1 /* $NetBSD: dm_pdev.c,v 1.21 2019/12/15 14:39:42 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 1.21 2019/12/15 14:39:42 tkusumi 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 * 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 * 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 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 { 142 143 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 kmem_free(dmp, sizeof(*dmp)); 179 return error; 180 } 181 } 182 kmem_free(dmp, sizeof(*dmp)); 183 184 return 0; 185 } 186 187 /* 188 * Destroy all existing pdev's in device-mapper. 189 */ 190 int 191 dm_pdev_destroy(void) 192 { 193 dm_pdev_t *dmp; 194 195 mutex_enter(&dm_pdev_mutex); 196 197 while ((dmp = SLIST_FIRST(&dm_pdev_list)) != NULL) { 198 SLIST_REMOVE(&dm_pdev_list, dmp, dm_pdev, next_pdev); 199 dm_pdev_rem(dmp); 200 } 201 KASSERT(SLIST_EMPTY(&dm_pdev_list)); 202 203 mutex_exit(&dm_pdev_mutex); 204 205 mutex_destroy(&dm_pdev_mutex); 206 return 0; 207 } 208 209 /* 210 * This funcion is called from dm_dev_remove_ioctl. 211 * When I'm removing device from list, I have to decrement 212 * reference counter. If reference counter is 0 I will remove 213 * dmp from global list and from device list to. And I will CLOSE 214 * dmp vnode too. 215 */ 216 217 /* 218 * Decrement pdev reference counter if 0 remove it. 219 */ 220 int 221 dm_pdev_decr(dm_pdev_t *dmp) 222 { 223 224 KASSERT(dmp != NULL); 225 /* 226 * If this was last reference remove dmp from 227 * global list also. 228 */ 229 mutex_enter(&dm_pdev_mutex); 230 231 if (--dmp->ref_cnt == 0) { 232 SLIST_REMOVE(&dm_pdev_list, dmp, dm_pdev, next_pdev); 233 mutex_exit(&dm_pdev_mutex); 234 dm_pdev_rem(dmp); 235 return 0; 236 } 237 238 mutex_exit(&dm_pdev_mutex); 239 return 0; 240 } 241 242 #if 0 243 static int 244 dm_pdev_dump_list(void) 245 { 246 dm_pdev_t *dmp; 247 248 aprint_verbose("Dumping dm_pdev_list\n"); 249 250 SLIST_FOREACH(dmp, &dm_pdev_list, next_pdev) { 251 aprint_verbose("dm_pdev_name %s ref_cnt %d list_rf_cnt %d\n", 252 dmp->name, dmp->ref_cnt, dmp->list_ref_cnt); 253 } 254 255 return 0; 256 } 257 #endif 258