1 /* $NetBSD: dm_target_zero.c,v 1.10 2010/01/04 00:12:22 haad 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 33 /* 34 * This file implements initial version of device-mapper zero target. 35 */ 36 #include <sys/types.h> 37 #include <sys/param.h> 38 39 #include <sys/buf.h> 40 41 #include "dm.h" 42 43 #ifdef DM_TARGET_MODULE 44 /* 45 * Every target can be compiled directly to dm driver or as a 46 * separate module this part of target is used for loading targets 47 * to dm driver. 48 * Target can be unloaded from kernel only if there are no users of 49 * it e.g. there are no devices which uses that target. 50 */ 51 #include <sys/kernel.h> 52 #include <sys/module.h> 53 54 MODULE(MODULE_CLASS_MISC, dm_target_zero, "dm"); 55 56 static int 57 dm_target_zero_modcmd(modcmd_t cmd, void *arg) 58 { 59 dm_target_t *dmt; 60 int r; 61 dmt = NULL; 62 63 switch (cmd) { 64 case MODULE_CMD_INIT: 65 if ((dmt = dm_target_lookup("zero")) != NULL) { 66 dm_target_unbusy(dmt); 67 return EEXIST; 68 } 69 dmt = dm_target_alloc("zero"); 70 71 dmt->version[0] = 1; 72 dmt->version[1] = 0; 73 dmt->version[2] = 0; 74 strlcpy(dmt->name, "zero", DM_MAX_TYPE_NAME); 75 dmt->init = &dm_target_zero_init; 76 dmt->status = &dm_target_zero_status; 77 dmt->strategy = &dm_target_zero_strategy; 78 dmt->deps = &dm_target_zero_deps; 79 dmt->destroy = &dm_target_zero_destroy; 80 dmt->upcall = &dm_target_zero_upcall; 81 82 r = dm_target_insert(dmt); 83 break; 84 85 case MODULE_CMD_FINI: 86 r = dm_target_rem("zero"); 87 88 break; 89 90 case MODULE_CMD_STAT: 91 return ENOTTY; 92 93 default: 94 return ENOTTY; 95 } 96 97 return r; 98 } 99 #endif 100 101 /* 102 * Zero target init function. This target doesn't need 103 * target specific config area. 104 */ 105 int 106 dm_target_zero_init(dm_dev_t * dmv, void **target_config, char *argv) 107 { 108 109 kprintf("Zero target init function called!!\n"); 110 111 dmv->dev_type = DM_ZERO_DEV; 112 113 *target_config = NULL; 114 115 return 0; 116 } 117 /* Status routine called to get params string. */ 118 char * 119 dm_target_zero_status(void *target_config) 120 { 121 return NULL; 122 } 123 124 125 /* 126 * This routine does IO operations. 127 */ 128 int 129 dm_target_zero_strategy(dm_table_entry_t * table_en, struct buf * bp) 130 { 131 132 /* printf("Zero target read function called %d!!\n", bp->b_bcount); */ 133 134 memset(bp->b_data, 0, bp->b_bcount); 135 bp->b_resid = 0; 136 biodone(&bp->b_bio1); 137 138 return 0; 139 } 140 /* Doesn't not need to do anything here. */ 141 int 142 dm_target_zero_destroy(dm_table_entry_t * table_en) 143 { 144 table_en->target_config = NULL; 145 146 /* Unbusy target so we can unload it */ 147 dm_target_unbusy(table_en->target); 148 149 return 0; 150 } 151 /* Doesn't not need to do anything here. */ 152 int 153 dm_target_zero_deps(dm_table_entry_t * table_en, prop_array_t prop_array) 154 { 155 return 0; 156 } 157 /* Unsuported for this target. */ 158 int 159 dm_target_zero_upcall(dm_table_entry_t * table_en, struct buf * bp) 160 { 161 return 0; 162 } 163