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
  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
  46 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
  47 {
  48         struct scatterlist *sg;
  49         struct page *page;
  50         int i;
  51
  52         if (umem->nmap > 0)
  53                 ib_dma_unmap_sg(dev, umem->sg_head.sgl,
  54                                 umem->nmap,
  55                                 DMA_BIDIRECTIONAL);
  56
  57         for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
  58
  59                 page = sg_page(sg);
  60                 if (umem->writable && dirty)
  61                         set_page_dirty_lock(page);
  62                 put_page(page);
  63         }
  64
  65         sg_free_table(&umem->sg_head);
  66         return;
  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         unsigned long locked;
  85         unsigned long lock_limit;
  86         unsigned long cur_base;
  87         unsigned long npages;
  88         int ret;
  89         int i;
  90         DEFINE_DMA_ATTRS(attrs);
  91         struct scatterlist *sg, *sg_list_start;
  92         int need_release = 0;
  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 = kzalloc(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         page_list = (struct page **) __get_free_page(GFP_KERNEL);
 121         if (!page_list) {
 122                 kfree(umem);
 123                 return ERR_PTR(-ENOMEM);
 124         }
 125
 126         /*
 127          * if we can't alloc the vma_list, it's not so bad;
 128          * just assume the memory is not hugetlb memory
 129          */
 130         vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
 131         if (!vma_list)
 132                 umem->hugetlb = 0;
 133
 134         npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT;
 135
 136         down_write(&current->mm->mmap_sem);
 137
 138         locked     = npages + current->mm->pinned_vm;
 139         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 140
 141         if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
 142                 ret = -ENOMEM;
 143                 goto out;
 144         }
 145
 146         cur_base = addr & PAGE_MASK;
 147
 148         if (npages == 0) {
 149                 ret = -EINVAL;
 150                 goto out;
 151         }
 152
 153         ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
 154         if (ret)
 155                 goto out;
 156
 157         need_release = 1;
 158         sg_list_start = umem->sg_head.sgl;
 159
 160         while (npages) {
 161                 ret = get_user_pages(current, current->mm, cur_base,
 162                                      min_t(unsigned long, npages,
 163                                            PAGE_SIZE / sizeof (struct page *)),
 164                                      1, !umem->writable, page_list, vma_list);
 165
 166                 if (ret < 0)
 167                         goto out;
 168
 169                 umem->npages += ret;
 170                 cur_base += ret * PAGE_SIZE;
 171                 npages   -= ret;
 172
 173                 for_each_sg(sg_list_start, sg, ret, i) {
 174                         if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
 175                                 umem->hugetlb = 0;
 176
 177                         sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
 178                 }
 179
 180                 /* preparing for next loop */
 181                 sg_list_start = sg;
 182         }
 183
 184         umem->nmap = ib_dma_map_sg_attrs(context->device,
 185                                   umem->sg_head.sgl,
 186                                   umem->npages,
 187                                   DMA_BIDIRECTIONAL,
 188                                   &attrs);
 189
 190         if (umem->nmap <= 0) {
 191                 ret = -ENOMEM;
 192                 goto out;
 193         }
 194
 195         ret = 0;
 196
 197 out:
 198         if (ret < 0) {
 199                 if (need_release)
 200                         __ib_umem_release(context->device, umem, 0);
 201                 kfree(umem);
 202         } else
 203                 current->mm->pinned_vm = locked;
 204
 205         up_write(&current->mm->mmap_sem);
 206         if (vma_list)
 207                 free_page((unsigned long) vma_list);
 208         free_page((unsigned long) page_list);
 209
 210         return ret < 0 ? ERR_PTR(ret) : umem;
 211 }
 212 EXPORT_SYMBOL(ib_umem_get);
 213
 214 static void ib_umem_account(struct work_struct *work)
 215 {
 216         struct ib_umem *umem = container_of(work, struct ib_umem, work);
 217
 218         down_write(&umem->mm->mmap_sem);
 219         umem->mm->pinned_vm -= umem->diff;
 220         up_write(&umem->mm->mmap_sem);
 221         mmput(umem->mm);
 222         kfree(umem);
 223 }
 224
 225 /**
 226  * ib_umem_release - release memory pinned with ib_umem_get
 227  * @umem: umem struct to release
 228  */
 229 void ib_umem_release(struct ib_umem *umem)
 230 {
 231         struct ib_ucontext *context = umem->context;
 232         struct mm_struct *mm;
 233         unsigned long diff;
 234
 235         __ib_umem_release(umem->context->device, umem, 1);
 236
 237         mm = get_task_mm(current);
 238         if (!mm) {
 239                 kfree(umem);
 240                 return;
 241         }
 242
 243         diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
 244
 245         /*
 246          * We may be called with the mm's mmap_sem already held.  This
 247          * can happen when a userspace munmap() is the call that drops
 248          * the last reference to our file and calls our release
 249          * method.  If there are memory regions to destroy, we'll end
 250          * up here and not be able to take the mmap_sem.  In that case
 251          * we defer the vm_locked accounting to the system workqueue.
 252          */
 253         if (context->closing) {
 254                 if (!down_write_trylock(&mm->mmap_sem)) {
 255                         INIT_WORK(&umem->work, ib_umem_account);
 256                         umem->mm   = mm;
 257                         umem->diff = diff;
 258
 259                         queue_work(ib_wq, &umem->work);
 260                         return;
 261                 }
 262         } else
 263                 down_write(&mm->mmap_sem);
 264
 265         current->mm->pinned_vm -= diff;
 266         up_write(&mm->mmap_sem);
 267         mmput(mm);
 268         kfree(umem);
 269 }
 270 EXPORT_SYMBOL(ib_umem_release);
 271
 272 int ib_umem_page_count(struct ib_umem *umem)
 273 {
 274         int shift;
 275         int i;
 276         int n;
 277         struct scatterlist *sg;
 278
 279         shift = ilog2(umem->page_size);
 280
 281         n = 0;
 282         for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
 283                 n += sg_dma_len(sg) >> shift;
 284
 285         return n;
 286 }
 287 EXPORT_SYMBOL(ib_umem_page_count);