drivers/infiniband/core/umem.c

   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(&current->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]);
 175                                 chunk->page_list[i].offset = 0;
 176                                 chunk->page_list[i].length = PAGE_SIZE;
 177                         }
 178
 179                         chunk->nmap = ib_dma_map_sg(context->device,
 180                                                     &chunk->page_list[0],
 181                                                     chunk->nents,
 182                                                     DMA_BIDIRECTIONAL);
 183                         if (chunk->nmap <= 0) {
 184                                 for (i = 0; i < chunk->nents; ++i)
 185                                         put_page(sg_page(&chunk->page_list[i]));
 186                                 kfree(chunk);
 187
 188                                 ret = -ENOMEM;
 189                                 goto out;
 190                         }
 191
 192                         ret -= chunk->nents;
 193                         off += chunk->nents;
 194                         list_add_tail(&chunk->list, &umem->chunk_list);
 195                 }
 196
 197                 ret = 0;
 198         }
 199
 200 out:
 201         if (ret < 0) {
 202                 __ib_umem_release(context->device, umem, 0);
 203                 kfree(umem);
 204         } else
 205                 current->mm->locked_vm = locked;
 206
 207         up_write(&current->mm->mmap_sem);
 208         if (vma_list)
 209                 free_page((unsigned long) vma_list);
 210         free_page((unsigned long) page_list);
 211
 212         return ret < 0 ? ERR_PTR(ret) : umem;
 213 }
 214 EXPORT_SYMBOL(ib_umem_get);
 215
 216 static void ib_umem_account(struct work_struct *work)
 217 {
 218         struct ib_umem *umem = container_of(work, struct ib_umem, work);
 219
 220         down_write(&umem->mm->mmap_sem);
 221         umem->mm->locked_vm -= umem->diff;
 222         up_write(&umem->mm->mmap_sem);
 223         mmput(umem->mm);
 224         kfree(umem);
 225 }
 226
 227 /**
 228  * ib_umem_release - release memory pinned with ib_umem_get
 229  * @umem: umem struct to release
 230  */
 231 void ib_umem_release(struct ib_umem *umem)
 232 {
 233         struct ib_ucontext *context = umem->context;
 234         struct mm_struct *mm;
 235         unsigned long diff;
 236
 237         __ib_umem_release(umem->context->device, umem, 1);
 238
 239         mm = get_task_mm(current);
 240         if (!mm) {
 241                 kfree(umem);
 242                 return;
 243         }
 244
 245         diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
 246
 247         /*
 248          * We may be called with the mm's mmap_sem already held.  This
 249          * can happen when a userspace munmap() is the call that drops
 250          * the last reference to our file and calls our release
 251          * method.  If there are memory regions to destroy, we'll end
 252          * up here and not be able to take the mmap_sem.  In that case
 253          * we defer the vm_locked accounting to the system workqueue.
 254          */
 255         if (context->closing) {
 256                 if (!down_write_trylock(&mm->mmap_sem)) {
 257                         INIT_WORK(&umem->work, ib_umem_account);
 258                         umem->mm   = mm;
 259                         umem->diff = diff;
 260
 261                         schedule_work(&umem->work);
 262                         return;
 263                 }
 264         } else
 265                 down_write(&mm->mmap_sem);
 266
 267         current->mm->locked_vm -= diff;
 268         up_write(&mm->mmap_sem);
 269         mmput(mm);
 270         kfree(umem);
 271 }
 272 EXPORT_SYMBOL(ib_umem_release);
 273
 274 int ib_umem_page_count(struct ib_umem *umem)
 275 {
 276         struct ib_umem_chunk *chunk;
 277         int shift;
 278         int i;
 279         int n;
 280
 281         shift = ilog2(umem->page_size);
 282
 283         n = 0;
 284         list_for_each_entry(chunk, &umem->chunk_list, list)
 285                 for (i = 0; i < chunk->nmap; ++i)
 286                         n += sg_dma_len(&chunk->page_list[i]) >> shift;
 287
 288         return n;
 289 }
 290 EXPORT_SYMBOL(ib_umem_page_count);