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