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 #include <rdma/ib_umem_odp.h>
  43
  44 #include "uverbs.h"
  45
  46
  47 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
  48 {
  49         struct scatterlist *sg;
  50         struct page *page;
  51         int i;
  52
  53         if (umem->nmap > 0)
  54                 ib_dma_unmap_sg(dev, umem->sg_head.sgl,
  55                                 umem->nmap,
  56                                 DMA_BIDIRECTIONAL);
  57
  58         for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
  59
  60                 page = sg_page(sg);
  61                 if (umem->writable && dirty)
  62                         set_page_dirty_lock(page);
  63                 put_page(page);
  64         }
  65
  66         sg_free_table(&umem->sg_head);
  67         return;
  68
  69 }
  70
  71 /**
  72  * ib_umem_get - Pin and DMA map userspace memory.
  73  *
  74  * If access flags indicate ODP memory, avoid pinning. Instead, stores
  75  * the mm for future page fault handling in conjunction with MMU notifiers.
  76  *
  77  * @context: userspace context to pin memory for
  78  * @addr: userspace virtual address to start at
  79  * @size: length of region to pin
  80  * @access: IB_ACCESS_xxx flags for memory being pinned
  81  * @dmasync: flush in-flight DMA when the memory region is written
  82  */
  83 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
  84                             size_t size, int access, int dmasync)
  85 {
  86         struct ib_umem *umem;
  87         struct page **page_list;
  88         struct vm_area_struct **vma_list;
  89         unsigned long locked;
  90         unsigned long lock_limit;
  91         unsigned long cur_base;
  92         unsigned long npages;
  93         int ret;
  94         int i;
  95         DEFINE_DMA_ATTRS(attrs);
  96         struct scatterlist *sg, *sg_list_start;
  97         int need_release = 0;
  98
  99         if (dmasync)
 100                 dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
 101
 102         if (!size)
 103                 return ERR_PTR(-EINVAL);
 104
 105         /*
 106          * If the combination of the addr and size requested for this memory
 107          * region causes an integer overflow, return error.
 108          */
 109         if (((addr + size) < addr) ||
 110             PAGE_ALIGN(addr + size) < (addr + size))
 111                 return ERR_PTR(-EINVAL);
 112
 113         if (!can_do_mlock())
 114                 return ERR_PTR(-EPERM);
 115
 116         umem = kzalloc(sizeof *umem, GFP_KERNEL);
 117         if (!umem)
 118                 return ERR_PTR(-ENOMEM);
 119
 120         umem->context   = context;
 121         umem->length    = size;
 122         umem->address   = addr;
 123         umem->page_size = PAGE_SIZE;
 124         umem->pid       = get_task_pid(current, PIDTYPE_PID);
 125         /*
 126          * We ask for writable memory if any of the following
 127          * access flags are set.  "Local write" and "remote write"
 128          * obviously require write access.  "Remote atomic" can do
 129          * things like fetch and add, which will modify memory, and
 130          * "MW bind" can change permissions by binding a window.
 131          */
 132         umem->writable  = !!(access &
 133                 (IB_ACCESS_LOCAL_WRITE   | IB_ACCESS_REMOTE_WRITE |
 134                  IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
 135
 136         if (access & IB_ACCESS_ON_DEMAND) {
 137                 ret = ib_umem_odp_get(context, umem);
 138                 if (ret) {
 139                         kfree(umem);
 140                         return ERR_PTR(ret);
 141                 }
 142                 return umem;
 143         }
 144
 145         umem->odp_data = NULL;
 146
 147         /* We assume the memory is from hugetlb until proved otherwise */
 148         umem->hugetlb   = 1;
 149
 150         page_list = (struct page **) __get_free_page(GFP_KERNEL);
 151         if (!page_list) {
 152                 kfree(umem);
 153                 return ERR_PTR(-ENOMEM);
 154         }
 155
 156         /*
 157          * if we can't alloc the vma_list, it's not so bad;
 158          * just assume the memory is not hugetlb memory
 159          */
 160         vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
 161         if (!vma_list)
 162                 umem->hugetlb = 0;
 163
 164         npages = ib_umem_num_pages(umem);
 165
 166         down_write(&current->mm->mmap_sem);
 167
 168         locked     = npages + current->mm->pinned_vm;
 169         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 170
 171         if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
 172                 ret = -ENOMEM;
 173                 goto out;
 174         }
 175
 176         cur_base = addr & PAGE_MASK;
 177
 178         if (npages == 0) {
 179                 ret = -EINVAL;
 180                 goto out;
 181         }
 182
 183         ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
 184         if (ret)
 185                 goto out;
 186
 187         need_release = 1;
 188         sg_list_start = umem->sg_head.sgl;
 189
 190         while (npages) {
 191                 ret = get_user_pages(current, current->mm, cur_base,
 192                                      min_t(unsigned long, npages,
 193                                            PAGE_SIZE / sizeof (struct page *)),
 194                                      1, !umem->writable, page_list, vma_list);
 195
 196                 if (ret < 0)
 197                         goto out;
 198
 199                 umem->npages += ret;
 200                 cur_base += ret * PAGE_SIZE;
 201                 npages   -= ret;
 202
 203                 for_each_sg(sg_list_start, sg, ret, i) {
 204                         if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
 205                                 umem->hugetlb = 0;
 206
 207                         sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
 208                 }
 209
 210                 /* preparing for next loop */
 211                 sg_list_start = sg;
 212         }
 213
 214         umem->nmap = ib_dma_map_sg_attrs(context->device,
 215                                   umem->sg_head.sgl,
 216                                   umem->npages,
 217                                   DMA_BIDIRECTIONAL,
 218                                   &attrs);
 219
 220         if (umem->nmap <= 0) {
 221                 ret = -ENOMEM;
 222                 goto out;
 223         }
 224
 225         ret = 0;
 226
 227 out:
 228         if (ret < 0) {
 229                 if (need_release)
 230                         __ib_umem_release(context->device, umem, 0);
 231                 put_pid(umem->pid);
 232                 kfree(umem);
 233         } else
 234                 current->mm->pinned_vm = locked;
 235
 236         up_write(&current->mm->mmap_sem);
 237         if (vma_list)
 238                 free_page((unsigned long) vma_list);
 239         free_page((unsigned long) page_list);
 240
 241         return ret < 0 ? ERR_PTR(ret) : umem;
 242 }
 243 EXPORT_SYMBOL(ib_umem_get);
 244
 245 static void ib_umem_account(struct work_struct *work)
 246 {
 247         struct ib_umem *umem = container_of(work, struct ib_umem, work);
 248
 249         down_write(&umem->mm->mmap_sem);
 250         umem->mm->pinned_vm -= umem->diff;
 251         up_write(&umem->mm->mmap_sem);
 252         mmput(umem->mm);
 253         kfree(umem);
 254 }
 255
 256 /**
 257  * ib_umem_release - release memory pinned with ib_umem_get
 258  * @umem: umem struct to release
 259  */
 260 void ib_umem_release(struct ib_umem *umem)
 261 {
 262         struct ib_ucontext *context = umem->context;
 263         struct mm_struct *mm;
 264         struct task_struct *task;
 265         unsigned long diff;
 266
 267         if (umem->odp_data) {
 268                 ib_umem_odp_release(umem);
 269                 return;
 270         }
 271
 272         __ib_umem_release(umem->context->device, umem, 1);
 273
 274         task = get_pid_task(umem->pid, PIDTYPE_PID);
 275         put_pid(umem->pid);
 276         if (!task)
 277                 goto out;
 278         mm = get_task_mm(task);
 279         put_task_struct(task);
 280         if (!mm)
 281                 goto out;
 282
 283         diff = ib_umem_num_pages(umem);
 284
 285         /*
 286          * We may be called with the mm's mmap_sem already held.  This
 287          * can happen when a userspace munmap() is the call that drops
 288          * the last reference to our file and calls our release
 289          * method.  If there are memory regions to destroy, we'll end
 290          * up here and not be able to take the mmap_sem.  In that case
 291          * we defer the vm_locked accounting to the system workqueue.
 292          */
 293         if (context->closing) {
 294                 if (!down_write_trylock(&mm->mmap_sem)) {
 295                         INIT_WORK(&umem->work, ib_umem_account);
 296                         umem->mm   = mm;
 297                         umem->diff = diff;
 298
 299                         queue_work(ib_wq, &umem->work);
 300                         return;
 301                 }
 302         } else
 303                 down_write(&mm->mmap_sem);
 304
 305         mm->pinned_vm -= diff;
 306         up_write(&mm->mmap_sem);
 307         mmput(mm);
 308 out:
 309         kfree(umem);
 310 }
 311 EXPORT_SYMBOL(ib_umem_release);
 312
 313 int ib_umem_page_count(struct ib_umem *umem)
 314 {
 315         int shift;
 316         int i;
 317         int n;
 318         struct scatterlist *sg;
 319
 320         if (umem->odp_data)
 321                 return ib_umem_num_pages(umem);
 322
 323         shift = ilog2(umem->page_size);
 324
 325         n = 0;
 326         for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
 327                 n += sg_dma_len(sg) >> shift;
 328
 329         return n;
 330 }
 331 EXPORT_SYMBOL(ib_umem_page_count);
 332
 333 /*
 334  * Copy from the given ib_umem's pages to the given buffer.
 335  *
 336  * umem - the umem to copy from
 337  * offset - offset to start copying from
 338  * dst - destination buffer
 339  * length - buffer length
 340  *
 341  * Returns 0 on success, or an error code.
 342  */
 343 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
 344                       size_t length)
 345 {
 346         size_t end = offset + length;
 347         int ret;
 348
 349         if (offset > umem->length || length > umem->length - offset) {
 350                 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n",
 351                        offset, umem->length, end);
 352                 return -EINVAL;
 353         }
 354
 355         ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length,
 356                                  offset + ib_umem_offset(umem));
 357
 358         if (ret < 0)
 359                 return ret;
 360         else if (ret != length)
 361                 return -EINVAL;
 362         else
 363                 return 0;
 364 }
 365 EXPORT_SYMBOL(ib_umem_copy_from);