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/hugetlb.h>
  39 #include <linux/dma-attrs.h>
  40
  41 #include "uverbs.h"
  42
  43 #define IB_UMEM_MAX_PAGE_CHUNK                                          \
  44         ((PAGE_SIZE - offsetof(struct ib_umem_chunk, page_list)) /      \
  45          ((void *) &((struct ib_umem_chunk *) 0)->page_list[1] -        \
  46           (void *) &((struct ib_umem_chunk *) 0)->page_list[0]))
  47
  48 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
  49 {
  50         struct ib_umem_chunk *chunk, *tmp;
  51         int i;
  52
  53         list_for_each_entry_safe(chunk, tmp, &umem->chunk_list, list) {
  54                 ib_dma_unmap_sg(dev, chunk->page_list,
  55                                 chunk->nents, DMA_BIDIRECTIONAL);
  56                 for (i = 0; i < chunk->nents; ++i) {
  57                         struct page *page = sg_page(&chunk->page_list[i]);
  58
  59                         if (umem->writable && dirty)
  60                                 set_page_dirty_lock(page);
  61                         put_page(page);
  62                 }
  63
  64                 kfree(chunk);
  65         }
  66 }
  67
  68 /**
  69  * ib_umem_get - Pin and DMA map userspace memory.
  70  * @context: userspace context to pin memory for
  71  * @addr: userspace virtual address to start at
  72  * @size: length of region to pin
  73  * @access: IB_ACCESS_xxx flags for memory being pinned
  74  * @dmasync: flush in-flight DMA when the memory region is written
  75  */
  76 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
  77                             size_t size, int access, int dmasync)
  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         DEFINE_DMA_ATTRS(attrs);
  91
  92         if (dmasync)
  93                 dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
  94
  95         if (!can_do_mlock())
  96                 return ERR_PTR(-EPERM);
  97
  98         umem = kmalloc(sizeof *umem, GFP_KERNEL);
  99         if (!umem)
 100                 return ERR_PTR(-ENOMEM);
 101
 102         umem->context   = context;
 103         umem->length    = size;
 104         umem->offset    = addr & ~PAGE_MASK;
 105         umem->page_size = PAGE_SIZE;
 106         /*
 107          * We ask for writable memory if any access flags other than
 108          * "remote read" are set.  "Local write" and "remote write"
 109          * obviously require write access.  "Remote atomic" can do
 110          * things like fetch and add, which will modify memory, and
 111          * "MW bind" can change permissions by binding a window.
 112          */
 113         umem->writable  = !!(access & ~IB_ACCESS_REMOTE_READ);
 114
 115         /* We assume the memory is from hugetlb until proved otherwise */
 116         umem->hugetlb   = 1;
 117
 118         INIT_LIST_HEAD(&umem->chunk_list);
 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->locked_vm;
 139         lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> 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         ret = 0;
 149         while (npages) {
 150                 ret = get_user_pages(current, current->mm, cur_base,
 151                                      min_t(unsigned long, npages,
 152                                            PAGE_SIZE / sizeof (struct page *)),
 153                                      1, !umem->writable, page_list, vma_list);
 154
 155                 if (ret < 0)
 156                         goto out;
 157
 158                 cur_base += ret * PAGE_SIZE;
 159                 npages   -= ret;
 160
 161                 off = 0;
 162
 163                 while (ret) {
 164                         chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) *
 165                                         min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK),
 166                                         GFP_KERNEL);
 167                         if (!chunk) {
 168                                 ret = -ENOMEM;
 169                                 goto out;
 170                         }
 171
 172                         chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK);
 173                         sg_init_table(chunk->page_list, chunk->nents);
 174                         for (i = 0; i < chunk->nents; ++i) {
 175                                 if (vma_list &&
 176                                     !is_vm_hugetlb_page(vma_list[i + off]))
 177                                         umem->hugetlb = 0;
 178                                 sg_set_page(&chunk->page_list[i], page_list[i + off], PAGE_SIZE, 0);
 179                         }
 180
 181                         chunk->nmap = ib_dma_map_sg_attrs(context->device,
 182                                                           &chunk->page_list[0],
 183                                                           chunk->nents,
 184                                                           DMA_BIDIRECTIONAL,
 185                                                           &attrs);
 186                         if (chunk->nmap <= 0) {
 187                                 for (i = 0; i < chunk->nents; ++i)
 188                                         put_page(sg_page(&chunk->page_list[i]));
 189                                 kfree(chunk);
 190
 191                                 ret = -ENOMEM;
 192                                 goto out;
 193                         }
 194
 195                         ret -= chunk->nents;
 196                         off += chunk->nents;
 197                         list_add_tail(&chunk->list, &umem->chunk_list);
 198                 }
 199
 200                 ret = 0;
 201         }
 202
 203 out:
 204         if (ret < 0) {
 205                 __ib_umem_release(context->device, umem, 0);
 206                 kfree(umem);
 207         } else
 208                 current->mm->locked_vm = locked;
 209
 210         up_write(&current->mm->mmap_sem);
 211         if (vma_list)
 212                 free_page((unsigned long) vma_list);
 213         free_page((unsigned long) page_list);
 214
 215         return ret < 0 ? ERR_PTR(ret) : umem;
 216 }
 217 EXPORT_SYMBOL(ib_umem_get);
 218
 219 static void ib_umem_account(struct work_struct *work)
 220 {
 221         struct ib_umem *umem = container_of(work, struct ib_umem, work);
 222
 223         down_write(&umem->mm->mmap_sem);
 224         umem->mm->locked_vm -= umem->diff;
 225         up_write(&umem->mm->mmap_sem);
 226         mmput(umem->mm);
 227         kfree(umem);
 228 }
 229
 230 /**
 231  * ib_umem_release - release memory pinned with ib_umem_get
 232  * @umem: umem struct to release
 233  */
 234 void ib_umem_release(struct ib_umem *umem)
 235 {
 236         struct ib_ucontext *context = umem->context;
 237         struct mm_struct *mm;
 238         unsigned long diff;
 239
 240         __ib_umem_release(umem->context->device, umem, 1);
 241
 242         mm = get_task_mm(current);
 243         if (!mm) {
 244                 kfree(umem);
 245                 return;
 246         }
 247
 248         diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
 249
 250         /*
 251          * We may be called with the mm's mmap_sem already held.  This
 252          * can happen when a userspace munmap() is the call that drops
 253          * the last reference to our file and calls our release
 254          * method.  If there are memory regions to destroy, we'll end
 255          * up here and not be able to take the mmap_sem.  In that case
 256          * we defer the vm_locked accounting to the system workqueue.
 257          */
 258         if (context->closing) {
 259                 if (!down_write_trylock(&mm->mmap_sem)) {
 260                         INIT_WORK(&umem->work, ib_umem_account);
 261                         umem->mm   = mm;
 262                         umem->diff = diff;
 263
 264                         schedule_work(&umem->work);
 265                         return;
 266                 }
 267         } else
 268                 down_write(&mm->mmap_sem);
 269
 270         current->mm->locked_vm -= diff;
 271         up_write(&mm->mmap_sem);
 272         mmput(mm);
 273         kfree(umem);
 274 }
 275 EXPORT_SYMBOL(ib_umem_release);
 276
 277 int ib_umem_page_count(struct ib_umem *umem)
 278 {
 279         struct ib_umem_chunk *chunk;
 280         int shift;
 281         int i;
 282         int n;
 283
 284         shift = ilog2(umem->page_size);
 285
 286         n = 0;
 287         list_for_each_entry(chunk, &umem->chunk_list, list)
 288                 for (i = 0; i < chunk->nmap; ++i)
 289                         n += sg_dma_len(&chunk->page_list[i]) >> shift;
 290
 291         return n;
 292 }
 293 EXPORT_SYMBOL(ib_umem_page_count);