1 /* $NetBSD: dm_pdev.c,v 1.23 2021/08/21 22:23:33 andvar 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 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: dm_pdev.c,v 1.23 2021/08/21 22:23:33 andvar Exp $");
33
34 #include <sys/types.h>
35 #include <sys/param.h>
36 #include <sys/disk.h>
37 #include <sys/fcntl.h>
38 #include <sys/kmem.h>
39 #include <sys/namei.h>
40
41 #include <dev/dkvar.h>
42
43 #include "dm.h"
44
45 static SLIST_HEAD(dm_pdevs, dm_pdev) dm_pdev_list;
46
47 static kmutex_t dm_pdev_mutex;
48
49 static dm_pdev_t *dm_pdev_alloc(const char *);
50 static int dm_pdev_rem(dm_pdev_t *);
51 static dm_pdev_t *dm_pdev_lookup_name(const char *);
52
53 /*
54 * Find used pdev with name == dm_pdev_name.
55 */
56 dm_pdev_t *
dm_pdev_lookup_name(const char * dm_pdev_name)57 dm_pdev_lookup_name(const char *dm_pdev_name)
58 {
59 dm_pdev_t *dm_pdev;
60 size_t dlen;
61 size_t slen;
62
63 KASSERT(dm_pdev_name != NULL);
64
65 slen = strlen(dm_pdev_name);
66
67 SLIST_FOREACH(dm_pdev, &dm_pdev_list, next_pdev) {
68 dlen = strlen(dm_pdev->name);
69
70 if (slen != dlen)
71 continue;
72
73 if (strncmp(dm_pdev_name, dm_pdev->name, slen) == 0)
74 return dm_pdev;
75 }
76
77 return NULL;
78 }
79
80 /*
81 * Create entry for device with name dev_name and open vnode for it.
82 * If entry already exists in global SLIST I will only increment
83 * reference counter.
84 */
85 dm_pdev_t *
dm_pdev_insert(const char * dev_name)86 dm_pdev_insert(const char *dev_name)
87 {
88 struct pathbuf *dev_pb;
89 dm_pdev_t *dmp;
90 int error;
91
92 KASSERT(dev_name != NULL);
93
94 mutex_enter(&dm_pdev_mutex);
95 dmp = dm_pdev_lookup_name(dev_name);
96
97 if (dmp != NULL) {
98 dmp->ref_cnt++;
99 aprint_debug("%s: pdev %s already in tree\n",
100 __func__, dev_name);
101 mutex_exit(&dm_pdev_mutex);
102 return dmp;
103 }
104
105 if ((dmp = dm_pdev_alloc(dev_name)) == NULL) {
106 mutex_exit(&dm_pdev_mutex);
107 return NULL;
108 }
109
110 dev_pb = pathbuf_create(dev_name);
111 if (dev_pb == NULL) {
112 aprint_debug("%s: pathbuf_create on device: %s failed!\n",
113 __func__, dev_name);
114 mutex_exit(&dm_pdev_mutex);
115 kmem_free(dmp, sizeof(dm_pdev_t));
116 return NULL;
117 }
118 error = vn_bdev_openpath(dev_pb, &dmp->pdev_vnode, curlwp);
119 pathbuf_destroy(dev_pb);
120 if (error) {
121 aprint_debug("%s: lookup on device: %s (error %d)\n",
122 __func__, dev_name, error);
123 mutex_exit(&dm_pdev_mutex);
124 kmem_free(dmp, sizeof(dm_pdev_t));
125 return NULL;
126 }
127 getdisksize(dmp->pdev_vnode, &dmp->pdev_numsec, &dmp->pdev_secsize);
128 dmp->ref_cnt = 1;
129
130 snprintf(dmp->udev_name, sizeof(dmp->udev_name), "%d:%d",
131 major(dmp->pdev_vnode->v_rdev), minor(dmp->pdev_vnode->v_rdev));
132 aprint_debug("%s: %s %s\n", __func__, dev_name, dmp->udev_name);
133
134 SLIST_INSERT_HEAD(&dm_pdev_list, dmp, next_pdev);
135 mutex_exit(&dm_pdev_mutex);
136
137 return dmp;
138 }
139
140 /*
141 * Initialize pdev subsystem.
142 */
143 int
dm_pdev_init(void)144 dm_pdev_init(void)
145 {
146
147 SLIST_INIT(&dm_pdev_list); /* initialize global pdev list */
148 mutex_init(&dm_pdev_mutex, MUTEX_DEFAULT, IPL_NONE);
149
150 return 0;
151 }
152
153 /*
154 * Allocat new pdev structure if is not already present and
155 * set name.
156 */
157 static dm_pdev_t *
dm_pdev_alloc(const char * name)158 dm_pdev_alloc(const char *name)
159 {
160 dm_pdev_t *dmp;
161
162 dmp = kmem_zalloc(sizeof(*dmp), KM_SLEEP);
163 strlcpy(dmp->name, name, sizeof(dmp->name));
164 dmp->ref_cnt = 0;
165 dmp->pdev_vnode = NULL;
166
167 return dmp;
168 }
169
170 /*
171 * Destroy allocated dm_pdev.
172 */
173 static int
dm_pdev_rem(dm_pdev_t * dmp)174 dm_pdev_rem(dm_pdev_t *dmp)
175 {
176
177 KASSERT(dmp != NULL);
178
179 if (dmp->pdev_vnode != NULL) {
180 int error = vn_close(dmp->pdev_vnode, FREAD | FWRITE, FSCRED);
181 if (error != 0) {
182 kmem_free(dmp, sizeof(*dmp));
183 return error;
184 }
185 }
186 kmem_free(dmp, sizeof(*dmp));
187
188 return 0;
189 }
190
191 /*
192 * Destroy all existing pdev's in device-mapper.
193 */
194 int
dm_pdev_destroy(void)195 dm_pdev_destroy(void)
196 {
197 dm_pdev_t *dmp;
198
199 mutex_enter(&dm_pdev_mutex);
200
201 while ((dmp = SLIST_FIRST(&dm_pdev_list)) != NULL) {
202 SLIST_REMOVE(&dm_pdev_list, dmp, dm_pdev, next_pdev);
203 dm_pdev_rem(dmp);
204 }
205 KASSERT(SLIST_EMPTY(&dm_pdev_list));
206
207 mutex_exit(&dm_pdev_mutex);
208
209 mutex_destroy(&dm_pdev_mutex);
210 return 0;
211 }
212
213 /*
214 * This function is called from dm_dev_remove_ioctl.
215 * When I'm removing device from list, I have to decrement
216 * reference counter. If reference counter is 0 I will remove
217 * dmp from global list and from device list to. And I will CLOSE
218 * dmp vnode too.
219 */
220
221 /*
222 * Decrement pdev reference counter if 0 remove it.
223 */
224 int
dm_pdev_decr(dm_pdev_t * dmp)225 dm_pdev_decr(dm_pdev_t *dmp)
226 {
227
228 KASSERT(dmp != NULL);
229 /*
230 * If this was last reference remove dmp from
231 * global list also.
232 */
233 mutex_enter(&dm_pdev_mutex);
234
235 if (--dmp->ref_cnt == 0) {
236 SLIST_REMOVE(&dm_pdev_list, dmp, dm_pdev, next_pdev);
237 mutex_exit(&dm_pdev_mutex);
238 dm_pdev_rem(dmp);
239 return 0;
240 }
241
242 mutex_exit(&dm_pdev_mutex);
243 return 0;
244 }
245
246 #if 0
247 static int
248 dm_pdev_dump_list(void)
249 {
250 dm_pdev_t *dmp;
251
252 aprint_verbose("Dumping dm_pdev_list\n");
253
254 SLIST_FOREACH(dmp, &dm_pdev_list, next_pdev) {
255 aprint_verbose("dm_pdev_name %s ref_cnt %d list_rf_cnt %d\n",
256 dmp->name, dmp->ref_cnt, dmp->list_ref_cnt);
257 }
258
259 return 0;
260 }
261 #endif
262