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dm_target_zero.c revision 1.1.2.4 
      1 /*
      2  * Copyright (c) 1996, 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
      3  * All rights reserved.
      4  *
      5  * This code is derived from software contributed to The NetBSD Foundation
      6  * by Adam Hamsik.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     27  * POSSIBILITY OF SUCH DAMAGE.
     28  */
     29 
     30 
     31 /*
     32  * This file implements initial version of device-mapper zero target.
     33  */
     34 #include <sys/types.h>
     35 #include <sys/param.h>
     36 
     37 #include <sys/buf.h>
     38 #include <sys/errno.h>
     39 #include <sys/ioctl.h>
     40 #include <sys/ioccom.h>
     41 #include <sys/kmem.h>
     42 #include <sys/types.h>
     43 #include <sys/param.h>
     44 #include <sys/queue.h>
     45 
     46 #include "dm.h"
     47 
     48 /*
     49  * Zero target init function. This target doesn't need
     50  * target specific config area.
     51  */
     52 int
     53 dm_target_zero_init(struct dm_dev *dmv, void **target_config, char *argv)
     54 {
     55 
     56 	printf("Zero target init function called!!\n");
     57 
     58 	dmv->dev_type = DM_ZERO_DEV;
     59 
     60 	*target_config = NULL;
     61 
     62 	return 0;
     63 }
     64 
     65 /*
     66  * This routine does IO operations.
     67  */
     68 int
     69 dm_target_zero_strategy(struct dm_table_entry *table_en, struct buf *bp)
     70 {
     71 
     72 	printf("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; /* nestiobuf_done wants b_resid = 0 to be sure
     76 			    that there is no other io to done  */
     77 
     78 	biodone(bp);
     79 
     80 	return 0;
     81 }
     82 
     83 /* Doesn't not need to do anything here. */
     84 int
     85 dm_target_zero_destroy(struct dm_table_entry *table_en)
     86 {
     87 	return 0;
     88 }
     89 
     90 /* Unsuported for this target. */
     91 int
     92 dm_target_zero_upcall(struct dm_table_entry *table_en, struct buf *bp)
     93 {
     94 	return 0;
     95 }
     96 
     97