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