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
  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(&current->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         ret = 0;
 125         while (npages) {
 126                 ret = get_user_pages(current, current->mm, cur_base,
 127                                      min_t(int, npages,
 128                                            PAGE_SIZE / sizeof (struct page *)),
 129                                      1, !umem->writable, page_list, NULL);
 130
 131                 if (ret < 0)
 132                         goto out;
 133
 134                 cur_base += ret * PAGE_SIZE;
 135                 npages   -= ret;
 136
 137                 off = 0;
 138
 139                 while (ret) {
 140                         chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) *
 141                                         min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK),
 142                                         GFP_KERNEL);
 143                         if (!chunk) {
 144                                 ret = -ENOMEM;
 145                                 goto out;
 146                         }
 147
 148                         chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK);
 149                         for (i = 0; i < chunk->nents; ++i) {
 150                                 chunk->page_list[i].page   = page_list[i + off];
 151                                 chunk->page_list[i].offset = 0;
 152                                 chunk->page_list[i].length = PAGE_SIZE;
 153                         }
 154
 155                         chunk->nmap = ib_dma_map_sg(context->device,
 156                                                     &chunk->page_list[0],
 157                                                     chunk->nents,
 158                                                     DMA_BIDIRECTIONAL);
 159                         if (chunk->nmap <= 0) {
 160                                 for (i = 0; i < chunk->nents; ++i)
 161                                         put_page(chunk->page_list[i].page);
 162                                 kfree(chunk);
 163
 164                                 ret = -ENOMEM;
 165                                 goto out;
 166                         }
 167
 168                         ret -= chunk->nents;
 169                         off += chunk->nents;
 170                         list_add_tail(&chunk->list, &umem->chunk_list);
 171                 }
 172
 173                 ret = 0;
 174         }
 175
 176 out:
 177         if (ret < 0) {
 178                 __ib_umem_release(context->device, umem, 0);
 179                 kfree(umem);
 180         } else
 181                 current->mm->locked_vm = locked;
 182
 183         up_write(&current->mm->mmap_sem);
 184         free_page((unsigned long) page_list);
 185
 186         return ret < 0 ? ERR_PTR(ret) : umem;
 187 }
 188 EXPORT_SYMBOL(ib_umem_get);
 189
 190 static void ib_umem_account(struct work_struct *work)
 191 {
 192         struct ib_umem *umem = container_of(work, struct ib_umem, work);
 193
 194         down_write(&umem->mm->mmap_sem);
 195         umem->mm->locked_vm -= umem->diff;
 196         up_write(&umem->mm->mmap_sem);
 197         mmput(umem->mm);
 198         kfree(umem);
 199 }
 200
 201 /**
 202  * ib_umem_release - release memory pinned with ib_umem_get
 203  * @umem: umem struct to release
 204  */
 205 void ib_umem_release(struct ib_umem *umem)
 206 {
 207         struct ib_ucontext *context = umem->context;
 208         struct mm_struct *mm;
 209         unsigned long diff;
 210
 211         __ib_umem_release(umem->context->device, umem, 1);
 212
 213         mm = get_task_mm(current);
 214         if (!mm) {
 215                 kfree(umem);
 216                 return;
 217         }
 218
 219         diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
 220
 221         /*
 222          * We may be called with the mm's mmap_sem already held.  This
 223          * can happen when a userspace munmap() is the call that drops
 224          * the last reference to our file and calls our release
 225          * method.  If there are memory regions to destroy, we'll end
 226          * up here and not be able to take the mmap_sem.  In that case
 227          * we defer the vm_locked accounting to the system workqueue.
 228          */
 229         if (context->closing) {
 230                 if (!down_write_trylock(&mm->mmap_sem)) {
 231                         INIT_WORK(&umem->work, ib_umem_account);
 232                         umem->mm   = mm;
 233                         umem->diff = diff;
 234
 235                         schedule_work(&umem->work);
 236                         return;
 237                 }
 238         } else
 239                 down_write(&mm->mmap_sem);
 240
 241         current->mm->locked_vm -= diff;
 242         up_write(&mm->mmap_sem);
 243         mmput(mm);
 244         kfree(umem);
 245 }
 246 EXPORT_SYMBOL(ib_umem_release);
 247
 248 int ib_umem_page_count(struct ib_umem *umem)
 249 {
 250         struct ib_umem_chunk *chunk;
 251         int shift;
 252         int i;
 253         int n;
 254
 255         shift = ilog2(umem->page_size);
 256
 257         n = 0;
 258         list_for_each_entry(chunk, &umem->chunk_list, list)
 259                 for (i = 0; i < chunk->nmap; ++i)
 260                         n += sg_dma_len(&chunk->page_list[i]) >> shift;
 261
 262         return n;
 263 }
 264 EXPORT_SYMBOL(ib_umem_page_count);