1 /* $NetBSD: dm_target_zero.c,v 1.13 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_target_zero.c,v 1.13 2018/01/05 14:22:26 christos Exp $"); 33 34 /* 35 * This file implements initial version of device-mapper zero target. 36 */ 37 #include <sys/types.h> 38 #include <sys/param.h> 39 40 #include <sys/buf.h> 41 42 #include "dm.h" 43 44 /* dm_target_zero.c */ 45 int dm_target_zero_init(dm_dev_t *, void**, char *); 46 char * dm_target_zero_status(void *); 47 int dm_target_zero_strategy(dm_table_entry_t *, struct buf *); 48 int dm_target_zero_sync(dm_table_entry_t *); 49 int dm_target_zero_destroy(dm_table_entry_t *); 50 int dm_target_zero_deps(dm_table_entry_t *, prop_array_t); 51 int dm_target_zero_upcall(dm_table_entry_t *, struct buf *); 52 53 #ifdef DM_TARGET_MODULE 54 /* 55 * Every target can be compiled directly to dm driver or as a 56 * separate module this part of target is used for loading targets 57 * to dm driver. 58 * Target can be unloaded from kernel only if there are no users of 59 * it e.g. there are no devices which uses that target. 60 */ 61 #include <sys/kernel.h> 62 #include <sys/module.h> 63 64 MODULE(MODULE_CLASS_MISC, dm_target_zero, "dm"); 65 66 static int 67 dm_target_zero_modcmd(modcmd_t cmd, void *arg) 68 { 69 dm_target_t *dmt; 70 int r; 71 dmt = NULL; 72 73 switch (cmd) { 74 case MODULE_CMD_INIT: 75 if ((dmt = dm_target_lookup("zero")) != NULL) { 76 dm_target_unbusy(dmt); 77 return EEXIST; 78 } 79 dmt = dm_target_alloc("zero"); 80 81 dmt->version[0] = 1; 82 dmt->version[1] = 0; 83 dmt->version[2] = 0; 84 strlcpy(dmt->name, "zero", DM_MAX_TYPE_NAME); 85 dmt->init = &dm_target_zero_init; 86 dmt->status = &dm_target_zero_status; 87 dmt->strategy = &dm_target_zero_strategy; 88 dmt->sync = &dm_target_zero_sync; 89 dmt->deps = &dm_target_zero_deps; 90 dmt->destroy = &dm_target_zero_destroy; 91 dmt->upcall = &dm_target_zero_upcall; 92 93 r = dm_target_insert(dmt); 94 break; 95 96 case MODULE_CMD_FINI: 97 r = dm_target_rem("zero"); 98 99 break; 100 101 case MODULE_CMD_STAT: 102 return ENOTTY; 103 104 default: 105 return ENOTTY; 106 } 107 108 return r; 109 } 110 #endif 111 112 /* 113 * Zero target init function. This target doesn't need 114 * target specific config area. 115 */ 116 int 117 dm_target_zero_init(dm_dev_t * dmv, void **target_config, char *argv) 118 { 119 120 printf("Zero target init function called!!\n"); 121 122 dmv->dev_type = DM_ZERO_DEV; 123 124 *target_config = NULL; 125 126 return 0; 127 } 128 129 /* Status routine called to get params string. */ 130 char * 131 dm_target_zero_status(void *target_config) 132 { 133 return NULL; 134 } 135 136 137 /* 138 * This routine does IO operations. 139 */ 140 int 141 dm_target_zero_strategy(dm_table_entry_t * table_en, struct buf * bp) 142 { 143 144 /* printf("Zero target read function called %d!!\n", bp->b_bcount); */ 145 146 memset(bp->b_data, 0, bp->b_bcount); 147 bp->b_resid = 0; /* nestiobuf_done wants b_resid = 0 to be sure 148 * that there is no other io to done */ 149 150 biodone(bp); 151 152 return 0; 153 } 154 155 /* Sync underlying disk caches. */ 156 int 157 dm_target_zero_sync(dm_table_entry_t * table_en) 158 { 159 160 return 0; 161 } 162 163 /* Does not need to do anything here. */ 164 int 165 dm_target_zero_destroy(dm_table_entry_t * table_en) 166 { 167 table_en->target_config = NULL; 168 169 /* Unbusy target so we can unload it */ 170 dm_target_unbusy(table_en->target); 171 172 return 0; 173 } 174 175 /* Does not need to do anything here. */ 176 int 177 dm_target_zero_deps(dm_table_entry_t * table_en, prop_array_t prop_array) 178 { 179 return 0; 180 } 181 182 /* Unsuported for this target. */ 183 int 184 dm_target_zero_upcall(dm_table_entry_t * table_en, struct buf * bp) 185 { 186 return 0; 187 } 188