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 struct uverbs_api_object;
41 
42 enum rdma_lookup_mode {
43 	UVERBS_LOOKUP_READ,
44 	UVERBS_LOOKUP_WRITE,
45 	/*
46 	 * Destroy is like LOOKUP_WRITE, except that the uobject is not
47 	 * locked.  uobj_destroy is used to convert a LOOKUP_DESTROY lock into
48 	 * a LOOKUP_WRITE lock.
49 	 */
50 	UVERBS_LOOKUP_DESTROY,
51 };
52 
53 /*
54  * The following sequences are valid:
55  * Success flow:
56  *   alloc_begin
57  *   alloc_commit
58  *    [..]
59  * Access flow:
60  *   lookup_get(exclusive=false) & uverbs_try_lock_object
61  *   lookup_put(exclusive=false) via rdma_lookup_put_uobject
62  * Destruction flow:
63  *   lookup_get(exclusive=true) & uverbs_try_lock_object
64  *   remove_commit
65  *   remove_handle (optional)
66  *   lookup_put(exclusive=true) via rdma_lookup_put_uobject
67  *
68  * Allocate Error flow #1
69  *   alloc_begin
70  *   alloc_abort
71  * Allocate Error flow #2
72  *   alloc_begin
73  *   remove_commit
74  *   alloc_abort
75  * Allocate Error flow #3
76  *   alloc_begin
77  *   alloc_commit (fails)
78  *   remove_commit
79  *   alloc_abort
80  *
81  * In all cases the caller must hold the ufile kref until alloc_commit or
82  * alloc_abort returns.
83  */
84 struct uverbs_obj_type_class {
85 	struct ib_uobject *(*alloc_begin)(const struct uverbs_api_object *obj,
86 					  struct ib_uverbs_file *ufile);
87 	/* This consumes the kref on uobj */
88 	int (*alloc_commit)(struct ib_uobject *uobj);
89 	/* This does not consume the kref on uobj */
90 	void (*alloc_abort)(struct ib_uobject *uobj);
91 
92 	struct ib_uobject *(*lookup_get)(const struct uverbs_api_object *obj,
93 					 struct ib_uverbs_file *ufile, s64 id,
94 					 enum rdma_lookup_mode mode);
95 	void (*lookup_put)(struct ib_uobject *uobj, enum rdma_lookup_mode mode);
96 	/* This does not consume the kref on uobj */
97 	int __must_check (*destroy_hw)(struct ib_uobject *uobj,
98 				       enum rdma_remove_reason why);
99 	void (*remove_handle)(struct ib_uobject *uobj);
100 	u8    needs_kfree_rcu;
101 };
102 
103 struct uverbs_obj_type {
104 	const struct uverbs_obj_type_class * const type_class;
105 	size_t	     obj_size;
106 };
107 
108 /*
109  * Objects type classes which support a detach state (object is still alive but
110  * it's not attached to any context need to make sure:
111  * (a) no call through to a driver after a detach is called
112  * (b) detach isn't called concurrently with context_cleanup
113  */
114 
115 struct uverbs_obj_idr_type {
116 	/*
117 	 * In idr based objects, uverbs_obj_type_class points to a generic
118 	 * idr operations. In order to specialize the underlying types (e.g. CQ,
119 	 * QPs, etc.), we add destroy_object specific callbacks.
120 	 */
121 	struct uverbs_obj_type  type;
122 
123 	/* Free driver resources from the uobject, make the driver uncallable,
124 	 * and move the uobject to the detached state. If the object was
125 	 * destroyed by the user's request, a failure should leave the uobject
126 	 * completely unchanged.
127 	 */
128 	int __must_check (*destroy_object)(struct ib_uobject *uobj,
129 					   enum rdma_remove_reason why);
130 };
131 
132 struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_api_object *obj,
133 					   struct ib_uverbs_file *ufile, s64 id,
134 					   enum rdma_lookup_mode mode);
135 void rdma_lookup_put_uobject(struct ib_uobject *uobj,
136 			     enum rdma_lookup_mode mode);
137 struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_api_object *obj,
138 					    struct ib_uverbs_file *ufile);
139 void rdma_alloc_abort_uobject(struct ib_uobject *uobj);
140 int __must_check rdma_alloc_commit_uobject(struct ib_uobject *uobj);
141 
142 struct uverbs_obj_fd_type {
143 	/*
144 	 * In fd based objects, uverbs_obj_type_ops points to generic
145 	 * fd operations. In order to specialize the underlying types (e.g.
146 	 * completion_channel), we use fops, name and flags for fd creation.
147 	 * context_closed is called when the context is closed either when
148 	 * the driver is removed or the process terminated.
149 	 */
150 	struct uverbs_obj_type  type;
151 	int (*context_closed)(struct ib_uobject *uobj,
152 			      enum rdma_remove_reason why);
153 	const struct file_operations	*fops;
154 	const char			*name;
155 	int				flags;
156 };
157 
158 extern const struct uverbs_obj_type_class uverbs_idr_class;
159 extern const struct uverbs_obj_type_class uverbs_fd_class;
160 
161 #define UVERBS_BUILD_BUG_ON(cond) (sizeof(char[1 - 2 * !!(cond)]) -	\
162 				   sizeof(char))
163 #define UVERBS_TYPE_ALLOC_FD(_obj_size, _context_closed, _fops, _name, _flags)\
164 	((&((const struct uverbs_obj_fd_type)				\
165 	 {.type = {							\
166 		.type_class = &uverbs_fd_class,				\
167 		.obj_size = (_obj_size) +				\
168 			UVERBS_BUILD_BUG_ON((_obj_size) <               \
169 					    sizeof(struct ib_uobject)), \
170 	 },								\
171 	 .context_closed = _context_closed,				\
172 	 .fops = _fops,							\
173 	 .name = _name,							\
174 	 .flags = _flags}))->type)
175 #define UVERBS_TYPE_ALLOC_IDR_SZ(_size, _destroy_object)	\
176 	((&((const struct uverbs_obj_idr_type)				\
177 	 {.type = {							\
178 		.type_class = &uverbs_idr_class,			\
179 		.obj_size = (_size) +					\
180 			UVERBS_BUILD_BUG_ON((_size) <			\
181 					    sizeof(struct ib_uobject))	\
182 	 },								\
183 	 .destroy_object = _destroy_object,}))->type)
184 #define UVERBS_TYPE_ALLOC_IDR(_destroy_object)			\
185 	 UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uobject),	\
186 				  _destroy_object)
187 
188 #endif
189