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1/*
2 * Copyright (c) 2006 Oracle. 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#include <linux/percpu.h>
34#include <linux/seq_file.h>
35#include <linux/slab.h>
36#include <linux/proc_fs.h>
37#include <linux/export.h>
38
39#include "rds.h"
40
41/*
42 * This file implements a getsockopt() call which copies a set of fixed
43 * sized structs into a user-specified buffer as a means of providing
44 * read-only information about RDS.
45 *
46 * For a given information source there are a given number of fixed sized
47 * structs at a given time. The structs are only copied if the user-specified
48 * buffer is big enough. The destination pages that make up the buffer
49 * are pinned for the duration of the copy.
50 *
51 * This gives us the following benefits:
52 *
53 * - simple implementation, no copy "position" across multiple calls
54 * - consistent snapshot of an info source
55 * - atomic copy works well with whatever locking info source has
56 * - one portable tool to get rds info across implementations
57 * - long-lived tool can get info without allocating
58 *
59 * at the following costs:
60 *
61 * - info source copy must be pinned, may be "large"
62 */
63
64struct rds_info_iterator {
65 struct page **pages;
66 void *addr;
67 unsigned long offset;
68};
69
70static DEFINE_SPINLOCK(rds_info_lock);
71static rds_info_func rds_info_funcs[RDS_INFO_LAST - RDS_INFO_FIRST + 1];
72
73void rds_info_register_func(int optname, rds_info_func func)
74{
75 int offset = optname - RDS_INFO_FIRST;
76
77 BUG_ON(optname < RDS_INFO_FIRST || optname > RDS_INFO_LAST);
78
79 spin_lock(&rds_info_lock);
80 BUG_ON(rds_info_funcs[offset]);
81 rds_info_funcs[offset] = func;
82 spin_unlock(&rds_info_lock);
83}
84EXPORT_SYMBOL_GPL(rds_info_register_func);
85
86void rds_info_deregister_func(int optname, rds_info_func func)
87{
88 int offset = optname - RDS_INFO_FIRST;
89
90 BUG_ON(optname < RDS_INFO_FIRST || optname > RDS_INFO_LAST);
91
92 spin_lock(&rds_info_lock);
93 BUG_ON(rds_info_funcs[offset] != func);
94 rds_info_funcs[offset] = NULL;
95 spin_unlock(&rds_info_lock);
96}
97EXPORT_SYMBOL_GPL(rds_info_deregister_func);
98
99/*
100 * Typically we hold an atomic kmap across multiple rds_info_copy() calls
101 * because the kmap is so expensive. This must be called before using blocking
102 * operations while holding the mapping and as the iterator is torn down.
103 */
104void rds_info_iter_unmap(struct rds_info_iterator *iter)
105{
106 if (iter->addr) {
107 kunmap_atomic(iter->addr);
108 iter->addr = NULL;
109 }
110}
111
112/*
113 * get_user_pages() called flush_dcache_page() on the pages for us.
114 */
115void rds_info_copy(struct rds_info_iterator *iter, void *data,
116 unsigned long bytes)
117{
118 unsigned long this;
119
120 while (bytes) {
121 if (!iter->addr)
122 iter->addr = kmap_atomic(*iter->pages);
123
124 this = min(bytes, PAGE_SIZE - iter->offset);
125
126 rdsdebug("page %p addr %p offset %lu this %lu data %p "
127 "bytes %lu\n", *iter->pages, iter->addr,
128 iter->offset, this, data, bytes);
129
130 memcpy(iter->addr + iter->offset, data, this);
131
132 data += this;
133 bytes -= this;
134 iter->offset += this;
135
136 if (iter->offset == PAGE_SIZE) {
137 kunmap_atomic(iter->addr);
138 iter->addr = NULL;
139 iter->offset = 0;
140 iter->pages++;
141 }
142 }
143}
144EXPORT_SYMBOL_GPL(rds_info_copy);
145
146/*
147 * @optval points to the userspace buffer that the information snapshot
148 * will be copied into.
149 *
150 * @optlen on input is the size of the buffer in userspace. @optlen
151 * on output is the size of the requested snapshot in bytes.
152 *
153 * This function returns -errno if there is a failure, particularly -ENOSPC
154 * if the given userspace buffer was not large enough to fit the snapshot.
155 * On success it returns the positive number of bytes of each array element
156 * in the snapshot.
157 */
158int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval,
159 int __user *optlen)
160{
161 struct rds_info_iterator iter;
162 struct rds_info_lengths lens;
163 unsigned long nr_pages = 0;
164 unsigned long start;
165 unsigned long i;
166 rds_info_func func;
167 struct page **pages = NULL;
168 int ret;
169 int len;
170 int total;
171
172 if (get_user(len, optlen)) {
173 ret = -EFAULT;
174 goto out;
175 }
176
177 /* check for all kinds of wrapping and the like */
178 start = (unsigned long)optval;
179 if (len < 0 || len > INT_MAX - PAGE_SIZE + 1 || start + len < start) {
180 ret = -EINVAL;
181 goto out;
182 }
183
184 /* a 0 len call is just trying to probe its length */
185 if (len == 0)
186 goto call_func;
187
188 nr_pages = (PAGE_ALIGN(start + len) - (start & PAGE_MASK))
189 >> PAGE_SHIFT;
190
191 pages = kmalloc(nr_pages * sizeof(struct page *), GFP_KERNEL);
192 if (!pages) {
193 ret = -ENOMEM;
194 goto out;
195 }
196 ret = get_user_pages_fast(start, nr_pages, 1, pages);
197 if (ret != nr_pages) {
198 if (ret > 0)
199 nr_pages = ret;
200 else
201 nr_pages = 0;
202 ret = -EAGAIN; /* XXX ? */
203 goto out;
204 }
205
206 rdsdebug("len %d nr_pages %lu\n", len, nr_pages);
207
208call_func:
209 func = rds_info_funcs[optname - RDS_INFO_FIRST];
210 if (!func) {
211 ret = -ENOPROTOOPT;
212 goto out;
213 }
214
215 iter.pages = pages;
216 iter.addr = NULL;
217 iter.offset = start & (PAGE_SIZE - 1);
218
219 func(sock, len, &iter, &lens);
220 BUG_ON(lens.each == 0);
221
222 total = lens.nr * lens.each;
223
224 rds_info_iter_unmap(&iter);
225
226 if (total > len) {
227 len = total;
228 ret = -ENOSPC;
229 } else {
230 len = total;
231 ret = lens.each;
232 }
233
234 if (put_user(len, optlen))
235 ret = -EFAULT;
236
237out:
238 for (i = 0; pages && i < nr_pages; i++)
239 put_page(pages[i]);
240 kfree(pages);
241
242 return ret;
243}
1/*
2 * Copyright (c) 2006 Oracle. 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#include <linux/percpu.h>
34#include <linux/seq_file.h>
35#include <linux/slab.h>
36#include <linux/proc_fs.h>
37
38#include "rds.h"
39
40/*
41 * This file implements a getsockopt() call which copies a set of fixed
42 * sized structs into a user-specified buffer as a means of providing
43 * read-only information about RDS.
44 *
45 * For a given information source there are a given number of fixed sized
46 * structs at a given time. The structs are only copied if the user-specified
47 * buffer is big enough. The destination pages that make up the buffer
48 * are pinned for the duration of the copy.
49 *
50 * This gives us the following benefits:
51 *
52 * - simple implementation, no copy "position" across multiple calls
53 * - consistent snapshot of an info source
54 * - atomic copy works well with whatever locking info source has
55 * - one portable tool to get rds info across implementations
56 * - long-lived tool can get info without allocating
57 *
58 * at the following costs:
59 *
60 * - info source copy must be pinned, may be "large"
61 */
62
63struct rds_info_iterator {
64 struct page **pages;
65 void *addr;
66 unsigned long offset;
67};
68
69static DEFINE_SPINLOCK(rds_info_lock);
70static rds_info_func rds_info_funcs[RDS_INFO_LAST - RDS_INFO_FIRST + 1];
71
72void rds_info_register_func(int optname, rds_info_func func)
73{
74 int offset = optname - RDS_INFO_FIRST;
75
76 BUG_ON(optname < RDS_INFO_FIRST || optname > RDS_INFO_LAST);
77
78 spin_lock(&rds_info_lock);
79 BUG_ON(rds_info_funcs[offset]);
80 rds_info_funcs[offset] = func;
81 spin_unlock(&rds_info_lock);
82}
83EXPORT_SYMBOL_GPL(rds_info_register_func);
84
85void rds_info_deregister_func(int optname, rds_info_func func)
86{
87 int offset = optname - RDS_INFO_FIRST;
88
89 BUG_ON(optname < RDS_INFO_FIRST || optname > RDS_INFO_LAST);
90
91 spin_lock(&rds_info_lock);
92 BUG_ON(rds_info_funcs[offset] != func);
93 rds_info_funcs[offset] = NULL;
94 spin_unlock(&rds_info_lock);
95}
96EXPORT_SYMBOL_GPL(rds_info_deregister_func);
97
98/*
99 * Typically we hold an atomic kmap across multiple rds_info_copy() calls
100 * because the kmap is so expensive. This must be called before using blocking
101 * operations while holding the mapping and as the iterator is torn down.
102 */
103void rds_info_iter_unmap(struct rds_info_iterator *iter)
104{
105 if (iter->addr) {
106 kunmap_atomic(iter->addr, KM_USER0);
107 iter->addr = NULL;
108 }
109}
110
111/*
112 * get_user_pages() called flush_dcache_page() on the pages for us.
113 */
114void rds_info_copy(struct rds_info_iterator *iter, void *data,
115 unsigned long bytes)
116{
117 unsigned long this;
118
119 while (bytes) {
120 if (!iter->addr)
121 iter->addr = kmap_atomic(*iter->pages, KM_USER0);
122
123 this = min(bytes, PAGE_SIZE - iter->offset);
124
125 rdsdebug("page %p addr %p offset %lu this %lu data %p "
126 "bytes %lu\n", *iter->pages, iter->addr,
127 iter->offset, this, data, bytes);
128
129 memcpy(iter->addr + iter->offset, data, this);
130
131 data += this;
132 bytes -= this;
133 iter->offset += this;
134
135 if (iter->offset == PAGE_SIZE) {
136 kunmap_atomic(iter->addr, KM_USER0);
137 iter->addr = NULL;
138 iter->offset = 0;
139 iter->pages++;
140 }
141 }
142}
143EXPORT_SYMBOL_GPL(rds_info_copy);
144
145/*
146 * @optval points to the userspace buffer that the information snapshot
147 * will be copied into.
148 *
149 * @optlen on input is the size of the buffer in userspace. @optlen
150 * on output is the size of the requested snapshot in bytes.
151 *
152 * This function returns -errno if there is a failure, particularly -ENOSPC
153 * if the given userspace buffer was not large enough to fit the snapshot.
154 * On success it returns the positive number of bytes of each array element
155 * in the snapshot.
156 */
157int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval,
158 int __user *optlen)
159{
160 struct rds_info_iterator iter;
161 struct rds_info_lengths lens;
162 unsigned long nr_pages = 0;
163 unsigned long start;
164 unsigned long i;
165 rds_info_func func;
166 struct page **pages = NULL;
167 int ret;
168 int len;
169 int total;
170
171 if (get_user(len, optlen)) {
172 ret = -EFAULT;
173 goto out;
174 }
175
176 /* check for all kinds of wrapping and the like */
177 start = (unsigned long)optval;
178 if (len < 0 || len + PAGE_SIZE - 1 < len || start + len < start) {
179 ret = -EINVAL;
180 goto out;
181 }
182
183 /* a 0 len call is just trying to probe its length */
184 if (len == 0)
185 goto call_func;
186
187 nr_pages = (PAGE_ALIGN(start + len) - (start & PAGE_MASK))
188 >> PAGE_SHIFT;
189
190 pages = kmalloc(nr_pages * sizeof(struct page *), GFP_KERNEL);
191 if (!pages) {
192 ret = -ENOMEM;
193 goto out;
194 }
195 ret = get_user_pages_fast(start, nr_pages, 1, pages);
196 if (ret != nr_pages) {
197 if (ret > 0)
198 nr_pages = ret;
199 else
200 nr_pages = 0;
201 ret = -EAGAIN; /* XXX ? */
202 goto out;
203 }
204
205 rdsdebug("len %d nr_pages %lu\n", len, nr_pages);
206
207call_func:
208 func = rds_info_funcs[optname - RDS_INFO_FIRST];
209 if (!func) {
210 ret = -ENOPROTOOPT;
211 goto out;
212 }
213
214 iter.pages = pages;
215 iter.addr = NULL;
216 iter.offset = start & (PAGE_SIZE - 1);
217
218 func(sock, len, &iter, &lens);
219 BUG_ON(lens.each == 0);
220
221 total = lens.nr * lens.each;
222
223 rds_info_iter_unmap(&iter);
224
225 if (total > len) {
226 len = total;
227 ret = -ENOSPC;
228 } else {
229 len = total;
230 ret = lens.each;
231 }
232
233 if (put_user(len, optlen))
234 ret = -EFAULT;
235
236out:
237 for (i = 0; pages && i < nr_pages; i++)
238 put_page(pages[i]);
239 kfree(pages);
240
241 return ret;
242}