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 * This file implements initial version of device-mapper zero target. 34 */ 35 #include <dev/disk/dm/dm.h> 36 37 /* 38 * Zero target init function. This target doesn't need 39 * target specific config area. 40 */ 41 static int 42 dm_target_zero_init(dm_table_entry_t *table_en, int argc, char **argv) 43 { 44 45 kprintf("Zero target init function called!!\n"); 46 47 dm_table_init_target(table_en, DM_ZERO_DEV, NULL); 48 49 return 0; 50 } 51 52 /* 53 * This routine does IO operations. 54 */ 55 static int 56 dm_target_zero_strategy(dm_table_entry_t *table_en, struct buf *bp) 57 { 58 59 /* kprintf("Zero target read function called %d!!\n", bp->b_bcount); */ 60 61 memset(bp->b_data, 0, bp->b_bcount); 62 bp->b_resid = 0; 63 biodone(&bp->b_bio1); 64 65 return 0; 66 } 67 68 /* Doesn't not need to do anything here. */ 69 static int 70 dm_target_zero_destroy(dm_table_entry_t *table_en) 71 { 72 return 0; 73 } 74 75 static int 76 dmtz_mod_handler(module_t mod, int type, void *unused) 77 { 78 dm_target_t *dmt = NULL; 79 int err = 0; 80 81 switch(type) { 82 case MOD_LOAD: 83 if ((dmt = dm_target_lookup("zero")) != NULL) { 84 dm_target_unbusy(dmt); 85 return EEXIST; 86 } 87 dmt = dm_target_alloc("zero"); 88 dmt->version[0] = 1; 89 dmt->version[1] = 0; 90 dmt->version[2] = 0; 91 dmt->init = &dm_target_zero_init; 92 dmt->destroy = &dm_target_zero_destroy; 93 dmt->strategy = &dm_target_zero_strategy; 94 95 err = dm_target_insert(dmt); 96 if (err == 0) 97 kprintf("dm_target_zero: Successfully initialized\n"); 98 break; 99 100 case MOD_UNLOAD: 101 err = dm_target_remove("zero"); 102 if (err == 0) 103 kprintf("dm_target_zero: unloaded\n"); 104 break; 105 106 default: 107 break; 108 } 109 110 return err; 111 } 112 113 DM_TARGET_BUILTIN(dm_target_zero, dmtz_mod_handler); 114