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 <dev/disk/dm/dm.h> 42 43 /* 44 * Zero target init function. This target doesn't need 45 * target specific config area. 46 */ 47 static int 48 dm_target_zero_init(dm_dev_t * dmv, void **target_config, char *argv) 49 { 50 51 kprintf("Zero target init function called!!\n"); 52 53 dmv->dev_type = DM_ZERO_DEV; 54 55 *target_config = NULL; 56 57 return 0; 58 } 59 60 /* Status routine called to get params string. */ 61 static char * 62 dm_target_zero_status(void *target_config) 63 { 64 return NULL; 65 } 66 67 68 /* 69 * This routine does IO operations. 70 */ 71 static int 72 dm_target_zero_strategy(dm_table_entry_t * table_en, struct buf * bp) 73 { 74 75 /* printf("Zero target read function called %d!!\n", bp->b_bcount); */ 76 77 memset(bp->b_data, 0, bp->b_bcount); 78 bp->b_resid = 0; 79 biodone(&bp->b_bio1); 80 81 return 0; 82 } 83 84 /* Doesn't not need to do anything here. */ 85 static int 86 dm_target_zero_destroy(dm_table_entry_t * table_en) 87 { 88 table_en->target_config = NULL; 89 90 /* Unbusy target so we can unload it */ 91 dm_target_unbusy(table_en->target); 92 93 return 0; 94 } 95 96 /* Doesn't not need to do anything here. */ 97 static int 98 dm_target_zero_deps(dm_table_entry_t * table_en, prop_array_t prop_array) 99 { 100 return 0; 101 } 102 /* Unsuported for this target. */ 103 static int 104 dm_target_zero_upcall(dm_table_entry_t * table_en, struct buf * bp) 105 { 106 return 0; 107 } 108 109 static int 110 dmtz_mod_handler(module_t mod, int type, void *unused) 111 { 112 dm_target_t *dmt = NULL; 113 int err = 0; 114 115 switch(type) { 116 case MOD_LOAD: 117 if ((dmt = dm_target_lookup("zero")) != NULL) { 118 dm_target_unbusy(dmt); 119 return EEXIST; 120 } 121 dmt = dm_target_alloc("zero"); 122 dmt->version[0] = 1; 123 dmt->version[1] = 0; 124 dmt->version[2] = 0; 125 strlcpy(dmt->name, "zero", DM_MAX_TYPE_NAME); 126 dmt->init = &dm_target_zero_init; 127 dmt->status = &dm_target_zero_status; 128 dmt->strategy = &dm_target_zero_strategy; 129 dmt->deps = &dm_target_zero_deps; 130 dmt->destroy = &dm_target_zero_destroy; 131 dmt->upcall = &dm_target_zero_upcall; 132 dmt->dump = NULL; 133 134 err = dm_target_insert(dmt); 135 if (err == 0) 136 kprintf("dm_target_zero: Successfully initialized\n"); 137 break; 138 139 case MOD_UNLOAD: 140 err = dm_target_rem("zero"); 141 if (err == 0) 142 kprintf("dm_target_zero: unloaded\n"); 143 break; 144 145 default: 146 break; 147 } 148 149 return err; 150 } 151 152 DM_TARGET_BUILTIN(dm_target_zero, dmtz_mod_handler); 153