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