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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Hypervisor filesystem for Linux on s390 - debugfs interface
4 *
5 * Copyright IBM Corp. 2010
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;
21 data->dbfs_file = f;
22 return data;
23}
24
25static void hypfs_dbfs_data_free(struct hypfs_dbfs_data *data)
26{
27 data->dbfs_file->data_free(data->buf_free_ptr);
28 kfree(data);
29}
30
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
41 df = file_inode(file)->i_private;
42 mutex_lock(&df->lock);
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;
53 }
54 mutex_unlock(&df->lock);
55
56 rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
57 hypfs_dbfs_data_free(data);
58 return rc;
59}
60
61static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
62{
63 struct hypfs_dbfs_file *df = file_inode(file)->i_private;
64 long rc;
65
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
75static const struct file_operations dbfs_ops = {
76 .read = dbfs_read,
77 .llseek = no_llseek,
78 .unlocked_ioctl = dbfs_ioctl,
79};
80
81void hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
82{
83 df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df,
84 &dbfs_ops);
85 mutex_init(&df->lock);
86}
87
88void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
89{
90 debugfs_remove(df->dentry);
91}
92
93void hypfs_dbfs_init(void)
94{
95 dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
96}
97
98void hypfs_dbfs_exit(void)
99{
100 debugfs_remove(dbfs_dir);
101}
1/*
2 * Hypervisor filesystem for Linux on s390 - debugfs interface
3 *
4 * Copyright (C) IBM Corp. 2010
5 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
6 */
7
8#include <linux/slab.h>
9#include "hypfs.h"
10
11static struct dentry *dbfs_dir;
12
13static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f)
14{
15 struct hypfs_dbfs_data *data;
16
17 data = kmalloc(sizeof(*data), GFP_KERNEL);
18 if (!data)
19 return NULL;
20 kref_init(&data->kref);
21 data->dbfs_file = f;
22 return data;
23}
24
25static void hypfs_dbfs_data_free(struct kref *kref)
26{
27 struct hypfs_dbfs_data *data;
28
29 data = container_of(kref, struct hypfs_dbfs_data, kref);
30 data->dbfs_file->data_free(data->buf_free_ptr);
31 kfree(data);
32}
33
34static void data_free_delayed(struct work_struct *work)
35{
36 struct hypfs_dbfs_data *data;
37 struct hypfs_dbfs_file *df;
38
39 df = container_of(work, struct hypfs_dbfs_file, data_free_work.work);
40 mutex_lock(&df->lock);
41 data = df->data;
42 df->data = NULL;
43 mutex_unlock(&df->lock);
44 kref_put(&data->kref, hypfs_dbfs_data_free);
45}
46
47static ssize_t dbfs_read(struct file *file, char __user *buf,
48 size_t size, loff_t *ppos)
49{
50 struct hypfs_dbfs_data *data;
51 struct hypfs_dbfs_file *df;
52 ssize_t rc;
53
54 if (*ppos != 0)
55 return 0;
56
57 df = file->f_path.dentry->d_inode->i_private;
58 mutex_lock(&df->lock);
59 if (!df->data) {
60 data = hypfs_dbfs_data_alloc(df);
61 if (!data) {
62 mutex_unlock(&df->lock);
63 return -ENOMEM;
64 }
65 rc = df->data_create(&data->buf, &data->buf_free_ptr,
66 &data->size);
67 if (rc) {
68 mutex_unlock(&df->lock);
69 kfree(data);
70 return rc;
71 }
72 df->data = data;
73 schedule_delayed_work(&df->data_free_work, HZ);
74 }
75 data = df->data;
76 kref_get(&data->kref);
77 mutex_unlock(&df->lock);
78
79 rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size);
80 kref_put(&data->kref, hypfs_dbfs_data_free);
81 return rc;
82}
83
84static const struct file_operations dbfs_ops = {
85 .read = dbfs_read,
86 .llseek = no_llseek,
87};
88
89int hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
90{
91 df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df,
92 &dbfs_ops);
93 if (IS_ERR(df->dentry))
94 return PTR_ERR(df->dentry);
95 mutex_init(&df->lock);
96 INIT_DELAYED_WORK(&df->data_free_work, data_free_delayed);
97 return 0;
98}
99
100void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
101{
102 debugfs_remove(df->dentry);
103}
104
105int hypfs_dbfs_init(void)
106{
107 dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
108 if (IS_ERR(dbfs_dir))
109 return PTR_ERR(dbfs_dir);
110 return 0;
111}
112
113void hypfs_dbfs_exit(void)
114{
115 debugfs_remove(dbfs_dir);
116}