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