include/rdma/uverbs_types.h

   1 /* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
   2 /*
   3  * Copyright (c) 2017, Mellanox Technologies inc.  All rights reserved.
   4  */
   5
   6 #ifndef _UVERBS_TYPES_
   7 #define _UVERBS_TYPES_
   8
   9 #include <linux/kernel.h>
  10 #include <rdma/ib_verbs.h>
  11
  12 struct uverbs_obj_type;
  13 struct uverbs_api_object;
  14
  15 enum rdma_lookup_mode {
  16         UVERBS_LOOKUP_READ,
  17         UVERBS_LOOKUP_WRITE,
  18         /*
  19          * Destroy is like LOOKUP_WRITE, except that the uobject is not
  20          * locked.  uobj_destroy is used to convert a LOOKUP_DESTROY lock into
  21          * a LOOKUP_WRITE lock.
  22          */
  23         UVERBS_LOOKUP_DESTROY,
  24 };
  25
  26 /*
  27  * The following sequences are valid:
  28  * Success flow:
  29  *   alloc_begin
  30  *   alloc_commit
  31  *    [..]
  32  * Access flow:
  33  *   lookup_get(exclusive=false) & uverbs_try_lock_object
  34  *   lookup_put(exclusive=false) via rdma_lookup_put_uobject
  35  * Destruction flow:
  36  *   lookup_get(exclusive=true) & uverbs_try_lock_object
  37  *   remove_commit
  38  *   remove_handle (optional)
  39  *   lookup_put(exclusive=true) via rdma_lookup_put_uobject
  40  *
  41  * Allocate Error flow #1
  42  *   alloc_begin
  43  *   alloc_abort
  44  * Allocate Error flow #2
  45  *   alloc_begin
  46  *   remove_commit
  47  *   alloc_abort
  48  * Allocate Error flow #3
  49  *   alloc_begin
  50  *   alloc_commit (fails)
  51  *   remove_commit
  52  *   alloc_abort
  53  *
  54  * In all cases the caller must hold the ufile kref until alloc_commit or
  55  * alloc_abort returns.
  56  */
  57 struct uverbs_obj_type_class {
  58         struct ib_uobject *(*alloc_begin)(const struct uverbs_api_object *obj,
  59                                           struct uverbs_attr_bundle *attrs);
  60         /* This consumes the kref on uobj */
  61         void (*alloc_commit)(struct ib_uobject *uobj);
  62         /* This does not consume the kref on uobj */
  63         void (*alloc_abort)(struct ib_uobject *uobj);
  64
  65         struct ib_uobject *(*lookup_get)(const struct uverbs_api_object *obj,
  66                                          struct ib_uverbs_file *ufile, s64 id,
  67                                          enum rdma_lookup_mode mode);
  68         void (*lookup_put)(struct ib_uobject *uobj, enum rdma_lookup_mode mode);
  69         /* This does not consume the kref on uobj */
  70         int __must_check (*destroy_hw)(struct ib_uobject *uobj,
  71                                        enum rdma_remove_reason why,
  72                                        struct uverbs_attr_bundle *attrs);
  73         void (*remove_handle)(struct ib_uobject *uobj);
  74         void (*swap_uobjects)(struct ib_uobject *obj_old,
  75                               struct ib_uobject *obj_new);
  76 };
  77
  78 struct uverbs_obj_type {
  79         const struct uverbs_obj_type_class * const type_class;
  80         size_t       obj_size;
  81 };
  82
  83 /*
  84  * Objects type classes which support a detach state (object is still alive but
  85  * it's not attached to any context need to make sure:
  86  * (a) no call through to a driver after a detach is called
  87  * (b) detach isn't called concurrently with context_cleanup
  88  */
  89
  90 struct uverbs_obj_idr_type {
  91         /*
  92          * In idr based objects, uverbs_obj_type_class points to a generic
  93          * idr operations. In order to specialize the underlying types (e.g. CQ,
  94          * QPs, etc.), we add destroy_object specific callbacks.
  95          */
  96         struct uverbs_obj_type  type;
  97
  98         /* Free driver resources from the uobject, make the driver uncallable,
  99          * and move the uobject to the detached state. If the object was
 100          * destroyed by the user's request, a failure should leave the uobject
 101          * completely unchanged.
 102          */
 103         int __must_check (*destroy_object)(struct ib_uobject *uobj,
 104                                            enum rdma_remove_reason why,
 105                                            struct uverbs_attr_bundle *attrs);
 106 };
 107
 108 struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_api_object *obj,
 109                                            struct ib_uverbs_file *ufile, s64 id,
 110                                            enum rdma_lookup_mode mode,
 111                                            struct uverbs_attr_bundle *attrs);
 112 void rdma_lookup_put_uobject(struct ib_uobject *uobj,
 113                              enum rdma_lookup_mode mode);
 114 struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_api_object *obj,
 115                                             struct uverbs_attr_bundle *attrs);
 116 void rdma_alloc_abort_uobject(struct ib_uobject *uobj,
 117                               struct uverbs_attr_bundle *attrs,
 118                               bool hw_obj_valid);
 119 void rdma_alloc_commit_uobject(struct ib_uobject *uobj,
 120                                struct uverbs_attr_bundle *attrs);
 121 void rdma_assign_uobject(struct ib_uobject *to_uobj,
 122                          struct ib_uobject *new_uobj,
 123                          struct uverbs_attr_bundle *attrs);
 124
 125 /*
 126  * uverbs_uobject_get is called in order to increase the reference count on
 127  * an uobject. This is useful when a handler wants to keep the uobject's memory
 128  * alive, regardless if this uobject is still alive in the context's objects
 129  * repository. Objects are put via uverbs_uobject_put.
 130  */
 131 static inline void uverbs_uobject_get(struct ib_uobject *uobject)
 132 {
 133         kref_get(&uobject->ref);
 134 }
 135 void uverbs_uobject_put(struct ib_uobject *uobject);
 136
 137 int uverbs_try_lock_object(struct ib_uobject *uobj, enum rdma_lookup_mode mode);
 138
 139 struct uverbs_obj_fd_type {
 140         /*
 141          * In fd based objects, uverbs_obj_type_ops points to generic
 142          * fd operations. In order to specialize the underlying types (e.g.
 143          * completion_channel), we use fops, name and flags for fd creation.
 144          * destroy_object is called when the uobject is to be destroyed,
 145          * because the driver is removed or the FD is closed.
 146          */
 147         struct uverbs_obj_type  type;
 148         void (*destroy_object)(struct ib_uobject *uobj,
 149                                enum rdma_remove_reason why);
 150         const struct file_operations    *fops;
 151         const char                      *name;
 152         int                             flags;
 153 };
 154
 155 struct ib_uverbs_file {
 156         struct kref                             ref;
 157         struct ib_uverbs_device                *device;
 158         struct mutex                            ucontext_lock;
 159         /*
 160          * ucontext must be accessed via ib_uverbs_get_ucontext() or with
 161          * ucontext_lock held
 162          */
 163         struct ib_ucontext                     *ucontext;
 164         struct ib_uverbs_async_event_file      *default_async_file;
 165         struct list_head                        list;
 166
 167         /*
 168          * To access the uobjects list hw_destroy_rwsem must be held for write
 169          * OR hw_destroy_rwsem held for read AND uobjects_lock held.
 170          * hw_destroy_rwsem should be called across any destruction of the HW
 171          * object of an associated uobject.
 172          */
 173         struct rw_semaphore     hw_destroy_rwsem;
 174         spinlock_t              uobjects_lock;
 175         struct list_head        uobjects;
 176
 177         struct mutex umap_lock;
 178         struct list_head umaps;
 179         struct page *disassociate_page;
 180
 181         struct xarray           idr;
 182
 183         struct mutex disassociation_lock;
 184 };
 185
 186 extern const struct uverbs_obj_type_class uverbs_idr_class;
 187 extern const struct uverbs_obj_type_class uverbs_fd_class;
 188 int uverbs_uobject_fd_release(struct inode *inode, struct file *filp);
 189
 190 #define UVERBS_BUILD_BUG_ON(cond) (sizeof(char[1 - 2 * !!(cond)]) -     \
 191                                    sizeof(char))
 192 #define UVERBS_TYPE_ALLOC_FD(_obj_size, _destroy_object, _fops, _name, _flags) \
 193         ((&((const struct uverbs_obj_fd_type)                           \
 194          {.type = {                                                     \
 195                 .type_class = &uverbs_fd_class,                         \
 196                 .obj_size = (_obj_size) +                               \
 197                         UVERBS_BUILD_BUG_ON((_obj_size) <               \
 198                                             sizeof(struct ib_uobject)), \
 199          },                                                             \
 200          .destroy_object = _destroy_object,                             \
 201          .fops = _fops,                                                 \
 202          .name = _name,                                                 \
 203          .flags = _flags}))->type)
 204 #define UVERBS_TYPE_ALLOC_IDR_SZ(_size, _destroy_object)        \
 205         ((&((const struct uverbs_obj_idr_type)                          \
 206          {.type = {                                                     \
 207                 .type_class = &uverbs_idr_class,                        \
 208                 .obj_size = (_size) +                                   \
 209                         UVERBS_BUILD_BUG_ON((_size) <                   \
 210                                             sizeof(struct ib_uobject))  \
 211          },                                                             \
 212          .destroy_object = _destroy_object,}))->type)
 213 #define UVERBS_TYPE_ALLOC_IDR(_destroy_object)                  \
 214          UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uobject),    \
 215                                   _destroy_object)
 216
 217 #endif