1 /* $NetBSD: dm_pdev.c,v 1.18 2019/12/07 15:28:39 tkusumi 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 1.18 2019/12/07 15:28:39 tkusumi 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 42 #include <dev/dkvar.h> 43 44 #include "dm.h" 45 46 static SLIST_HEAD(dm_pdevs, dm_pdev) dm_pdev_list; 47 48 static kmutex_t dm_pdev_mutex; 49 50 static dm_pdev_t *dm_pdev_alloc(const char *); 51 static int dm_pdev_rem(dm_pdev_t *); 52 static dm_pdev_t *dm_pdev_lookup_name(const char *); 53 54 /* 55 * Find used pdev with name == dm_pdev_name. 56 */ 57 dm_pdev_t * 58 dm_pdev_lookup_name(const char *dm_pdev_name) 59 { 60 dm_pdev_t *dm_pdev; 61 size_t dlen; 62 size_t slen; 63 64 KASSERT(dm_pdev_name != NULL); 65 66 slen = strlen(dm_pdev_name); 67 68 SLIST_FOREACH(dm_pdev, &dm_pdev_list, next_pdev) { 69 dlen = strlen(dm_pdev->name); 70 71 if (slen != dlen) 72 continue; 73 74 if (strncmp(dm_pdev_name, dm_pdev->name, slen) == 0) 75 return dm_pdev; 76 } 77 78 return NULL; 79 } 80 81 /* 82 * Create entry for device with name dev_name and open vnode for it. 83 * If entry already exists in global SLIST I will only increment 84 * reference counter. 85 */ 86 dm_pdev_t * 87 dm_pdev_insert(const char *dev_name) 88 { 89 struct pathbuf *dev_pb; 90 dm_pdev_t *dmp; 91 int error; 92 93 KASSERT(dev_name != NULL); 94 95 mutex_enter(&dm_pdev_mutex); 96 dmp = dm_pdev_lookup_name(dev_name); 97 98 if (dmp != NULL) { 99 dmp->ref_cnt++; 100 aprint_debug("%s: pdev %s already in tree\n", 101 __func__, dev_name); 102 mutex_exit(&dm_pdev_mutex); 103 return dmp; 104 } 105 106 if ((dmp = dm_pdev_alloc(dev_name)) == NULL) { 107 mutex_exit(&dm_pdev_mutex); 108 return NULL; 109 } 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 mutex_exit(&dm_pdev_mutex); 116 kmem_free(dmp, sizeof(dm_pdev_t)); 117 return NULL; 118 } 119 error = dk_lookup(dev_pb, curlwp, &dmp->pdev_vnode); 120 pathbuf_destroy(dev_pb); 121 if (error) { 122 aprint_debug("%s: dk_lookup on device: %s (error %d)\n", 123 __func__, dev_name, error); 124 mutex_exit(&dm_pdev_mutex); 125 kmem_free(dmp, sizeof(dm_pdev_t)); 126 return NULL; 127 } 128 getdisksize(dmp->pdev_vnode, &dmp->pdev_numsec, &dmp->pdev_secsize); 129 dmp->ref_cnt = 1; 130 131 SLIST_INSERT_HEAD(&dm_pdev_list, dmp, next_pdev); 132 mutex_exit(&dm_pdev_mutex); 133 134 return dmp; 135 } 136 137 /* 138 * Initialize pdev subsystem. 139 */ 140 int 141 dm_pdev_init(void) 142 { 143 SLIST_INIT(&dm_pdev_list); /* initialize global pdev list */ 144 mutex_init(&dm_pdev_mutex, MUTEX_DEFAULT, IPL_NONE); 145 146 return 0; 147 } 148 149 /* 150 * Allocat new pdev structure if is not already present and 151 * set name. 152 */ 153 static dm_pdev_t * 154 dm_pdev_alloc(const char *name) 155 { 156 dm_pdev_t *dmp; 157 158 dmp = kmem_zalloc(sizeof(*dmp), KM_SLEEP); 159 strlcpy(dmp->name, name, sizeof(dmp->name)); 160 dmp->ref_cnt = 0; 161 dmp->pdev_vnode = NULL; 162 163 return dmp; 164 } 165 166 /* 167 * Destroy allocated dm_pdev. 168 */ 169 static int 170 dm_pdev_rem(dm_pdev_t *dmp) 171 { 172 173 KASSERT(dmp != NULL); 174 175 if (dmp->pdev_vnode != NULL) { 176 int error = vn_close(dmp->pdev_vnode, FREAD | FWRITE, FSCRED); 177 if (error != 0) 178 return error; 179 } 180 kmem_free(dmp, sizeof(*dmp)); 181 182 return 0; 183 } 184 185 /* 186 * Destroy all existing pdev's in device-mapper. 187 */ 188 int 189 dm_pdev_destroy(void) 190 { 191 dm_pdev_t *dmp; 192 193 mutex_enter(&dm_pdev_mutex); 194 195 while ((dmp = SLIST_FIRST(&dm_pdev_list)) != NULL) { 196 SLIST_REMOVE(&dm_pdev_list, dmp, dm_pdev, next_pdev); 197 dm_pdev_rem(dmp); 198 } 199 KASSERT(SLIST_EMPTY(&dm_pdev_list)); 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 #endif 254