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         /*
 103          * If the combination of the addr and size requested for this memory
 104          * region causes an integer overflow, return error.
 105          */
 106         if ((PAGE_ALIGN(addr + size) <= size) ||
 107             (PAGE_ALIGN(addr + size) <= addr))
 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                 ret = ib_umem_odp_get(context, umem);
 135                 if (ret) {
 136                         kfree(umem);
 137                         return ERR_PTR(ret);
 138                 }
 139                 return umem;
 140         }
 141
 142         umem->odp_data = NULL;
 143
 144         /* We assume the memory is from hugetlb until proved otherwise */
 145         umem->hugetlb   = 1;
 146
 147         page_list = (struct page **) __get_free_page(GFP_KERNEL);
 148         if (!page_list) {
 149                 kfree(umem);
 150                 return ERR_PTR(-ENOMEM);
 151         }
 152
 153         /*
 154          * if we can't alloc the vma_list, it's not so bad;
 155          * just assume the memory is not hugetlb memory
 156          */
 157         vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
 158         if (!vma_list)
 159                 umem->hugetlb = 0;
 160
 161         npages = ib_umem_num_pages(umem);
 162
 163         down_write(&current->mm->mmap_sem);
 164
 165         locked     = npages + current->mm->pinned_vm;
 166         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 167
 168         if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
 169                 ret = -ENOMEM;
 170                 goto out;
 171         }
 172
 173         cur_base = addr & PAGE_MASK;
 174
 175         if (npages == 0) {
 176                 ret = -EINVAL;
 177                 goto out;
 178         }
 179
 180         ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
 181         if (ret)
 182                 goto out;
 183
 184         need_release = 1;
 185         sg_list_start = umem->sg_head.sgl;
 186
 187         while (npages) {
 188                 ret = get_user_pages(current, current->mm, cur_base,
 189                                      min_t(unsigned long, npages,
 190                                            PAGE_SIZE / sizeof (struct page *)),
 191                                      1, !umem->writable, page_list, vma_list);
 192
 193                 if (ret < 0)
 194                         goto out;
 195
 196                 umem->npages += ret;
 197                 cur_base += ret * PAGE_SIZE;
 198                 npages   -= ret;
 199
 200                 for_each_sg(sg_list_start, sg, ret, i) {
 201                         if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
 202                                 umem->hugetlb = 0;
 203
 204                         sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
 205                 }
 206
 207                 /* preparing for next loop */
 208                 sg_list_start = sg;
 209         }
 210
 211         umem->nmap = ib_dma_map_sg_attrs(context->device,
 212                                   umem->sg_head.sgl,
 213                                   umem->npages,
 214                                   DMA_BIDIRECTIONAL,
 215                                   &attrs);
 216
 217         if (umem->nmap <= 0) {
 218                 ret = -ENOMEM;
 219                 goto out;
 220         }
 221
 222         ret = 0;
 223
 224 out:
 225         if (ret < 0) {
 226                 if (need_release)
 227                         __ib_umem_release(context->device, umem, 0);
 228                 put_pid(umem->pid);
 229                 kfree(umem);
 230         } else
 231                 current->mm->pinned_vm = locked;
 232
 233         up_write(&current->mm->mmap_sem);
 234         if (vma_list)
 235                 free_page((unsigned long) vma_list);
 236         free_page((unsigned long) page_list);
 237
 238         return ret < 0 ? ERR_PTR(ret) : umem;
 239 }
 240 EXPORT_SYMBOL(ib_umem_get);
 241
 242 static void ib_umem_account(struct work_struct *work)
 243 {
 244         struct ib_umem *umem = container_of(work, struct ib_umem, work);
 245
 246         down_write(&umem->mm->mmap_sem);
 247         umem->mm->pinned_vm -= umem->diff;
 248         up_write(&umem->mm->mmap_sem);
 249         mmput(umem->mm);
 250         kfree(umem);
 251 }
 252
 253 /**
 254  * ib_umem_release - release memory pinned with ib_umem_get
 255  * @umem: umem struct to release
 256  */
 257 void ib_umem_release(struct ib_umem *umem)
 258 {
 259         struct ib_ucontext *context = umem->context;
 260         struct mm_struct *mm;
 261         struct task_struct *task;
 262         unsigned long diff;
 263
 264         if (umem->odp_data) {
 265                 ib_umem_odp_release(umem);
 266                 return;
 267         }
 268
 269         __ib_umem_release(umem->context->device, umem, 1);
 270
 271         task = get_pid_task(umem->pid, PIDTYPE_PID);
 272         put_pid(umem->pid);
 273         if (!task)
 274                 goto out;
 275         mm = get_task_mm(task);
 276         put_task_struct(task);
 277         if (!mm)
 278                 goto out;
 279
 280         diff = ib_umem_num_pages(umem);
 281
 282         /*
 283          * We may be called with the mm's mmap_sem already held.  This
 284          * can happen when a userspace munmap() is the call that drops
 285          * the last reference to our file and calls our release
 286          * method.  If there are memory regions to destroy, we'll end
 287          * up here and not be able to take the mmap_sem.  In that case
 288          * we defer the vm_locked accounting to the system workqueue.
 289          */
 290         if (context->closing) {
 291                 if (!down_write_trylock(&mm->mmap_sem)) {
 292                         INIT_WORK(&umem->work, ib_umem_account);
 293                         umem->mm   = mm;
 294                         umem->diff = diff;
 295
 296                         queue_work(ib_wq, &umem->work);
 297                         return;
 298                 }
 299         } else
 300                 down_write(&mm->mmap_sem);
 301
 302         mm->pinned_vm -= diff;
 303         up_write(&mm->mmap_sem);
 304         mmput(mm);
 305 out:
 306         kfree(umem);
 307 }
 308 EXPORT_SYMBOL(ib_umem_release);
 309
 310 int ib_umem_page_count(struct ib_umem *umem)
 311 {
 312         int shift;
 313         int i;
 314         int n;
 315         struct scatterlist *sg;
 316
 317         if (umem->odp_data)
 318                 return ib_umem_num_pages(umem);
 319
 320         shift = ilog2(umem->page_size);
 321
 322         n = 0;
 323         for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
 324                 n += sg_dma_len(sg) >> shift;
 325
 326         return n;
 327 }
 328 EXPORT_SYMBOL(ib_umem_page_count);
 329
 330 /*
 331  * Copy from the given ib_umem's pages to the given buffer.
 332  *
 333  * umem - the umem to copy from
 334  * offset - offset to start copying from
 335  * dst - destination buffer
 336  * length - buffer length
 337  *
 338  * Returns 0 on success, or an error code.
 339  */
 340 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
 341                       size_t length)
 342 {
 343         size_t end = offset + length;
 344         int ret;
 345
 346         if (offset > umem->length || length > umem->length - offset) {
 347                 pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n",
 348                        offset, umem->length, end);
 349                 return -EINVAL;
 350         }
 351
 352         ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length,
 353                                  offset + ib_umem_offset(umem));
 354
 355         if (ret < 0)
 356                 return ret;
 357         else if (ret != length)
 358                 return -EINVAL;
 359         else
 360                 return 0;
 361 }
 362 EXPORT_SYMBOL(ib_umem_copy_from);