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  * Copyright (c) 2020 Intel Corporation. All rights reserved.
   6  *
   7  * This software is available to you under a choice of one of two
   8  * licenses.  You may choose to be licensed under the terms of the GNU
   9  * General Public License (GPL) Version 2, available from the file
  10  * COPYING in the main directory of this source tree, or the
  11  * OpenIB.org BSD license below:
  12  *
  13  *     Redistribution and use in source and binary forms, with or
  14  *     without modification, are permitted provided that the following
  15  *     conditions are met:
  16  *
  17  *      - Redistributions of source code must retain the above
  18  *        copyright notice, this list of conditions and the following
  19  *        disclaimer.
  20  *
  21  *      - Redistributions in binary form must reproduce the above
  22  *        copyright notice, this list of conditions and the following
  23  *        disclaimer in the documentation and/or other materials
  24  *        provided with the distribution.
  25  *
  26  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  30  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  31  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  32  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  33  * SOFTWARE.
  34  */
  35
  36 #include <linux/mm.h>
  37 #include <linux/dma-mapping.h>
  38 #include <linux/sched/signal.h>
  39 #include <linux/sched/mm.h>
  40 #include <linux/export.h>
  41 #include <linux/slab.h>
  42 #include <linux/pagemap.h>
  43 #include <linux/count_zeros.h>
  44 #include <rdma/ib_umem_odp.h>
  45
  46 #include "uverbs.h"
  47
  48 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
  49 {
  50         bool make_dirty = umem->writable && dirty;
  51         struct scatterlist *sg;
  52         unsigned int i;
  53
  54         if (dirty)
  55                 ib_dma_unmap_sgtable_attrs(dev, &umem->sgt_append.sgt,
  56                                            DMA_BIDIRECTIONAL, 0);
  57
  58         for_each_sgtable_sg(&umem->sgt_append.sgt, sg, i)
  59                 unpin_user_page_range_dirty_lock(sg_page(sg),
  60                         DIV_ROUND_UP(sg->length, PAGE_SIZE), make_dirty);
  61
  62         sg_free_append_table(&umem->sgt_append);
  63 }
  64
  65 /**
  66  * ib_umem_find_best_pgsz - Find best HW page size to use for this MR
  67  *
  68  * @umem: umem struct
  69  * @pgsz_bitmap: bitmap of HW supported page sizes
  70  * @virt: IOVA
  71  *
  72  * This helper is intended for HW that support multiple page
  73  * sizes but can do only a single page size in an MR.
  74  *
  75  * Returns 0 if the umem requires page sizes not supported by
  76  * the driver to be mapped. Drivers always supporting PAGE_SIZE
  77  * or smaller will never see a 0 result.
  78  */
  79 unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
  80                                      unsigned long pgsz_bitmap,
  81                                      unsigned long virt)
  82 {
  83         struct scatterlist *sg;
  84         unsigned long va, pgoff;
  85         dma_addr_t mask;
  86         int i;
  87
  88         umem->iova = va = virt;
  89
  90         if (umem->is_odp) {
  91                 unsigned int page_size = BIT(to_ib_umem_odp(umem)->page_shift);
  92
  93                 /* ODP must always be self consistent. */
  94                 if (!(pgsz_bitmap & page_size))
  95                         return 0;
  96                 return page_size;
  97         }
  98
  99         /* The best result is the smallest page size that results in the minimum
 100          * number of required pages. Compute the largest page size that could
 101          * work based on VA address bits that don't change.
 102          */
 103         mask = pgsz_bitmap &
 104                GENMASK(BITS_PER_LONG - 1,
 105                        bits_per((umem->length - 1 + virt) ^ virt));
 106         /* offset into first SGL */
 107         pgoff = umem->address & ~PAGE_MASK;
 108
 109         for_each_sgtable_dma_sg(&umem->sgt_append.sgt, sg, i) {
 110                 /* Walk SGL and reduce max page size if VA/PA bits differ
 111                  * for any address.
 112                  */
 113                 mask |= (sg_dma_address(sg) + pgoff) ^ va;
 114                 va += sg_dma_len(sg) - pgoff;
 115                 /* Except for the last entry, the ending iova alignment sets
 116                  * the maximum possible page size as the low bits of the iova
 117                  * must be zero when starting the next chunk.
 118                  */
 119                 if (i != (umem->sgt_append.sgt.nents - 1))
 120                         mask |= va;
 121                 pgoff = 0;
 122         }
 123
 124         /* The mask accumulates 1's in each position where the VA and physical
 125          * address differ, thus the length of trailing 0 is the largest page
 126          * size that can pass the VA through to the physical.
 127          */
 128         if (mask)
 129                 pgsz_bitmap &= GENMASK(count_trailing_zeros(mask), 0);
 130         return pgsz_bitmap ? rounddown_pow_of_two(pgsz_bitmap) : 0;
 131 }
 132 EXPORT_SYMBOL(ib_umem_find_best_pgsz);
 133
 134 /**
 135  * ib_umem_get - Pin and DMA map userspace memory.
 136  *
 137  * @device: IB device to connect UMEM
 138  * @addr: userspace virtual address to start at
 139  * @size: length of region to pin
 140  * @access: IB_ACCESS_xxx flags for memory being pinned
 141  */
 142 struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
 143                             size_t size, int access)
 144 {
 145         struct ib_umem *umem;
 146         struct page **page_list;
 147         unsigned long lock_limit;
 148         unsigned long new_pinned;
 149         unsigned long cur_base;
 150         unsigned long dma_attr = 0;
 151         struct mm_struct *mm;
 152         unsigned long npages;
 153         int pinned, ret;
 154         unsigned int gup_flags = FOLL_LONGTERM;
 155
 156         /*
 157          * If the combination of the addr and size requested for this memory
 158          * region causes an integer overflow, return error.
 159          */
 160         if (((addr + size) < addr) ||
 161             PAGE_ALIGN(addr + size) < (addr + size))
 162                 return ERR_PTR(-EINVAL);
 163
 164         if (!can_do_mlock())
 165                 return ERR_PTR(-EPERM);
 166
 167         if (access & IB_ACCESS_ON_DEMAND)
 168                 return ERR_PTR(-EOPNOTSUPP);
 169
 170         umem = kzalloc(sizeof(*umem), GFP_KERNEL);
 171         if (!umem)
 172                 return ERR_PTR(-ENOMEM);
 173         umem->ibdev      = device;
 174         umem->length     = size;
 175         umem->address    = addr;
 176         /*
 177          * Drivers should call ib_umem_find_best_pgsz() to set the iova
 178          * correctly.
 179          */
 180         umem->iova = addr;
 181         umem->writable   = ib_access_writable(access);
 182         umem->owning_mm = mm = current->mm;
 183         mmgrab(mm);
 184
 185         page_list = (struct page **) __get_free_page(GFP_KERNEL);
 186         if (!page_list) {
 187                 ret = -ENOMEM;
 188                 goto umem_kfree;
 189         }
 190
 191         npages = ib_umem_num_pages(umem);
 192         if (npages == 0 || npages > UINT_MAX) {
 193                 ret = -EINVAL;
 194                 goto out;
 195         }
 196
 197         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 198
 199         new_pinned = atomic64_add_return(npages, &mm->pinned_vm);
 200         if (new_pinned > lock_limit && !capable(CAP_IPC_LOCK)) {
 201                 atomic64_sub(npages, &mm->pinned_vm);
 202                 ret = -ENOMEM;
 203                 goto out;
 204         }
 205
 206         cur_base = addr & PAGE_MASK;
 207
 208         if (umem->writable)
 209                 gup_flags |= FOLL_WRITE;
 210
 211         while (npages) {
 212                 cond_resched();
 213                 pinned = pin_user_pages_fast(cur_base,
 214                                           min_t(unsigned long, npages,
 215                                                 PAGE_SIZE /
 216                                                 sizeof(struct page *)),
 217                                           gup_flags, page_list);
 218                 if (pinned < 0) {
 219                         ret = pinned;
 220                         goto umem_release;
 221                 }
 222
 223                 cur_base += pinned * PAGE_SIZE;
 224                 npages -= pinned;
 225                 ret = sg_alloc_append_table_from_pages(
 226                         &umem->sgt_append, page_list, pinned, 0,
 227                         pinned << PAGE_SHIFT, ib_dma_max_seg_size(device),
 228                         npages, GFP_KERNEL);
 229                 if (ret) {
 230                         unpin_user_pages_dirty_lock(page_list, pinned, 0);
 231                         goto umem_release;
 232                 }
 233         }
 234
 235         if (access & IB_ACCESS_RELAXED_ORDERING)
 236                 dma_attr |= DMA_ATTR_WEAK_ORDERING;
 237
 238         ret = ib_dma_map_sgtable_attrs(device, &umem->sgt_append.sgt,
 239                                        DMA_BIDIRECTIONAL, dma_attr);
 240         if (ret)
 241                 goto umem_release;
 242         goto out;
 243
 244 umem_release:
 245         __ib_umem_release(device, umem, 0);
 246         atomic64_sub(ib_umem_num_pages(umem), &mm->pinned_vm);
 247 out:
 248         free_page((unsigned long) page_list);
 249 umem_kfree:
 250         if (ret) {
 251                 mmdrop(umem->owning_mm);
 252                 kfree(umem);
 253         }
 254         return ret ? ERR_PTR(ret) : umem;
 255 }
 256 EXPORT_SYMBOL(ib_umem_get);
 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         if (!umem)
 265                 return;
 266         if (umem->is_dmabuf)
 267                 return ib_umem_dmabuf_release(to_ib_umem_dmabuf(umem));
 268         if (umem->is_odp)
 269                 return ib_umem_odp_release(to_ib_umem_odp(umem));
 270
 271         __ib_umem_release(umem->ibdev, umem, 1);
 272
 273         atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm);
 274         mmdrop(umem->owning_mm);
 275         kfree(umem);
 276 }
 277 EXPORT_SYMBOL(ib_umem_release);
 278
 279 /*
 280  * Copy from the given ib_umem's pages to the given buffer.
 281  *
 282  * umem - the umem to copy from
 283  * offset - offset to start copying from
 284  * dst - destination buffer
 285  * length - buffer length
 286  *
 287  * Returns 0 on success, or an error code.
 288  */
 289 int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
 290                       size_t length)
 291 {
 292         size_t end = offset + length;
 293         int ret;
 294
 295         if (offset > umem->length || length > umem->length - offset) {
 296                 pr_err("%s not in range. offset: %zd umem length: %zd end: %zd\n",
 297                        __func__, offset, umem->length, end);
 298                 return -EINVAL;
 299         }
 300
 301         ret = sg_pcopy_to_buffer(umem->sgt_append.sgt.sgl,
 302                                  umem->sgt_append.sgt.orig_nents, dst, length,
 303                                  offset + ib_umem_offset(umem));
 304
 305         if (ret < 0)
 306                 return ret;
 307         else if (ret != length)
 308                 return -EINVAL;
 309         else
 310                 return 0;
 311 }
 312 EXPORT_SYMBOL(ib_umem_copy_from);