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 38 #include <sys/buf.h> 39 40 #include <dev/disk/dm/dm.h> 41 42 /* 43 * Zero target init function. This target doesn't need 44 * target specific config area. 45 */ 46 static int 47 dm_target_zero_init(dm_dev_t *dmv, void **target_config, char *argv) 48 { 49 50 kprintf("Zero target init function called!!\n"); 51 52 dmv->dev_type = DM_ZERO_DEV; 53 54 *target_config = NULL; 55 56 return 0; 57 } 58 59 /* Table routine called to get params string. */ 60 static char * 61 dm_target_zero_table(void *target_config) 62 { 63 return NULL; 64 } 65 66 67 /* 68 * This routine does IO operations. 69 */ 70 static int 71 dm_target_zero_strategy(dm_table_entry_t *table_en, struct buf *bp) 72 { 73 74 /* kprintf("Zero target read function called %d!!\n", bp->b_bcount); */ 75 76 memset(bp->b_data, 0, bp->b_bcount); 77 bp->b_resid = 0; 78 biodone(&bp->b_bio1); 79 80 return 0; 81 } 82 83 /* Doesn't not need to do anything here. */ 84 static int 85 dm_target_zero_destroy(dm_table_entry_t *table_en) 86 { 87 table_en->target_config = NULL; 88 89 return 0; 90 } 91 92 /* Doesn't not need to do anything here. */ 93 static int 94 dm_target_zero_deps(dm_table_entry_t *table_en, prop_array_t prop_array) 95 { 96 return 0; 97 } 98 /* Unsuported for this target. */ 99 static int 100 dm_target_zero_upcall(dm_table_entry_t *table_en, struct buf *bp) 101 { 102 return 0; 103 } 104 105 static int 106 dmtz_mod_handler(module_t mod, int type, void *unused) 107 { 108 dm_target_t *dmt = NULL; 109 int err = 0; 110 111 switch(type) { 112 case MOD_LOAD: 113 if ((dmt = dm_target_lookup("zero")) != NULL) { 114 dm_target_unbusy(dmt); 115 return EEXIST; 116 } 117 dmt = dm_target_alloc("zero"); 118 dmt->version[0] = 1; 119 dmt->version[1] = 0; 120 dmt->version[2] = 0; 121 strlcpy(dmt->name, "zero", DM_MAX_TYPE_NAME); 122 dmt->init = &dm_target_zero_init; 123 dmt->table = &dm_target_zero_table; 124 dmt->strategy = &dm_target_zero_strategy; 125 dmt->deps = &dm_target_zero_deps; 126 dmt->destroy = &dm_target_zero_destroy; 127 dmt->upcall = &dm_target_zero_upcall; 128 dmt->dump = NULL; 129 130 err = dm_target_insert(dmt); 131 if (err == 0) 132 kprintf("dm_target_zero: Successfully initialized\n"); 133 break; 134 135 case MOD_UNLOAD: 136 err = dm_target_rem("zero"); 137 if (err == 0) 138 kprintf("dm_target_zero: unloaded\n"); 139 break; 140 141 default: 142 break; 143 } 144 145 return err; 146 } 147 148 DM_TARGET_BUILTIN(dm_target_zero, dmtz_mod_handler); 149