm_hugetlb_page(vma_list[i + off])) 178 umem->hugetlb = 0; 179 sg_set_page(&chunk->page_list[i], page_list[i + off], PAGE_SIZE, 0); 180 } 181 182 chunk->nmap = ib_dma_map_sg_attrs(context->device, 183 &chunk->page_list[0], 184 chunk->nents, 185 DMA_BIDIRECTIONAL, 186 &attrs); 187 if (chunk->nmap <= 0) { 188 for (i = 0; i < chunk->nents; ++i) 189 put_page(sg_page(&chunk->page_list[i])); 190 kfree(chunk); 191 192 ret = -ENOMEM; 193 goto out; 194 } 195 196 ret -= chunk->nents; 197 off += chunk->nents; 198 list_add_tail(&chunk->list, &umem->chunk_list); 199 } 200 201 ret = 0; 202 } 203 204out: 205 if (ret < 0) { 206 __ib_umem_release(context->device, umem, 0); 207 kfree(umem); 208 } else 209 current->mm->locked_vm = locked; 210 211 up_write(¤t->mm->mmap_sem); 212 if (vma_list) 213 free_page((unsigned long) vma_list); 214 free_page((unsigned long) page_list); 215 216 return ret < 0 ? ERR_PTR(ret) : umem; 217} 218EXPORT_SYMBOL(ib_umem_get); 219 220static void ib_umem_account(struct work_struct *work) 221{ 222 struct ib_umem *umem = container_of(work, struct ib_umem, work); 223 224 down_write(&umem->mm->mmap_sem); 225 umem->mm->locked_vm -= umem->diff; 226 up_write(&umem->mm->mmap_sem); 227 mmput(umem->mm); 228 kfree(umem); 229} 230 231/** 232 * ib_umem_release - release memory pinned with ib_umem_get 233 * @umem: umem struct to release 234 */ 235void ib_umem_release(struct ib_umem *umem) 236{ 237 struct ib_ucontext *context = umem->context; 238 struct mm_struct *mm; 239 unsigned long diff; 240 241 __ib_umem_release(umem->context->device, umem, 1); 242 243 mm = get_task_mm(current); 244 if (!mm) { 245 kfree(umem); 246 return; 247 } 248 249 diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT; 250 251 /* 252 * We may be called with the mm's mmap_sem already held. This 253 * can happen when a userspace munmap() is the call that drops 254 * the last reference to our file and calls our release 255 * method. If there are memory regions to destroy, we'll end 256 * up here and not be able to take the mmap_sem. In that case 257 * we defer the vm_locked accounting to the system workqueue. 258 */ 259 if (context->closing) { 260 if (!down_write_trylock(&mm->mmap_sem)) { 261 INIT_WORK(&umem->work, ib_umem_account); 262 umem->mm = mm; 263 umem->diff = diff; 264 265 schedule_work(&umem->work); 266 return; 267 } 268 } else 269 down_write(&mm->mmap_sem); 270 271 current->mm->locked_vm -= diff; 272 up_write(&mm->mmap_sem); 273 mmput(mm); 274 kfree(umem); 275} 276EXPORT_SYMBOL(ib_umem_release); 277 278int ib_umem_page_count(struct ib_umem *umem) 279{ 280 struct ib_umem_chunk *chunk; 281 int shift; 282 int i; 283 int n; 284 285 shift = ilog2(umem->page_size); 286 287 n = 0; 288 list_for_each_entry(chunk, &umem->chunk_list, list) 289 for (i = 0; i < chunk->nmap; ++i) 290 n += sg_dma_len(&chunk->page_list[i]) >> shift; 291 292 return n; 293} 294EXPORT_SYMBOL(ib_umem_page_count); 295