Merge branch 'akpm' (patches from Andrew)
[linux-2.6-block.git] / arch / s390 / hypfs / hypfs_dbfs.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
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2/*
3 * Hypervisor filesystem for Linux on s390 - debugfs interface
4 *
a53c8fab 5 * Copyright IBM Corp. 2010
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6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
7 */
8
9#include <linux/slab.h>
10#include "hypfs.h"
11
12static struct dentry *dbfs_dir;
13
14static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f)
15{
16 struct hypfs_dbfs_data *data;
17
18 data = kmalloc(sizeof(*data), GFP_KERNEL);
19 if (!data)
20 return NULL;
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21 data->dbfs_file = f;
22 return data;
23}
24
a178220d 25static void hypfs_dbfs_data_free(struct hypfs_dbfs_data *data)
2fcb3686 26{
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27 data->dbfs_file->data_free(data->buf_free_ptr);
28 kfree(data);
29}
30
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31static ssize_t dbfs_read(struct file *file, char __user *buf,
32 size_t size, loff_t *ppos)
33{
34 struct hypfs_dbfs_data *data;
35 struct hypfs_dbfs_file *df;
36 ssize_t rc;
37
38 if (*ppos != 0)
39 return 0;
40
496ad9aa 41 df = file_inode(file)->i_private;
2fcb3686 42 mutex_lock(&df->lock);
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43 data = hypfs_dbfs_data_alloc(df);
44 if (!data) {
45 mutex_unlock(&df->lock);
46 return -ENOMEM;
47 }
48 rc = df->data_create(&data->buf, &data->buf_free_ptr, &data->size);
49 if (rc) {
50 mutex_unlock(&df->lock);
51 kfree(data);
52 return rc;
2fcb3686 53 }
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54 mutex_unlock(&df->lock);
55
56 rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
a178220d 57 hypfs_dbfs_data_free(data);
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58 return rc;
59}
60
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61static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
62{
a455589f 63 struct hypfs_dbfs_file *df = file_inode(file)->i_private;
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64 long rc;
65
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66 mutex_lock(&df->lock);
67 if (df->unlocked_ioctl)
68 rc = df->unlocked_ioctl(file, cmd, arg);
69 else
70 rc = -ENOTTY;
71 mutex_unlock(&df->lock);
72 return rc;
73}
74
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75static const struct file_operations dbfs_ops = {
76 .read = dbfs_read,
77 .llseek = no_llseek,
07be0382 78 .unlocked_ioctl = dbfs_ioctl,
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79};
80
f36108c4 81void hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
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82{
83 df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df,
84 &dbfs_ops);
2fcb3686 85 mutex_init(&df->lock);
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86}
87
88void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
89{
90 debugfs_remove(df->dentry);
91}
92
f36108c4 93void hypfs_dbfs_init(void)
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94{
95 dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
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96}
97
98void hypfs_dbfs_exit(void)
99{
100 debugfs_remove(dbfs_dir);
101}