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 * $Id: uverbs_mem.c 2743 2005-06-28 22:27:59Z roland $ 35 */ 36 37 #include <linux/mm.h> 38 #include <linux/dma-mapping.h> 39 #include <linux/sched.h> 40 #include <linux/hugetlb.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 49 static 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 if (umem->writable && dirty) 59 set_page_dirty_lock(chunk->page_list[i].page); 60 put_page(chunk->page_list[i].page); 61 } 62 63 kfree(chunk); 64 } 65 } 66 67 /** 68 * ib_umem_get - Pin and DMA map userspace memory. 69 * @context: userspace context to pin memory for 70 * @addr: userspace virtual address to start at 71 * @size: length of region to pin 72 * @access: IB_ACCESS_xxx flags for memory being pinned 73 */ 74 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr, 75 size_t size, int access) 76 { 77 struct ib_umem *umem; 78 struct page **page_list; 79 struct vm_area_struct **vma_list; 80 struct ib_umem_chunk *chunk; 81 unsigned long locked; 82 unsigned long lock_limit; 83 unsigned long cur_base; 84 unsigned long npages; 85 int ret; 86 int off; 87 int i; 88 89 if (!can_do_mlock()) 90 return ERR_PTR(-EPERM); 91 92 umem = kmalloc(sizeof *umem, GFP_KERNEL); 93 if (!umem) 94 return ERR_PTR(-ENOMEM); 95 96 umem->context = context; 97 umem->length = size; 98 umem->offset = addr & ~PAGE_MASK; 99 umem->page_size = PAGE_SIZE; 100 /* 101 * We ask for writable memory if any access flags other than 102 * "remote read" are set. "Local write" and "remote write" 103 * obviously require write access. "Remote atomic" can do 104 * things like fetch and add, which will modify memory, and 105 * "MW bind" can change permissions by binding a window. 106 */ 107 umem->writable = !!(access & ~IB_ACCESS_REMOTE_READ); 108 109 /* We assume the memory is from hugetlb until proved otherwise */ 110 umem->hugetlb = 1; 111 112 INIT_LIST_HEAD(&umem->chunk_list); 113 114 page_list = (struct page **) __get_free_page(GFP_KERNEL); 115 if (!page_list) { 116 kfree(umem); 117 return ERR_PTR(-ENOMEM); 118 } 119 120 /* 121 * if we can't alloc the vma_list, it's not so bad; 122 * just assume the memory is not hugetlb memory 123 */ 124 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL); 125 if (!vma_list) 126 umem->hugetlb = 0; 127 128 npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT; 129 130 down_write(¤t->mm->mmap_sem); 131 132 locked = npages + current->mm->locked_vm; 133 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; 134 135 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { 136 ret = -ENOMEM; 137 goto out; 138 } 139 140 cur_base = addr & PAGE_MASK; 141 142 ret = 0; 143 while (npages) { 144 ret = get_user_pages(current, current->mm, cur_base, 145 min_t(int, npages, 146 PAGE_SIZE / sizeof (struct page *)), 147 1, !umem->writable, page_list, vma_list); 148 149 if (ret < 0) 150 goto out; 151 152 cur_base += ret * PAGE_SIZE; 153 npages -= ret; 154 155 off = 0; 156 157 while (ret) { 158 chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) * 159 min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK), 160 GFP_KERNEL); 161 if (!chunk) { 162 ret = -ENOMEM; 163 goto out; 164 } 165 166 chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK); 167 for (i = 0; i < chunk->nents; ++i) { 168 if (vma_list && 169 !is_vm_hugetlb_page(vma_list[i + off])) 170 umem->hugetlb = 0; 171 chunk->page_list[i].page = page_list[i + off]; 172 chunk->page_list[i].offset = 0; 173 chunk->page_list[i].length = PAGE_SIZE; 174 } 175 176 chunk->nmap = ib_dma_map_sg(context->device, 177 &chunk->page_list[0], 178 chunk->nents, 179 DMA_BIDIRECTIONAL); 180 if (chunk->nmap <= 0) { 181 for (i = 0; i < chunk->nents; ++i) 182 put_page(chunk->page_list[i].page); 183 kfree(chunk); 184 185 ret = -ENOMEM; 186 goto out; 187 } 188 189 ret -= chunk->nents; 190 off += chunk->nents; 191 list_add_tail(&chunk->list, &umem->chunk_list); 192 } 193 194 ret = 0; 195 } 196 197 out: 198 if (ret < 0) { 199 __ib_umem_release(context->device, umem, 0); 200 kfree(umem); 201 } else 202 current->mm->locked_vm = locked; 203 204 up_write(¤t->mm->mmap_sem); 205 if (vma_list) 206 free_page((unsigned long) vma_list); 207 free_page((unsigned long) page_list); 208 209 return ret < 0 ? ERR_PTR(ret) : umem; 210 } 211 EXPORT_SYMBOL(ib_umem_get); 212 213 static void ib_umem_account(struct work_struct *work) 214 { 215 struct ib_umem *umem = container_of(work, struct ib_umem, work); 216 217 down_write(&umem->mm->mmap_sem); 218 umem->mm->locked_vm -= umem->diff; 219 up_write(&umem->mm->mmap_sem); 220 mmput(umem->mm); 221 kfree(umem); 222 } 223 224 /** 225 * ib_umem_release - release memory pinned with ib_umem_get 226 * @umem: umem struct to release 227 */ 228 void ib_umem_release(struct ib_umem *umem) 229 { 230 struct ib_ucontext *context = umem->context; 231 struct mm_struct *mm; 232 unsigned long diff; 233 234 __ib_umem_release(umem->context->device, umem, 1); 235 236 mm = get_task_mm(current); 237 if (!mm) { 238 kfree(umem); 239 return; 240 } 241 242 diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT; 243 244 /* 245 * We may be called with the mm's mmap_sem already held. This 246 * can happen when a userspace munmap() is the call that drops 247 * the last reference to our file and calls our release 248 * method. If there are memory regions to destroy, we'll end 249 * up here and not be able to take the mmap_sem. In that case 250 * we defer the vm_locked accounting to the system workqueue. 251 */ 252 if (context->closing) { 253 if (!down_write_trylock(&mm->mmap_sem)) { 254 INIT_WORK(&umem->work, ib_umem_account); 255 umem->mm = mm; 256 umem->diff = diff; 257 258 schedule_work(&umem->work); 259 return; 260 } 261 } else 262 down_write(&mm->mmap_sem); 263 264 current->mm->locked_vm -= diff; 265 up_write(&mm->mmap_sem); 266 mmput(mm); 267 kfree(umem); 268 } 269 EXPORT_SYMBOL(ib_umem_release); 270 271 int ib_umem_page_count(struct ib_umem *umem) 272 { 273 struct ib_umem_chunk *chunk; 274 int shift; 275 int i; 276 int n; 277 278 shift = ilog2(umem->page_size); 279 280 n = 0; 281 list_for_each_entry(chunk, &umem->chunk_list, list) 282 for (i = 0; i < chunk->nmap; ++i) 283 n += sg_dma_len(&chunk->page_list[i]) >> shift; 284 285 return n; 286 } 287 EXPORT_SYMBOL(ib_umem_page_count); 288