1 /* $NetBSD: dm_pdev.c,v 1.10 2018/01/05 14:22:26 christos 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 1.10 2018/01/05 14:22:26 christos Exp $"); 33 34 #include <sys/types.h> 35 #include <sys/param.h> 36 37 #include <sys/disk.h> 38 #include <sys/fcntl.h> 39 #include <sys/kmem.h> 40 #include <sys/namei.h> 41 #include <sys/vnode.h> 42 43 #include <dev/dkvar.h> 44 45 #include "dm.h" 46 47 SLIST_HEAD(dm_pdevs, dm_pdev) dm_pdev_list; 48 49 kmutex_t dm_pdev_mutex; 50 51 static dm_pdev_t *dm_pdev_alloc(const char *); 52 static int dm_pdev_rem(dm_pdev_t *); 53 static dm_pdev_t *dm_pdev_lookup_name(const char *); 54 55 /* 56 * Find used pdev with name == dm_pdev_name. 57 */ 58 dm_pdev_t * 59 dm_pdev_lookup_name(const char *dm_pdev_name) 60 { 61 dm_pdev_t *dm_pdev; 62 size_t dlen; 63 size_t slen; 64 65 KASSERT(dm_pdev_name != NULL); 66 67 slen = strlen(dm_pdev_name); 68 69 SLIST_FOREACH(dm_pdev, &dm_pdev_list, next_pdev) { 70 dlen = strlen(dm_pdev->name); 71 72 if (slen != dlen) 73 continue; 74 75 if (strncmp(dm_pdev_name, dm_pdev->name, slen) == 0) 76 return dm_pdev; 77 } 78 79 return NULL; 80 } 81 82 /* 83 * Create entry for device with name dev_name and open vnode for it. 84 * If entry already exists in global SLIST I will only increment 85 * reference counter. 86 */ 87 dm_pdev_t * 88 dm_pdev_insert(const char *dev_name) 89 { 90 struct pathbuf *dev_pb; 91 dm_pdev_t *dmp; 92 int error; 93 94 KASSERT(dev_name != NULL); 95 96 mutex_enter(&dm_pdev_mutex); 97 dmp = dm_pdev_lookup_name(dev_name); 98 99 if (dmp != NULL) { 100 dmp->ref_cnt++; 101 aprint_debug("%s: pdev %s already in tree\n", 102 __func__, dev_name); 103 mutex_exit(&dm_pdev_mutex); 104 return dmp; 105 } 106 mutex_exit(&dm_pdev_mutex); 107 108 if ((dmp = dm_pdev_alloc(dev_name)) == NULL) 109 return NULL; 110 111 dev_pb = pathbuf_create(dev_name); 112 if (dev_pb == NULL) { 113 aprint_debug("%s: pathbuf_create on device: %s failed!\n", 114 __func__, dev_name); 115 kmem_free(dmp, sizeof(dm_pdev_t)); 116 return NULL; 117 } 118 error = dk_lookup(dev_pb, curlwp, &dmp->pdev_vnode); 119 pathbuf_destroy(dev_pb); 120 if (error) { 121 aprint_debug("%s: dk_lookup on device: %s (error %d)\n", 122 __func__, dev_name, error); 123 kmem_free(dmp, sizeof(dm_pdev_t)); 124 return NULL; 125 } 126 getdisksize(dmp->pdev_vnode, &dmp->pdev_numsec, &dmp->pdev_secsize); 127 dmp->ref_cnt = 1; 128 129 mutex_enter(&dm_pdev_mutex); 130 SLIST_INSERT_HEAD(&dm_pdev_list, dmp, next_pdev); 131 mutex_exit(&dm_pdev_mutex); 132 133 return dmp; 134 } 135 136 /* 137 * Initialize pdev subsystem. 138 */ 139 int 140 dm_pdev_init(void) 141 { 142 SLIST_INIT(&dm_pdev_list); /* initialize global pdev list */ 143 mutex_init(&dm_pdev_mutex, MUTEX_DEFAULT, IPL_NONE); 144 145 return 0; 146 } 147 148 /* 149 * Allocat new pdev structure if is not already present and 150 * set name. 151 */ 152 static dm_pdev_t * 153 dm_pdev_alloc(const char *name) 154 { 155 dm_pdev_t *dmp; 156 157 dmp = kmem_zalloc(sizeof(*dmp), KM_SLEEP); 158 strlcpy(dmp->name, name, sizeof(dmp->name)); 159 dmp->ref_cnt = 0; 160 dmp->pdev_vnode = NULL; 161 162 return dmp; 163 } 164 165 /* 166 * Destroy allocated dm_pdev. 167 */ 168 static int 169 dm_pdev_rem(dm_pdev_t * dmp) 170 { 171 172 KASSERT(dmp != NULL); 173 174 if (dmp->pdev_vnode != NULL) { 175 int error = vn_close(dmp->pdev_vnode, FREAD | FWRITE, FSCRED); 176 if (error != 0) 177 return error; 178 } 179 kmem_free(dmp, sizeof(*dmp)); 180 181 return 0; 182 } 183 184 /* 185 * Destroy all existing pdev's in device-mapper. 186 */ 187 int 188 dm_pdev_destroy(void) 189 { 190 dm_pdev_t *dm_pdev; 191 192 mutex_enter(&dm_pdev_mutex); 193 while (!SLIST_EMPTY(&dm_pdev_list)) { /* List Deletion. */ 194 195 dm_pdev = SLIST_FIRST(&dm_pdev_list); 196 197 SLIST_REMOVE_HEAD(&dm_pdev_list, next_pdev); 198 199 dm_pdev_rem(dm_pdev); 200 } 201 mutex_exit(&dm_pdev_mutex); 202 203 mutex_destroy(&dm_pdev_mutex); 204 return 0; 205 } 206 207 /* 208 * This funcion is called from dm_dev_remove_ioctl. 209 * When I'm removing device from list, I have to decrement 210 * reference counter. If reference counter is 0 I will remove 211 * dmp from global list and from device list to. And I will CLOSE 212 * dmp vnode too. 213 */ 214 215 /* 216 * Decrement pdev reference counter if 0 remove it. 217 */ 218 int 219 dm_pdev_decr(dm_pdev_t * dmp) 220 { 221 KASSERT(dmp != NULL); 222 /* 223 * If this was last reference remove dmp from 224 * global list also. 225 */ 226 mutex_enter(&dm_pdev_mutex); 227 228 if (--dmp->ref_cnt == 0) { 229 SLIST_REMOVE(&dm_pdev_list, dmp, dm_pdev, next_pdev); 230 mutex_exit(&dm_pdev_mutex); 231 dm_pdev_rem(dmp); 232 return 0; 233 } 234 mutex_exit(&dm_pdev_mutex); 235 return 0; 236 } 237 238 #if 0 239 static int 240 dm_pdev_dump_list(void) 241 { 242 dm_pdev_t *dmp; 243 244 aprint_verbose("Dumping dm_pdev_list\n"); 245 246 SLIST_FOREACH(dmp, &dm_pdev_list, next_pdev) { 247 aprint_verbose("dm_pdev_name %s ref_cnt %d list_rf_cnt %d\n", 248 dmp->name, dmp->ref_cnt, dmp->list_ref_cnt); 249 } 250 251 return 0; 252 253 } 254 #endif 255