include/rdma/uverbs_types.h

   1 /*
   2  * Copyright (c) 2017, Mellanox Technologies inc.  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 _UVERBS_TYPES_
  34 #define _UVERBS_TYPES_
  35
  36 #include <linux/kernel.h>
  37 #include <rdma/ib_verbs.h>
  38
  39 struct uverbs_obj_type;
  40
  41 struct uverbs_obj_type_class {
  42         /*
  43          * Get an ib_uobject that corresponds to the given id from ucontext,
  44          * These functions could create or destroy objects if required.
  45          * The action will be finalized only when commit, abort or put fops are
  46          * called.
  47          * The flow of the different actions is:
  48          * [alloc]:      Starts with alloc_begin. The handlers logic is than
  49          *               executed. If the handler is successful, alloc_commit
  50          *               is called and the object is inserted to the repository.
  51          *               Once alloc_commit completes the object is visible to
  52          *               other threads and userspace.
  53          e               Otherwise, alloc_abort is called and the object is
  54          *               destroyed.
  55          * [lookup]:     Starts with lookup_get which fetches and locks the
  56          *               object. After the handler finished using the object, it
  57          *               needs to call lookup_put to unlock it. The exclusive
  58          *               flag indicates if the object is locked for exclusive
  59          *               access.
  60          * [remove]:     Starts with lookup_get with exclusive flag set. This
  61          *               locks the object for exclusive access. If the handler
  62          *               code completed successfully, remove_commit is called
  63          *               and the ib_uobject is removed from the context's
  64          *               uobjects repository and put. The object itself is
  65          *               destroyed as well. Once remove succeeds new krefs to
  66          *               the object cannot be acquired by other threads or
  67          *               userspace and the hardware driver is removed from the
  68          *               object. Other krefs on the object may still exist.
  69          *               If the handler code failed, lookup_put should be
  70          *               called. This callback is used when the context
  71          *               is destroyed as well (process termination,
  72          *               reset flow).
  73          */
  74         struct ib_uobject *(*alloc_begin)(const struct uverbs_obj_type *type,
  75                                           struct ib_ucontext *ucontext);
  76         void (*alloc_commit)(struct ib_uobject *uobj);
  77         void (*alloc_abort)(struct ib_uobject *uobj);
  78
  79         struct ib_uobject *(*lookup_get)(const struct uverbs_obj_type *type,
  80                                          struct ib_ucontext *ucontext, int id,
  81                                          bool exclusive);
  82         void (*lookup_put)(struct ib_uobject *uobj, bool exclusive);
  83         /*
  84          * Must be called with the exclusive lock held. If successful uobj is
  85          * invalid on return. On failure uobject is left completely
  86          * unchanged
  87          */
  88         int __must_check (*remove_commit)(struct ib_uobject *uobj,
  89                                           enum rdma_remove_reason why);
  90         u8    needs_kfree_rcu;
  91 };
  92
  93 struct uverbs_obj_type {
  94         const struct uverbs_obj_type_class * const type_class;
  95         size_t       obj_size;
  96         unsigned int destroy_order;
  97 };
  98
  99 /*
 100  * Objects type classes which support a detach state (object is still alive but
 101  * it's not attached to any context need to make sure:
 102  * (a) no call through to a driver after a detach is called
 103  * (b) detach isn't called concurrently with context_cleanup
 104  */
 105
 106 struct uverbs_obj_idr_type {
 107         /*
 108          * In idr based objects, uverbs_obj_type_class points to a generic
 109          * idr operations. In order to specialize the underlying types (e.g. CQ,
 110          * QPs, etc.), we add destroy_object specific callbacks.
 111          */
 112         struct uverbs_obj_type  type;
 113
 114         /* Free driver resources from the uobject, make the driver uncallable,
 115          * and move the uobject to the detached state. If the object was
 116          * destroyed by the user's request, a failure should leave the uobject
 117          * completely unchanged.
 118          */
 119         int __must_check (*destroy_object)(struct ib_uobject *uobj,
 120                                            enum rdma_remove_reason why);
 121 };
 122
 123 struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type,
 124                                            struct ib_ucontext *ucontext,
 125                                            int id, bool exclusive);
 126 void rdma_lookup_put_uobject(struct ib_uobject *uobj, bool exclusive);
 127 struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_obj_type *type,
 128                                             struct ib_ucontext *ucontext);
 129 void rdma_alloc_abort_uobject(struct ib_uobject *uobj);
 130 int __must_check rdma_remove_commit_uobject(struct ib_uobject *uobj);
 131 int rdma_alloc_commit_uobject(struct ib_uobject *uobj);
 132 int rdma_explicit_destroy(struct ib_uobject *uobject);
 133
 134 struct uverbs_obj_fd_type {
 135         /*
 136          * In fd based objects, uverbs_obj_type_ops points to generic
 137          * fd operations. In order to specialize the underlying types (e.g.
 138          * completion_channel), we use fops, name and flags for fd creation.
 139          * context_closed is called when the context is closed either when
 140          * the driver is removed or the process terminated.
 141          */
 142         struct uverbs_obj_type  type;
 143         int (*context_closed)(struct ib_uobject_file *uobj_file,
 144                               enum rdma_remove_reason why);
 145         const struct file_operations    *fops;
 146         const char                      *name;
 147         int                             flags;
 148 };
 149
 150 extern const struct uverbs_obj_type_class uverbs_idr_class;
 151 extern const struct uverbs_obj_type_class uverbs_fd_class;
 152
 153 #define UVERBS_BUILD_BUG_ON(cond) (sizeof(char[1 - 2 * !!(cond)]) -     \
 154                                    sizeof(char))
 155 #define UVERBS_TYPE_ALLOC_FD(_order, _obj_size, _context_closed, _fops, _name, _flags)\
 156         ((&((const struct uverbs_obj_fd_type)                           \
 157          {.type = {                                                     \
 158                 .destroy_order = _order,                                \
 159                 .type_class = &uverbs_fd_class,                         \
 160                 .obj_size = (_obj_size) +                               \
 161                         UVERBS_BUILD_BUG_ON((_obj_size) < sizeof(struct ib_uobject_file)), \
 162          },                                                             \
 163          .context_closed = _context_closed,                             \
 164          .fops = _fops,                                                 \
 165          .name = _name,                                                 \
 166          .flags = _flags}))->type)
 167 #define UVERBS_TYPE_ALLOC_IDR_SZ(_size, _order, _destroy_object)        \
 168         ((&((const struct uverbs_obj_idr_type)                          \
 169          {.type = {                                                     \
 170                 .destroy_order = _order,                                \
 171                 .type_class = &uverbs_idr_class,                        \
 172                 .obj_size = (_size) +                                   \
 173                         UVERBS_BUILD_BUG_ON((_size) <                   \
 174                                             sizeof(struct ib_uobject))  \
 175          },                                                             \
 176          .destroy_object = _destroy_object,}))->type)
 177 #define UVERBS_TYPE_ALLOC_IDR(_order, _destroy_object)                  \
 178          UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uobject), _order,    \
 179                                   _destroy_object)
 180
 181 #endif