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/slab.h>
  41 #include <rdma/ib_umem_odp.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->npages,
  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  *
  73  * If access flags indicate ODP memory, avoid pinning. Instead, stores
  74  * the mm for future page fault handling in conjunction with MMU notifiers.
  75  *
  76  * @context: userspace context to pin memory for
  77  * @addr: userspace virtual address to start at
  78  * @size: length of region to pin
  79  * @access: IB_ACCESS_xxx flags for memory being pinned
  80  * @dmasync: flush in-flight DMA when the memory region is written
  81  */
  82 struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
  83                             size_t size, int access, int dmasync)
  84 {
  85         struct ib_umem *umem;
  86         struct page **page_list;
  87         struct vm_area_struct **vma_list;
  88         unsigned long locked;
  89         unsigned long lock_limit;
  90         unsigned long cur_base;
  91         unsigned long npages;
  92         int ret;
  93         int i;
  94         unsigned long dma_attrs = 0;
  95         struct scatterlist *sg, *sg_list_start;
  96         int need_release = 0;
  97         unsigned int gup_flags = FOLL_WRITE;
  98
  99         if (dmasync)
 100                 dma_attrs |= DMA_ATTR_WRITE_BARRIER;
 101
 102         /*
 103          * If the combination of the addr and size requested for this memory
 104          * region causes an integer overflow, return error.
 105          */
 106         if (((addr + size) < addr) ||
 107             PAGE_ALIGN(addr + size) < (addr + size))
 108                 return ERR_PTR(-EINVAL);
 109
 110         if (!can_do_mlock())
 111                 return ERR_PTR(-EPERM);
 112
 113         umem = kzalloc(sizeof *umem, GFP_KERNEL);
 114         if (!umem)
 115                 return ERR_PTR(-ENOMEM);
 116
 117         umem->context   = context;
 118         umem->length    = size;
 119         umem->address   = addr;
 120         umem->page_size = PAGE_SIZE;
 121         umem->pid       = get_task_pid(current, PIDTYPE_PID);
 122         /*
 123          * We ask for writable memory if any of the following
 124          * access flags are set.  "Local write" and "remote write"
 125          * obviously require write access.  "Remote atomic" can do
 126          * things like fetch and add, which will modify memory, and
 127          * "MW bind" can change permissions by binding a window.
 128          */
 129         umem->writable  = !!(access &
 130                 (IB_ACCESS_LOCAL_WRITE   | IB_ACCESS_REMOTE_WRITE |
 131                  IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
 132
 133         if (access & IB_ACCESS_ON_DEMAND) {
 134                 put_pid(umem->pid);
 135                 ret = ib_umem_odp_get(context, umem);
 136                 if (ret) {
 137                         kfree(umem);
 138                         return ERR_PTR(ret);
 139                 }
 140                 return umem;
 141         }
 142
 143         umem->odp_data = NULL;
 144
 145         /* We assume the memory is from hugetlb until proved otherwise */
 146         umem->hugetlb   = 1;
 147
 148         page_list = (struct page **) __get_free_page(GFP_KERNEL);
 149         if (!page_list) {
 150                 put_pid(umem->pid);
 151                 kfree(umem);
 152                 return ERR_PTR(-ENOMEM);
 153         }
 154
 155         /*
 156          * if we can't alloc the vma_list, it's not so bad;
 157          * just assume the memory is not hugetlb memory
 158          */
 159         vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
 160         if (!vma_list)
 161                 umem->hugetlb = 0;
 162
 163         npages = ib_umem_num_pages(umem);
 164
 165         down_write(&current->mm->mmap_sem);
 166
 167         locked     = npages + current->mm->pinned_vm;
 168         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 169
 170         if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
 171                 ret = -ENOMEM;
 172                 goto out;
 173         }
 174
 175         cur_base = addr & PAGE_MASK;
 176
 177         if (npages == 0 || npages > UINT_MAX) {
 178                 ret = -EINVAL;
 179                 goto out;
 180         }
 181
 182         ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
 183         if (ret)
 184                 goto out;
 185
 186         if (!umem->writable)
 187                 gup_flags |= FOLL_FORCE;
 188
 189         need_release = 1;
 190         sg_list_start = umem->sg_head.sgl;
 191
 192         while (npages) {
 193                 ret = get_user_pages(cur_base,
 194                                      min_t(unsigned long, npages,
 195                                            PAGE_SIZE / sizeof (struct page *)),
 196                                      gup_flags, page_list, vma_list);
 197
 198                 if (ret < 0)
 199                         goto out;
 200
 201                 umem->npages += ret;
 202                 cur_base += ret * PAGE_SIZE;
 203                 npages   -= ret;
 204
 205                 for_each_sg(sg_list_start, sg, ret, i) {
 206                         if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
 207                                 umem->hugetlb = 0;
 208
 209                         sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
 210                 }
 211
 212                 /* preparing for next loop */
 213                 sg_list_start = sg;
 214         }
 215
 216         umem->nmap = ib_dma_map_sg_attrs(context->device,
 217                                   umem->sg_head.sgl,
 218                                   umem->npages,
 219                                   DMA_BIDIRECTIONAL,
 220                                   dma_attrs);
 221
 222         if (umem->nmap <= 0) {
 223                 ret = -ENOMEM;
 224                 goto out;
 225         }
 226
 227         ret = 0;
 228
 229 out:
 230         if (ret < 0) {
 231                 if (need_release)
 232                         __ib_umem_release(context->device, umem, 0);
 233                 put_pid(umem->pid);
 234                 kfree(umem);
 235         } else
 236                 current->mm->pinned_vm = locked;
 237
 238         up_write(&current->mm->mmap_sem);
 239         if (vma_list)
 240                 free_page((unsigned long) vma_list);
 241         free_page((unsigned long) page_list);
 242
 243         return ret < 0 ? ERR_PTR(ret) : umem;
 244 }
 245 EXPORT_SYMBOL(ib_umem_get);
 246
 247 static void ib_umem_account(struct work_struct *work)
 248 {
 249         struct ib_umem *umem = container_of(work, struct ib_umem, work);
 250
 251         down_write(&umem->mm->mmap_sem);
 252         umem->mm->pinned_vm -= umem->diff;
 253         up_write(&umem->mm->mmap_sem);
 254         mmput(umem->mm);
 255         kfree(umem);
 256 }
 257
 258 /**
 259  * ib_umem_release - release memory pinned with ib_umem_get
 260  * @umem: umem struct to release
 261  */
 262 void ib_umem_release(struct ib_umem *umem)
 263 {
 264         struct ib_ucontext *context = umem->context;
 265         struct mm_struct *mm;
 266         struct task_struct *task;
 267         unsigned long diff;
 268
 269         if (umem->odp_data) {
 270                 ib_umem_odp_release(umem);
 271                 return;
 272         }
 273
 274         __ib_umem_release(umem->context->device, umem, 1);
 275
 276         task = get_pid_task(umem->pid, PIDTYPE_PID);
 277         put_pid(umem->pid);
 278         if (!task)
 279                 goto out;
 280         mm = get_task_mm(task);
 281         put_task_struct(task);
 282         if (!mm)
 283                 goto out;
 284
 285         diff = ib_umem_num_pages(umem);
 286
 287         /*
 288          * We may be called with the mm's mmap_sem already held.  This
 289          * can happen when a userspace munmap() is the call that drops
 290          * the last reference to our file and calls our release
 291          * method.  If there are memory regions to destroy, we'll end
 292          * up here and not be able to take the mmap_sem.  In that case
 293          * we defer the vm_locked accounting to the system workqueue.
 294          */
 295         if (context->closing) {
 296                 if (!down_write_trylock(&mm->mmap_sem)) {
 297                         INIT_WORK(&umem->work, ib_umem_account);
 298                         umem->mm   = mm;
 299                         umem->diff = diff;
 300
 301                         queue_work(ib_wq, &umem->work);
 302                         return;
 303                 }
 304         } else
 305                 down_write(&mm->mmap_sem);
 306
 307         mm->pinned_vm -= diff;
 308         up_write(&mm->mmap_sem);
 309         mmput(mm);
 310 out:
 311         kfree(umem);
 312 }
 313 EXPORT_SYMBOL(ib_umem_release);
 314
 315 int ib_umem_page_count(struct ib_umem *umem)
 316 {
 317         int shift;
 318         int i;
 319         int n;
 320         struct scatterlist *sg;
 321
 322         if (umem->odp_data)
 323                 return ib_umem_num_pages(umem);
 324
 325         shift = ilog2(umem->page_size);
 326
 327         n = 0;
 328         for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
 329                 n += sg_dma_len(sg) >> shift;
 330
 331         return n;
 332 }
 333 EXPORT_SYMBOL(ib_umem_page_count);
 334
 335 /*
 336  * Copy from the given ib_umem's pages to the given buffer.
 337  *
 338  * umem - the umem to copy from
 339  * offset - offset to start copying from
 340  * dst - destination buffer
 341  * length - buffer length
 342  *
 343  * Returns 0 on success, or an error code.
 344  */
 345 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
 346                       size_t length)
 347 {
 348         size_t end = offset + length;
 349         int ret;
 350
 351         if (offset > umem->length || length > umem->length - offset) {
 352                 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n",
 353                        offset, umem->length, end);
 354                 return -EINVAL;
 355         }
 356
 357         ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length,
 358                                  offset + ib_umem_offset(umem));
 359
 360         if (ret < 0)
 361                 return ret;
 362         else if (ret != length)
 363                 return -EINVAL;
 364         else
 365                 return 0;
 366 }
 367 EXPORT_SYMBOL(ib_umem_copy_from);