1 /* $NetBSD: dm_pdev.c,v 1.3 2009/03/18 10:22:39 cegger 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/disk.h> 36 #include <sys/fcntl.h> 37 #include <sys/kmem.h> 38 #include <sys/namei.h> 39 #include <sys/vnode.h> 40 41 #include <dev/dkvar.h> 42 43 #include "dm.h" 44 45 SLIST_HEAD(dm_pdevs, dm_pdev) dm_pdev_list; 46 47 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 int dlen; int slen; 61 62 KASSERT(dm_pdev_name != NULL); 63 64 slen = strlen(dm_pdev_name); 65 66 SLIST_FOREACH(dm_pdev, &dm_pdev_list, next_pdev) { 67 dlen = strlen(dm_pdev->name); 68 69 if (slen != dlen) 70 continue; 71 72 if (strncmp(dm_pdev_name, dm_pdev->name, slen) == 0) 73 return dm_pdev; 74 } 75 76 return NULL; 77 } 78 79 /* 80 * Create entry for device with name dev_name and open vnode for it. 81 * If entry already exists in global SLIST I will only increment 82 * reference counter. 83 */ 84 dm_pdev_t* 85 dm_pdev_insert(const char *dev_name) 86 { 87 dm_pdev_t *dmp; 88 int error; 89 90 KASSERT(dev_name != NULL); 91 92 mutex_enter(&dm_pdev_mutex); 93 dmp = dm_pdev_lookup_name(dev_name); 94 95 if (dmp != NULL) { 96 dmp->ref_cnt++; 97 aprint_verbose("dmp_pdev_insert pdev %s already in tree\n",dev_name); 98 mutex_exit(&dm_pdev_mutex); 99 return dmp; 100 } 101 mutex_exit(&dm_pdev_mutex); 102 103 if ((dmp = dm_pdev_alloc(dev_name)) == NULL) 104 return NULL; 105 106 error = dk_lookup(dev_name, curlwp, &dmp->pdev_vnode, UIO_SYSSPACE); 107 if (error) { 108 aprint_verbose("dk_lookup on device: %s failed with error %d!\n", 109 dev_name, error); 110 kmem_free(dmp, sizeof(dm_pdev_t)); 111 return NULL; 112 } 113 114 dmp->ref_cnt = 1; 115 116 mutex_enter(&dm_pdev_mutex); 117 SLIST_INSERT_HEAD(&dm_pdev_list, dmp, next_pdev); 118 mutex_exit(&dm_pdev_mutex); 119 120 return dmp; 121 } 122 123 /* 124 * Initialize pdev subsystem. 125 */ 126 int 127 dm_pdev_init(void) 128 { 129 SLIST_INIT(&dm_pdev_list); /* initialize global pdev list */ 130 mutex_init(&dm_pdev_mutex, MUTEX_DEFAULT, IPL_NONE); 131 132 return 0; 133 } 134 135 /* 136 * Allocat new pdev structure if is not already present and 137 * set name. 138 */ 139 static dm_pdev_t* 140 dm_pdev_alloc(const char *name) 141 { 142 dm_pdev_t *dmp; 143 144 if ((dmp = kmem_zalloc(sizeof(dm_pdev_t), KM_NOSLEEP)) == NULL) 145 return NULL; 146 147 strlcpy(dmp->name, name, MAX_DEV_NAME); 148 149 dmp->ref_cnt = 0; 150 dmp->pdev_vnode = NULL; 151 152 return dmp; 153 } 154 155 /* 156 * Destroy allocated dm_pdev. 157 */ 158 static int 159 dm_pdev_rem(dm_pdev_t *dmp) 160 { 161 int err; 162 163 KASSERT(dmp != NULL); 164 165 if (dmp->pdev_vnode != NULL) { 166 err = vn_close(dmp->pdev_vnode, FREAD | FWRITE, FSCRED); 167 if (err != 0) 168 return err; 169 } 170 171 kmem_free(dmp, sizeof(*dmp)); 172 dmp = NULL; 173 174 return 0; 175 } 176 177 /* 178 * Destroy all existing pdev's in device-mapper. 179 */ 180 int 181 dm_pdev_destroy(void) 182 { 183 dm_pdev_t *dm_pdev; 184 185 mutex_enter(&dm_pdev_mutex); 186 while (!SLIST_EMPTY(&dm_pdev_list)) { /* List Deletion. */ 187 188 dm_pdev = SLIST_FIRST(&dm_pdev_list); 189 190 SLIST_REMOVE_HEAD(&dm_pdev_list, next_pdev); 191 192 dm_pdev_rem(dm_pdev); 193 } 194 mutex_exit(&dm_pdev_mutex); 195 196 mutex_destroy(&dm_pdev_mutex); 197 return 0; 198 } 199 200 /* 201 * This funcion is called from dm_dev_remove_ioctl. 202 * When I'm removing device from list, I have to decrement 203 * reference counter. If reference counter is 0 I will remove 204 * dmp from global list and from device list to. And I will CLOSE 205 * dmp vnode too. 206 */ 207 208 /* 209 * Decrement pdev reference counter if 0 remove it. 210 */ 211 int 212 dm_pdev_decr(dm_pdev_t *dmp) 213 { 214 KASSERT(dmp != NULL); 215 /* 216 * If this was last reference remove dmp from 217 * global list also. 218 */ 219 mutex_enter(&dm_pdev_mutex); 220 221 if (--dmp->ref_cnt == 0) { 222 SLIST_REMOVE(&dm_pdev_list, dmp, dm_pdev, next_pdev); 223 mutex_exit(&dm_pdev_mutex); 224 dm_pdev_rem(dmp); 225 return 0; 226 } 227 228 mutex_exit(&dm_pdev_mutex); 229 return 0; 230 } 231 232 /*static int 233 dm_pdev_dump_list(void) 234 { 235 dm_pdev_t *dmp; 236 237 aprint_verbose("Dumping dm_pdev_list \n"); 238 239 SLIST_FOREACH(dmp, &dm_pdev_list, next_pdev) { 240 aprint_verbose("dm_pdev_name %s ref_cnt %d list_rf_cnt %d\n", 241 dmp->name, dmp->ref_cnt, dmp->list_ref_cnt); 242 } 243 244 return 0; 245 246 }*/ 247