Release 4.12 drivers/md/dm-zero.c
/*
* Copyright (C) 2003 Jana Saout <jana@saout.de>
*
* This file is released under the GPL.
*/
#include <linux/device-mapper.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bio.h>
#define DM_MSG_PREFIX "zero"
/*
* Construct a dummy mapping that only returns zeros
*/
static int zero_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
if (argc != 0) {
ti->error = "No arguments required";
return -EINVAL;
}
/*
* Silently drop discards, avoiding -EOPNOTSUPP.
*/
ti->num_discard_bios = 1;
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Alasdair G. Kergon | 42 | 87.50% | 3 | 75.00% |
| Mike Snitzer | 6 | 12.50% | 1 | 25.00% |
| Total | 48 | 100.00% | 4 | 100.00% |
/*
* Return zeros only on reads
*/
static int zero_map(struct dm_target *ti, struct bio *bio)
{
switch (bio_op(bio)) {
case REQ_OP_READ:
if (bio->bi_opf & REQ_RAHEAD) {
/* readahead of null bytes only wastes buffer cache */
return -EIO;
}
zero_fill_bio(bio);
break;
case REQ_OP_WRITE:
/* writes get silently dropped */
break;
default:
return -EIO;
}
bio_endio(bio);
/* accepted bio, don't make new request */
return DM_MAPIO_SUBMITTED;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Alasdair G. Kergon | 46 | 67.65% | 1 | 25.00% |
| Christoph Hellwig | 20 | 29.41% | 1 | 25.00% |
| Kiyoshi Ueda | 1 | 1.47% | 1 | 25.00% |
| Jens Axboe | 1 | 1.47% | 1 | 25.00% |
| Total | 68 | 100.00% | 4 | 100.00% |
static struct target_type zero_target = {
.name = "zero",
.version = {1, 1, 0},
.module = THIS_MODULE,
.ctr = zero_ctr,
.map = zero_map,
};
static int __init dm_zero_init(void)
{
int r = dm_register_target(&zero_target);
if (r < 0)
DMERR("register failed %d", r);
return r;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Alasdair G. Kergon | 34 | 100.00% | 3 | 100.00% |
| Total | 34 | 100.00% | 3 | 100.00% |
static void __exit dm_zero_exit(void)
{
dm_unregister_target(&zero_target);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Alasdair G. Kergon | 15 | 100.00% | 2 | 100.00% |
| Total | 15 | 100.00% | 2 | 100.00% |
module_init(dm_zero_init)
module_exit(dm_zero_exit)
MODULE_AUTHOR("Jana Saout <jana@saout.de>");
MODULE_DESCRIPTION(DM_NAME " dummy target returning zeros");
MODULE_LICENSE("GPL");
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Alasdair G. Kergon | 204 | 82.93% | 4 | 33.33% |
| Christoph Hellwig | 20 | 8.13% | 1 | 8.33% |
| Kevin Corry | 10 | 4.07% | 1 | 8.33% |
| Mike Snitzer | 6 | 2.44% | 1 | 8.33% |
| Mikulas Patocka | 2 | 0.81% | 2 | 16.67% |
| Jana Saout | 2 | 0.81% | 1 | 8.33% |
| Kiyoshi Ueda | 1 | 0.41% | 1 | 8.33% |
| Jens Axboe | 1 | 0.41% | 1 | 8.33% |
| Total | 246 | 100.00% | 12 | 100.00% |
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