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/signal.h>
  38 #include <linux/sched/mm.h>
  39 #include <linux/export.h>
  40 #include <linux/hugetlb.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->npages,
  56                                 DMA_BIDIRECTIONAL);
  57
  58         for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
  59
  60                 page = sg_page(sg);
  61                 if (!PageDirty(page) && 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         unsigned long dma_attrs = 0;
  96         struct scatterlist *sg, *sg_list_start;
  97         int need_release = 0;
  98         unsigned int gup_flags = FOLL_WRITE;
  99
 100         if (dmasync)
 101                 dma_attrs |= DMA_ATTR_WRITE_BARRIER;
 102
 103         /*
 104          * If the combination of the addr and size requested for this memory
 105          * region causes an integer overflow, return error.
 106          */
 107         if (((addr + size) < addr) ||
 108             PAGE_ALIGN(addr + size) < (addr + size))
 109                 return ERR_PTR(-EINVAL);
 110
 111         if (!can_do_mlock())
 112                 return ERR_PTR(-EPERM);
 113
 114         umem = kzalloc(sizeof *umem, GFP_KERNEL);
 115         if (!umem)
 116                 return ERR_PTR(-ENOMEM);
 117
 118         umem->context    = context;
 119         umem->length     = size;
 120         umem->address    = addr;
 121         umem->page_shift = PAGE_SHIFT;
 122         umem->pid        = get_task_pid(current, PIDTYPE_PID);
 123         /*
 124          * We ask for writable memory if any of the following
 125          * access flags are set.  "Local write" and "remote write"
 126          * obviously require write access.  "Remote atomic" can do
 127          * things like fetch and add, which will modify memory, and
 128          * "MW bind" can change permissions by binding a window.
 129          */
 130         umem->writable  = !!(access &
 131                 (IB_ACCESS_LOCAL_WRITE   | IB_ACCESS_REMOTE_WRITE |
 132                  IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
 133
 134         if (access & IB_ACCESS_ON_DEMAND) {
 135                 put_pid(umem->pid);
 136                 ret = ib_umem_odp_get(context, umem, access);
 137                 if (ret) {
 138                         kfree(umem);
 139                         return ERR_PTR(ret);
 140                 }
 141                 return umem;
 142         }
 143
 144         umem->odp_data = NULL;
 145
 146         /* We assume the memory is from hugetlb until proved otherwise */
 147         umem->hugetlb   = 1;
 148
 149         page_list = (struct page **) __get_free_page(GFP_KERNEL);
 150         if (!page_list) {
 151                 put_pid(umem->pid);
 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 || npages > UINT_MAX) {
 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         if (!umem->writable)
 188                 gup_flags |= FOLL_FORCE;
 189
 190         need_release = 1;
 191         sg_list_start = umem->sg_head.sgl;
 192
 193         while (npages) {
 194                 ret = get_user_pages(cur_base,
 195                                      min_t(unsigned long, npages,
 196                                            PAGE_SIZE / sizeof (struct page *)),
 197                                      gup_flags, page_list, vma_list);
 198
 199                 if (ret < 0)
 200                         goto out;
 201
 202                 umem->npages += ret;
 203                 cur_base += ret * PAGE_SIZE;
 204                 npages   -= ret;
 205
 206                 for_each_sg(sg_list_start, sg, ret, i) {
 207                         if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
 208                                 umem->hugetlb = 0;
 209
 210                         sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
 211                 }
 212
 213                 /* preparing for next loop */
 214                 sg_list_start = sg;
 215         }
 216
 217         umem->nmap = ib_dma_map_sg_attrs(context->device,
 218                                   umem->sg_head.sgl,
 219                                   umem->npages,
 220                                   DMA_BIDIRECTIONAL,
 221                                   dma_attrs);
 222
 223         if (umem->nmap <= 0) {
 224                 ret = -ENOMEM;
 225                 goto out;
 226         }
 227
 228         ret = 0;
 229
 230 out:
 231         if (ret < 0) {
 232                 if (need_release)
 233                         __ib_umem_release(context->device, umem, 0);
 234                 put_pid(umem->pid);
 235                 kfree(umem);
 236         } else
 237                 current->mm->pinned_vm = locked;
 238
 239         up_write(&current->mm->mmap_sem);
 240         if (vma_list)
 241                 free_page((unsigned long) vma_list);
 242         free_page((unsigned long) page_list);
 243
 244         return ret < 0 ? ERR_PTR(ret) : umem;
 245 }
 246 EXPORT_SYMBOL(ib_umem_get);
 247
 248 static void ib_umem_account(struct work_struct *work)
 249 {
 250         struct ib_umem *umem = container_of(work, struct ib_umem, work);
 251
 252         down_write(&umem->mm->mmap_sem);
 253         umem->mm->pinned_vm -= umem->diff;
 254         up_write(&umem->mm->mmap_sem);
 255         mmput(umem->mm);
 256         kfree(umem);
 257 }
 258
 259 /**
 260  * ib_umem_release - release memory pinned with ib_umem_get
 261  * @umem: umem struct to release
 262  */
 263 void ib_umem_release(struct ib_umem *umem)
 264 {
 265         struct ib_ucontext *context = umem->context;
 266         struct mm_struct *mm;
 267         struct task_struct *task;
 268         unsigned long diff;
 269
 270         if (umem->odp_data) {
 271                 ib_umem_odp_release(umem);
 272                 return;
 273         }
 274
 275         __ib_umem_release(umem->context->device, umem, 1);
 276
 277         task = get_pid_task(umem->pid, PIDTYPE_PID);
 278         put_pid(umem->pid);
 279         if (!task)
 280                 goto out;
 281         mm = get_task_mm(task);
 282         put_task_struct(task);
 283         if (!mm)
 284                 goto out;
 285
 286         diff = ib_umem_num_pages(umem);
 287
 288         /*
 289          * We may be called with the mm's mmap_sem already held.  This
 290          * can happen when a userspace munmap() is the call that drops
 291          * the last reference to our file and calls our release
 292          * method.  If there are memory regions to destroy, we'll end
 293          * up here and not be able to take the mmap_sem.  In that case
 294          * we defer the vm_locked accounting to the system workqueue.
 295          */
 296         if (context->closing) {
 297                 if (!down_write_trylock(&mm->mmap_sem)) {
 298                         INIT_WORK(&umem->work, ib_umem_account);
 299                         umem->mm   = mm;
 300                         umem->diff = diff;
 301
 302                         queue_work(ib_wq, &umem->work);
 303                         return;
 304                 }
 305         } else
 306                 down_write(&mm->mmap_sem);
 307
 308         mm->pinned_vm -= diff;
 309         up_write(&mm->mmap_sem);
 310         mmput(mm);
 311 out:
 312         kfree(umem);
 313 }
 314 EXPORT_SYMBOL(ib_umem_release);
 315
 316 int ib_umem_page_count(struct ib_umem *umem)
 317 {
 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         n = 0;
 326         for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
 327                 n += sg_dma_len(sg) >> umem->page_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);