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