1 | /* $NetBSD: dm_table.c,v 1.7 2011/08/27 17:10:05 ahoka Exp $ */ |
2 | |
3 | /* |
4 | * Copyright (c) 2008 The NetBSD Foundation, Inc. |
5 | * All rights reserved. |
6 | * |
7 | * This code is derived from software contributed to The NetBSD Foundation |
8 | * by Adam Hamsik. |
9 | * |
10 | * Redistribution and use in source and binary forms, with or without |
11 | * modification, are permitted provided that the following conditions |
12 | * are met: |
13 | * 1. Redistributions of source code must retain the above copyright |
14 | * notice, this list of conditions and the following disclaimer. |
15 | * 2. Redistributions in binary form must reproduce the above copyright |
16 | * notice, this list of conditions and the following disclaimer in the |
17 | * documentation and/or other materials provided with the distribution. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
29 | * POSSIBILITY OF SUCH DAMAGE. |
30 | */ |
31 | |
32 | #include <sys/types.h> |
33 | #include <sys/param.h> |
34 | |
35 | #include <sys/kmem.h> |
36 | |
37 | #include "dm.h" |
38 | |
39 | /* |
40 | * There are two types of users of this interface: |
41 | * |
42 | * a) Readers such as |
43 | * dmstrategy, dmgetdisklabel, dmsize, dm_dev_status_ioctl, |
44 | * dm_table_deps_ioctl, dm_table_status_ioctl, dm_table_reload_ioctl |
45 | * |
46 | * b) Writers such as |
47 | * dm_dev_remove_ioctl, dm_dev_resume_ioctl, dm_table_clear_ioctl |
48 | * |
49 | * Writers can work with table_head only when there are no readers. I |
50 | * use reference counting on io_cnt. |
51 | * |
52 | */ |
53 | |
54 | static int dm_table_busy(dm_table_head_t *, uint8_t); |
55 | static void dm_table_unbusy(dm_table_head_t *); |
56 | |
57 | /* |
58 | * Function to increment table user reference counter. Return id |
59 | * of table_id table. |
60 | * DM_TABLE_ACTIVE will return active table id. |
61 | * DM_TABLE_INACTIVE will return inactive table id. |
62 | */ |
63 | static int |
64 | dm_table_busy(dm_table_head_t * head, uint8_t table_id) |
65 | { |
66 | uint8_t id; |
67 | |
68 | id = 0; |
69 | |
70 | mutex_enter(&head->table_mtx); |
71 | |
72 | if (table_id == DM_TABLE_ACTIVE) |
73 | id = head->cur_active_table; |
74 | else |
75 | id = 1 - head->cur_active_table; |
76 | |
77 | head->io_cnt++; |
78 | |
79 | mutex_exit(&head->table_mtx); |
80 | return id; |
81 | } |
82 | /* |
83 | * Function release table lock and eventually wakeup all waiters. |
84 | */ |
85 | static void |
86 | dm_table_unbusy(dm_table_head_t * head) |
87 | { |
88 | KASSERT(head->io_cnt != 0); |
89 | |
90 | mutex_enter(&head->table_mtx); |
91 | |
92 | if (--head->io_cnt == 0) |
93 | cv_broadcast(&head->table_cv); |
94 | |
95 | mutex_exit(&head->table_mtx); |
96 | } |
97 | /* |
98 | * Return current active table to caller, increment io_cnt reference counter. |
99 | */ |
100 | dm_table_t * |
101 | dm_table_get_entry(dm_table_head_t * head, uint8_t table_id) |
102 | { |
103 | uint8_t id; |
104 | |
105 | id = dm_table_busy(head, table_id); |
106 | |
107 | return &head->tables[id]; |
108 | } |
109 | /* |
110 | * Decrement io reference counter and wake up all callers, with table_head cv. |
111 | */ |
112 | void |
113 | dm_table_release(dm_table_head_t * head, uint8_t table_id) |
114 | { |
115 | dm_table_unbusy(head); |
116 | } |
117 | /* |
118 | * Switch table from inactive to active mode. Have to wait until io_cnt is 0. |
119 | */ |
120 | void |
121 | dm_table_switch_tables(dm_table_head_t * head) |
122 | { |
123 | mutex_enter(&head->table_mtx); |
124 | |
125 | while (head->io_cnt != 0) |
126 | cv_wait(&head->table_cv, &head->table_mtx); |
127 | |
128 | head->cur_active_table = 1 - head->cur_active_table; |
129 | |
130 | mutex_exit(&head->table_mtx); |
131 | } |
132 | /* |
133 | * Destroy all table data. This function can run when there are no |
134 | * readers on table lists. |
135 | * |
136 | * XXX Is it ok to call kmem_free and potentialy VOP_CLOSE with held mutex ?xs |
137 | */ |
138 | int |
139 | dm_table_destroy(dm_table_head_t * head, uint8_t table_id) |
140 | { |
141 | dm_table_t *tbl; |
142 | dm_table_entry_t *table_en; |
143 | uint8_t id; |
144 | |
145 | mutex_enter(&head->table_mtx); |
146 | |
147 | aprint_debug("dm_Table_destroy called with %d--%d\n" , table_id, head->io_cnt); |
148 | |
149 | while (head->io_cnt != 0) |
150 | cv_wait(&head->table_cv, &head->table_mtx); |
151 | |
152 | if (table_id == DM_TABLE_ACTIVE) |
153 | id = head->cur_active_table; |
154 | else |
155 | id = 1 - head->cur_active_table; |
156 | |
157 | tbl = &head->tables[id]; |
158 | |
159 | while (!SLIST_EMPTY(tbl)) { /* List Deletion. */ |
160 | table_en = SLIST_FIRST(tbl); |
161 | /* |
162 | * Remove target specific config data. After successfull |
163 | * call table_en->target_config must be set to NULL. |
164 | */ |
165 | table_en->target->destroy(table_en); |
166 | |
167 | SLIST_REMOVE_HEAD(tbl, next); |
168 | |
169 | kmem_free(table_en, sizeof(*table_en)); |
170 | } |
171 | |
172 | mutex_exit(&head->table_mtx); |
173 | |
174 | return 0; |
175 | } |
176 | /* |
177 | * Return length of active table in device. |
178 | */ |
179 | static inline uint64_t |
180 | dm_table_size_impl(dm_table_head_t * head, int table) |
181 | { |
182 | dm_table_t *tbl; |
183 | dm_table_entry_t *table_en; |
184 | uint64_t length; |
185 | uint8_t id; |
186 | |
187 | length = 0; |
188 | |
189 | id = dm_table_busy(head, table); |
190 | |
191 | /* Select active table */ |
192 | tbl = &head->tables[id]; |
193 | |
194 | /* |
195 | * Find out what tables I want to select. |
196 | * if length => rawblkno then we should used that table. |
197 | */ |
198 | SLIST_FOREACH(table_en, tbl, next) |
199 | length += table_en->length; |
200 | |
201 | dm_table_unbusy(head); |
202 | |
203 | return length; |
204 | } |
205 | |
206 | /* |
207 | * Return length of active table in device. |
208 | */ |
209 | uint64_t |
210 | dm_table_size(dm_table_head_t * head) |
211 | { |
212 | return dm_table_size_impl(head, DM_TABLE_ACTIVE); |
213 | } |
214 | |
215 | /* |
216 | * Return length of active table in device. |
217 | */ |
218 | uint64_t |
219 | dm_inactive_table_size(dm_table_head_t * head) |
220 | { |
221 | return dm_table_size_impl(head, DM_TABLE_INACTIVE); |
222 | } |
223 | |
224 | /* |
225 | * Return combined disk geometry |
226 | */ |
227 | void |
228 | dm_table_disksize(dm_table_head_t * head, uint64_t *numsecp, unsigned *secsizep) |
229 | { |
230 | dm_table_t *tbl; |
231 | dm_table_entry_t *table_en; |
232 | uint64_t length; |
233 | unsigned secsize, tsecsize; |
234 | uint8_t id; |
235 | |
236 | length = 0; |
237 | |
238 | id = dm_table_busy(head, DM_TABLE_ACTIVE); |
239 | |
240 | /* Select active table */ |
241 | tbl = &head->tables[id]; |
242 | |
243 | /* |
244 | * Find out what tables I want to select. |
245 | * if length => rawblkno then we should used that table. |
246 | */ |
247 | secsize = 0; |
248 | SLIST_FOREACH(table_en, tbl, next) { |
249 | length += table_en->length; |
250 | (void)table_en->target->secsize(table_en, &tsecsize); |
251 | if (secsize < tsecsize) |
252 | secsize = tsecsize; |
253 | } |
254 | *numsecp = secsize > 0 ? dbtob(length) / secsize : 0; |
255 | *secsizep = secsize; |
256 | |
257 | dm_table_unbusy(head); |
258 | } |
259 | /* |
260 | * Return > 0 if table is at least one table entry (returns number of entries) |
261 | * and return 0 if there is not. Target count returned from this function |
262 | * doesn't need to be true when userspace user receive it (after return |
263 | * there can be dm_dev_resume_ioctl), therfore this isonly informative. |
264 | */ |
265 | int |
266 | dm_table_get_target_count(dm_table_head_t * head, uint8_t table_id) |
267 | { |
268 | dm_table_entry_t *table_en; |
269 | dm_table_t *tbl; |
270 | uint32_t target_count; |
271 | uint8_t id; |
272 | |
273 | target_count = 0; |
274 | |
275 | id = dm_table_busy(head, table_id); |
276 | |
277 | tbl = &head->tables[id]; |
278 | |
279 | SLIST_FOREACH(table_en, tbl, next) |
280 | target_count++; |
281 | |
282 | dm_table_unbusy(head); |
283 | |
284 | return target_count; |
285 | } |
286 | |
287 | |
288 | /* |
289 | * Initialize table_head structures, I'm trying to keep this structure as |
290 | * opaque as possible. |
291 | */ |
292 | void |
293 | dm_table_head_init(dm_table_head_t * head) |
294 | { |
295 | head->cur_active_table = 0; |
296 | head->io_cnt = 0; |
297 | |
298 | /* Initialize tables. */ |
299 | SLIST_INIT(&head->tables[0]); |
300 | SLIST_INIT(&head->tables[1]); |
301 | |
302 | mutex_init(&head->table_mtx, MUTEX_DEFAULT, IPL_NONE); |
303 | cv_init(&head->table_cv, "dm_io" ); |
304 | } |
305 | /* |
306 | * Destroy all variables in table_head |
307 | */ |
308 | void |
309 | dm_table_head_destroy(dm_table_head_t * head) |
310 | { |
311 | KASSERT(!mutex_owned(&head->table_mtx)); |
312 | KASSERT(!cv_has_waiters(&head->table_cv)); |
313 | /* tables doens't exists when I call this routine, therefore it |
314 | * doesn't make sense to have io_cnt != 0 */ |
315 | KASSERT(head->io_cnt == 0); |
316 | |
317 | cv_destroy(&head->table_cv); |
318 | mutex_destroy(&head->table_mtx); |
319 | } |
320 | |