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/export.h> 39 #include <linux/hugetlb.h> 40 #include <linux/dma-attrs.h> 41 #include <linux/slab.h> 42 43 #include "uverbs.h" 44 45 #define IB_UMEM_MAX_PAGE_CHUNK \ 46 ((PAGE_SIZE - offsetof(struct ib_umem_chunk, page_list)) / \ 47 ((void *) &((struct ib_umem_chunk *) 0)->page_list[1] - \ 48 (void *) &((struct ib_umem_chunk *) 0)->page_list[0])) 49 50 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty) 51 { 52 struct ib_umem_chunk *chunk, *tmp; 53 int i; 54 55 list_for_each_entry_safe(chunk, tmp, &umem->chunk_list, list) { 56 ib_dma_unmap_sg(dev, chunk->page_list, 57 chunk->nents, DMA_BIDIRECTIONAL); 58 for (i = 0; i < chunk->nents; ++i) { 59 struct page *page = sg_page(&chunk->page_list[i]); 60 61 if (umem->writable && dirty) 62 set_page_dirty_lock(page); 63 put_page(page); 64 } 65 66 kfree(chunk); 67 } 68 } 69 70 /** 71 * ib_umem_get - Pin and DMA map userspace memory. 72 * @context: userspace context to pin memory for 73 * @addr: userspace virtual address to start at 74 * @size: length of region to pin 75 * @access: IB_ACCESS_xxx flags for memory being pinned 76 * @dmasync: flush in-flight DMA when the memory region is written 77 */ 78 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr, 79 size_t size, int access, int dmasync) 80 { 81 struct ib_umem *umem; 82 struct page **page_list; 83 struct vm_area_struct **vma_list; 84 struct ib_umem_chunk *chunk; 85 unsigned long locked; 86 unsigned long lock_limit; 87 unsigned long cur_base; 88 unsigned long npages; 89 int ret; 90 int off; 91 int i; 92 DEFINE_DMA_ATTRS(attrs); 93 94 if (dmasync) 95 dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs); 96 97 if (!can_do_mlock()) 98 return ERR_PTR(-EPERM); 99 100 umem = kmalloc(sizeof *umem, GFP_KERNEL); 101 if (!umem) 102 return ERR_PTR(-ENOMEM); 103 104 umem->context = context; 105 umem->length = size; 106 umem->offset = addr & ~PAGE_MASK; 107 umem->page_size = PAGE_SIZE; 108 /* 109 * We ask for writable memory if any access flags other than 110 * "remote read" are set. "Local write" and "remote write" 111 * obviously require write access. "Remote atomic" can do 112 * things like fetch and add, which will modify memory, and 113 * "MW bind" can change permissions by binding a window. 114 */ 115 umem->writable = !!(access & ~IB_ACCESS_REMOTE_READ); 116 117 /* We assume the memory is from hugetlb until proved otherwise */ 118 umem->hugetlb = 1; 119 120 INIT_LIST_HEAD(&umem->chunk_list); 121 122 page_list = (struct page **) __get_free_page(GFP_KERNEL); 123 if (!page_list) { 124 kfree(umem); 125 return ERR_PTR(-ENOMEM); 126 } 127 128 /* 129 * if we can't alloc the vma_list, it's not so bad; 130 * just assume the memory is not hugetlb memory 131 */ 132 vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL); 133 if (!vma_list) 134 umem->hugetlb = 0; 135 136 npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT; 137 138 down_write(¤t->mm->mmap_sem); 139 140 locked = npages + current->mm->pinned_vm; 141 lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 142 143 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { 144 ret = -ENOMEM; 145 goto out; 146 } 147 148 cur_base = addr & PAGE_MASK; 149 150 ret = 0; 151 while (npages) { 152 ret = get_user_pages(current, current->mm, cur_base, 153 min_t(unsigned long, npages, 154 PAGE_SIZE / sizeof (struct page *)), 155 1, !umem->writable, page_list, vma_list); 156 157 if (ret < 0) 158 goto out; 159 160 cur_base += ret * PAGE_SIZE; 161 npages -= ret; 162 163 off = 0; 164 165 while (ret) { 166 chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) * 167 min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK), 168 GFP_KERNEL); 169 if (!chunk) { 170 ret = -ENOMEM; 171 goto out; 172 } 173 174 chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK); 175 sg_init_table(chunk->page_list, chunk->nents); 176 for (i = 0; i < chunk->nents; ++i) { 177 if (vma_list && 178 !is_vm_hugetlb_page(vma_list[i + off])) 179 umem->hugetlb = 0; 180 sg_set_page(&chunk->page_list[i], page_list[i + off], PAGE_SIZE, 0); 181 } 182 183 chunk->nmap = ib_dma_map_sg_attrs(context->device, 184 &chunk->page_list[0], 185 chunk->nents, 186 DMA_BIDIRECTIONAL, 187 &attrs); 188 if (chunk->nmap <= 0) { 189 for (i = 0; i < chunk->nents; ++i) 190 put_page(sg_page(&chunk->page_list[i])); 191 kfree(chunk); 192 193 ret = -ENOMEM; 194 goto out; 195 } 196 197 ret -= chunk->nents; 198 off += chunk->nents; 199 list_add_tail(&chunk->list, &umem->chunk_list); 200 } 201 202 ret = 0; 203 } 204 205 out: 206 if (ret < 0) { 207 __ib_umem_release(context->device, umem, 0); 208 kfree(umem); 209 } else 210 current->mm->pinned_vm = locked; 211 212 up_write(¤t->mm->mmap_sem); 213 if (vma_list) 214 free_page((unsigned long) vma_list); 215 free_page((unsigned long) page_list); 216 217 return ret < 0 ? ERR_PTR(ret) : umem; 218 } 219 EXPORT_SYMBOL(ib_umem_get); 220 221 static void ib_umem_account(struct work_struct *work) 222 { 223 struct ib_umem *umem = container_of(work, struct ib_umem, work); 224 225 down_write(&umem->mm->mmap_sem); 226 umem->mm->pinned_vm -= umem->diff; 227 up_write(&umem->mm->mmap_sem); 228 mmput(umem->mm); 229 kfree(umem); 230 } 231 232 /** 233 * ib_umem_release - release memory pinned with ib_umem_get 234 * @umem: umem struct to release 235 */ 236 void ib_umem_release(struct ib_umem *umem) 237 { 238 struct ib_ucontext *context = umem->context; 239 struct mm_struct *mm; 240 unsigned long diff; 241 242 __ib_umem_release(umem->context->device, umem, 1); 243 244 mm = get_task_mm(current); 245 if (!mm) { 246 kfree(umem); 247 return; 248 } 249 250 diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT; 251 252 /* 253 * We may be called with the mm's mmap_sem already held. This 254 * can happen when a userspace munmap() is the call that drops 255 * the last reference to our file and calls our release 256 * method. If there are memory regions to destroy, we'll end 257 * up here and not be able to take the mmap_sem. In that case 258 * we defer the vm_locked accounting to the system workqueue. 259 */ 260 if (context->closing) { 261 if (!down_write_trylock(&mm->mmap_sem)) { 262 INIT_WORK(&umem->work, ib_umem_account); 263 umem->mm = mm; 264 umem->diff = diff; 265 266 queue_work(ib_wq, &umem->work); 267 return; 268 } 269 } else 270 down_write(&mm->mmap_sem); 271 272 current->mm->pinned_vm -= diff; 273 up_write(&mm->mmap_sem); 274 mmput(mm); 275 kfree(umem); 276 } 277 EXPORT_SYMBOL(ib_umem_release); 278 279 int ib_umem_page_count(struct ib_umem *umem) 280 { 281 struct ib_umem_chunk *chunk; 282 int shift; 283 int i; 284 int n; 285 286 shift = ilog2(umem->page_size); 287 288 n = 0; 289 list_for_each_entry(chunk, &umem->chunk_list, list) 290 for (i = 0; i < chunk->nmap; ++i) 291 n += sg_dma_len(&chunk->page_list[i]) >> shift; 292 293 return n; 294 } 295 EXPORT_SYMBOL(ib_umem_page_count); 296