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