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