include/rdma/ib_umem_odp.h

   1 /*
   2  * Copyright (c) 2014 Mellanox Technologies. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32
  33 #ifndef IB_UMEM_ODP_H
  34 #define IB_UMEM_ODP_H
  35
  36 #include <rdma/ib_umem.h>
  37 #include <rdma/ib_verbs.h>
  38 #include <linux/interval_tree.h>
  39
  40 struct umem_odp_node {
  41         u64 __subtree_last;
  42         struct rb_node rb;
  43 };
  44
  45 struct ib_umem_odp {
  46         /*
  47          * An array of the pages included in the on-demand paging umem.
  48          * Indices of pages that are currently not mapped into the device will
  49          * contain NULL.
  50          */
  51         struct page             **page_list;
  52         /*
  53          * An array of the same size as page_list, with DMA addresses mapped
  54          * for pages the pages in page_list. The lower two bits designate
  55          * access permissions. See ODP_READ_ALLOWED_BIT and
  56          * ODP_WRITE_ALLOWED_BIT.
  57          */
  58         dma_addr_t              *dma_list;
  59         /*
  60          * The umem_mutex protects the page_list and dma_list fields of an ODP
  61          * umem, allowing only a single thread to map/unmap pages. The mutex
  62          * also protects access to the mmu notifier counters.
  63          */
  64         struct mutex            umem_mutex;
  65         void                    *private; /* for the HW driver to use. */
  66
  67         /* When false, use the notifier counter in the ucontext struct. */
  68         bool mn_counters_active;
  69         int notifiers_seq;
  70         int notifiers_count;
  71
  72         /* A linked list of umems that don't have private mmu notifier
  73          * counters yet. */
  74         struct list_head no_private_counters;
  75         struct ib_umem          *umem;
  76
  77         /* Tree tracking */
  78         struct umem_odp_node    interval_tree;
  79
  80         struct completion       notifier_completion;
  81         int                     dying;
  82         struct work_struct      work;
  83 };
  84
  85 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
  86
  87 int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem,
  88                     int access);
  89 struct ib_umem *ib_alloc_odp_umem(struct ib_ucontext *context,
  90                                   unsigned long addr,
  91                                   size_t size);
  92
  93 void ib_umem_odp_release(struct ib_umem *umem);
  94
  95 /*
  96  * The lower 2 bits of the DMA address signal the R/W permissions for
  97  * the entry. To upgrade the permissions, provide the appropriate
  98  * bitmask to the map_dma_pages function.
  99  *
 100  * Be aware that upgrading a mapped address might result in change of
 101  * the DMA address for the page.
 102  */
 103 #define ODP_READ_ALLOWED_BIT  (1<<0ULL)
 104 #define ODP_WRITE_ALLOWED_BIT (1<<1ULL)
 105
 106 #define ODP_DMA_ADDR_MASK (~(ODP_READ_ALLOWED_BIT | ODP_WRITE_ALLOWED_BIT))
 107
 108 int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 start_offset, u64 bcnt,
 109                               u64 access_mask, unsigned long current_seq);
 110
 111 void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 start_offset,
 112                                  u64 bound);
 113
 114 typedef int (*umem_call_back)(struct ib_umem *item, u64 start, u64 end,
 115                               void *cookie);
 116 /*
 117  * Call the callback on each ib_umem in the range. Returns the logical or of
 118  * the return values of the functions called.
 119  */
 120 int rbt_ib_umem_for_each_in_range(struct rb_root_cached *root,
 121                                   u64 start, u64 end,
 122                                   umem_call_back cb, void *cookie);
 123
 124 /*
 125  * Find first region intersecting with address range.
 126  * Return NULL if not found
 127  */
 128 struct ib_umem_odp *rbt_ib_umem_lookup(struct rb_root_cached *root,
 129                                        u64 addr, u64 length);
 130
 131 static inline int ib_umem_mmu_notifier_retry(struct ib_umem *item,
 132                                              unsigned long mmu_seq)
 133 {
 134         /*
 135          * This code is strongly based on the KVM code from
 136          * mmu_notifier_retry. Should be called with
 137          * the relevant locks taken (item->odp_data->umem_mutex
 138          * and the ucontext umem_mutex semaphore locked for read).
 139          */
 140
 141         /* Do not allow page faults while the new ib_umem hasn't seen a state
 142          * with zero notifiers yet, and doesn't have its own valid set of
 143          * private counters. */
 144         if (!item->odp_data->mn_counters_active)
 145                 return 1;
 146
 147         if (unlikely(item->odp_data->notifiers_count))
 148                 return 1;
 149         if (item->odp_data->notifiers_seq != mmu_seq)
 150                 return 1;
 151         return 0;
 152 }
 153
 154 #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 155
 156 static inline int ib_umem_odp_get(struct ib_ucontext *context,
 157                                   struct ib_umem *umem,
 158                                   int access)
 159 {
 160         return -EINVAL;
 161 }
 162
 163 static inline struct ib_umem *ib_alloc_odp_umem(struct ib_ucontext *context,
 164                                                 unsigned long addr,
 165                                                 size_t size)
 166 {
 167         return ERR_PTR(-EINVAL);
 168 }
 169
 170 static inline void ib_umem_odp_release(struct ib_umem *umem) {}
 171
 172 #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 173
 174 #endif /* IB_UMEM_ODP_H */