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dm_target_zero.c revision 1.1.2.1 
      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,
     54 	       	int argc, const char **argv)
     55 {
     56 
     57 	printf("Zero target init function called!!\n");
     58 
     59 	*target_config = NULL;
     60 
     61 	return 0;
     62 }
     63 
     64 /*
     65  * This routine does IO operations.
     66  */
     67 int
     68 dm_target_zero_strategy(struct dm_table_entry *table_en, struct buf *bp)
     69 {
     70 
     71 	printf("Zero target read function called %d!!\n",bp->b_bcount);
     72 
     73 	memset(bp->b_data, 0, bp->b_bcount);
     74 	bp->b_resid = 0; /* nestiobuf_done wants b_resid = 0 to be sure
     75 			    that there is no other io to done  */
     76 
     77 	biodone(bp);
     78 
     79 	return 0;
     80 }
     81 
     82 /* Doesn't not need to do anything here. */
     83 int
     84 dm_target_zero_destroy(struct dm_table_entry *table_en)
     85 {
     86 	return 0;
     87 }
     88 
     89 /* Unsuported for this target. */
     90 int
     91 dm_target_zero_upcall(struct dm_table_entry *table_en, struct buf *bp)
     92 {
     93 	return 0;
     94 }
     95 
     96