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         struct ib_umem umem;
  47         struct ib_ucontext_per_mm *per_mm;
  48
  49         /*
  50          * An array of the pages included in the on-demand paging umem.
  51          * Indices of pages that are currently not mapped into the device will
  52          * contain NULL.
  53          */
  54         struct page             **page_list;
  55         /*
  56          * An array of the same size as page_list, with DMA addresses mapped
  57          * for pages the pages in page_list. The lower two bits designate
  58          * access permissions. See ODP_READ_ALLOWED_BIT and
  59          * ODP_WRITE_ALLOWED_BIT.
  60          */
  61         dma_addr_t              *dma_list;
  62         /*
  63          * The umem_mutex protects the page_list and dma_list fields of an ODP
  64          * umem, allowing only a single thread to map/unmap pages. The mutex
  65          * also protects access to the mmu notifier counters.
  66          */
  67         struct mutex            umem_mutex;
  68         void                    *private; /* for the HW driver to use. */
  69
  70         int notifiers_seq;
  71         int notifiers_count;
  72
  73         /* Tree tracking */
  74         struct umem_odp_node    interval_tree;
  75
  76         struct completion       notifier_completion;
  77         int                     dying;
  78         struct work_struct      work;
  79 };
  80
  81 static inline struct ib_umem_odp *to_ib_umem_odp(struct ib_umem *umem)
  82 {
  83         return container_of(umem, struct ib_umem_odp, umem);
  84 }
  85
  86 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
  87
  88 struct ib_ucontext_per_mm {
  89         struct ib_ucontext *context;
  90         struct mm_struct *mm;
  91         struct pid *tgid;
  92         bool active;
  93
  94         struct rb_root_cached umem_tree;
  95         /* Protects umem_tree */
  96         struct rw_semaphore umem_rwsem;
  97
  98         struct mmu_notifier mn;
  99         unsigned int odp_mrs_count;
 100
 101         struct list_head ucontext_list;
 102         struct rcu_head rcu;
 103 };
 104
 105 int ib_umem_odp_get(struct ib_umem_odp *umem_odp, int access);
 106 struct ib_umem_odp *ib_alloc_odp_umem(struct ib_ucontext_per_mm *per_mm,
 107                                       unsigned long addr, size_t size);
 108 void ib_umem_odp_release(struct ib_umem_odp *umem_odp);
 109
 110 /*
 111  * The lower 2 bits of the DMA address signal the R/W permissions for
 112  * the entry. To upgrade the permissions, provide the appropriate
 113  * bitmask to the map_dma_pages function.
 114  *
 115  * Be aware that upgrading a mapped address might result in change of
 116  * the DMA address for the page.
 117  */
 118 #define ODP_READ_ALLOWED_BIT  (1<<0ULL)
 119 #define ODP_WRITE_ALLOWED_BIT (1<<1ULL)
 120
 121 #define ODP_DMA_ADDR_MASK (~(ODP_READ_ALLOWED_BIT | ODP_WRITE_ALLOWED_BIT))
 122
 123 int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 start_offset,
 124                               u64 bcnt, u64 access_mask,
 125                               unsigned long current_seq);
 126
 127 void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 start_offset,
 128                                  u64 bound);
 129
 130 typedef int (*umem_call_back)(struct ib_umem_odp *item, u64 start, u64 end,
 131                               void *cookie);
 132 /*
 133  * Call the callback on each ib_umem in the range. Returns the logical or of
 134  * the return values of the functions called.
 135  */
 136 int rbt_ib_umem_for_each_in_range(struct rb_root_cached *root,
 137                                   u64 start, u64 end,
 138                                   umem_call_back cb,
 139                                   bool blockable, void *cookie);
 140
 141 /*
 142  * Find first region intersecting with address range.
 143  * Return NULL if not found
 144  */
 145 struct ib_umem_odp *rbt_ib_umem_lookup(struct rb_root_cached *root,
 146                                        u64 addr, u64 length);
 147
 148 static inline int ib_umem_mmu_notifier_retry(struct ib_umem_odp *umem_odp,
 149                                              unsigned long mmu_seq)
 150 {
 151         /*
 152          * This code is strongly based on the KVM code from
 153          * mmu_notifier_retry. Should be called with
 154          * the relevant locks taken (umem_odp->umem_mutex
 155          * and the ucontext umem_mutex semaphore locked for read).
 156          */
 157
 158         if (unlikely(umem_odp->notifiers_count))
 159                 return 1;
 160         if (umem_odp->notifiers_seq != mmu_seq)
 161                 return 1;
 162         return 0;
 163 }
 164
 165 #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 166
 167 static inline int ib_umem_odp_get(struct ib_umem_odp *umem_odp, int access)
 168 {
 169         return -EINVAL;
 170 }
 171
 172 static inline struct ib_umem_odp *
 173 ib_alloc_odp_umem(struct ib_ucontext *context, unsigned long addr, size_t size)
 174 {
 175         return ERR_PTR(-EINVAL);
 176 }
 177
 178 static inline void ib_umem_odp_release(struct ib_umem_odp *umem_odp) {}
 179
 180 #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 181
 182 #endif /* IB_UMEM_ODP_H */