convert get_sb_single() users
[linux-3.10.git] / drivers / oprofile / oprofilefs.c
1 /**
2  * @file oprofilefs.c
3  *
4  * @remark Copyright 2002 OProfile authors
5  * @remark Read the file COPYING
6  *
7  * @author John Levon
8  *
9  * A simple filesystem for configuration and
10  * access of oprofile.
11  */
12
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/oprofile.h>
16 #include <linux/fs.h>
17 #include <linux/pagemap.h>
18 #include <asm/uaccess.h>
19
20 #include "oprof.h"
21
22 #define OPROFILEFS_MAGIC 0x6f70726f
23
24 DEFINE_SPINLOCK(oprofilefs_lock);
25
26 static struct inode *oprofilefs_get_inode(struct super_block *sb, int mode)
27 {
28         struct inode *inode = new_inode(sb);
29
30         if (inode) {
31                 inode->i_ino = get_next_ino();
32                 inode->i_mode = mode;
33                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
34         }
35         return inode;
36 }
37
38
39 static const struct super_operations s_ops = {
40         .statfs         = simple_statfs,
41         .drop_inode     = generic_delete_inode,
42 };
43
44
45 ssize_t oprofilefs_str_to_user(char const *str, char __user *buf, size_t count, loff_t *offset)
46 {
47         return simple_read_from_buffer(buf, count, offset, str, strlen(str));
48 }
49
50
51 #define TMPBUFSIZE 50
52
53 ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset)
54 {
55         char tmpbuf[TMPBUFSIZE];
56         size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
57         if (maxlen > TMPBUFSIZE)
58                 maxlen = TMPBUFSIZE;
59         return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
60 }
61
62
63 int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count)
64 {
65         char tmpbuf[TMPBUFSIZE];
66         unsigned long flags;
67
68         if (!count)
69                 return 0;
70
71         if (count > TMPBUFSIZE - 1)
72                 return -EINVAL;
73
74         memset(tmpbuf, 0x0, TMPBUFSIZE);
75
76         if (copy_from_user(tmpbuf, buf, count))
77                 return -EFAULT;
78
79         spin_lock_irqsave(&oprofilefs_lock, flags);
80         *val = simple_strtoul(tmpbuf, NULL, 0);
81         spin_unlock_irqrestore(&oprofilefs_lock, flags);
82         return 0;
83 }
84
85
86 static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
87 {
88         unsigned long *val = file->private_data;
89         return oprofilefs_ulong_to_user(*val, buf, count, offset);
90 }
91
92
93 static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
94 {
95         unsigned long value;
96         int retval;
97
98         if (*offset)
99                 return -EINVAL;
100
101         retval = oprofilefs_ulong_from_user(&value, buf, count);
102         if (retval)
103                 return retval;
104
105         retval = oprofile_set_ulong(file->private_data, value);
106         if (retval)
107                 return retval;
108
109         return count;
110 }
111
112
113 static int default_open(struct inode *inode, struct file *filp)
114 {
115         if (inode->i_private)
116                 filp->private_data = inode->i_private;
117         return 0;
118 }
119
120
121 static const struct file_operations ulong_fops = {
122         .read           = ulong_read_file,
123         .write          = ulong_write_file,
124         .open           = default_open,
125         .llseek         = default_llseek,
126 };
127
128
129 static const struct file_operations ulong_ro_fops = {
130         .read           = ulong_read_file,
131         .open           = default_open,
132         .llseek         = default_llseek,
133 };
134
135
136 static int __oprofilefs_create_file(struct super_block *sb,
137         struct dentry *root, char const *name, const struct file_operations *fops,
138         int perm, void *priv)
139 {
140         struct dentry *dentry;
141         struct inode *inode;
142
143         dentry = d_alloc_name(root, name);
144         if (!dentry)
145                 return -ENOMEM;
146         inode = oprofilefs_get_inode(sb, S_IFREG | perm);
147         if (!inode) {
148                 dput(dentry);
149                 return -ENOMEM;
150         }
151         inode->i_fop = fops;
152         d_add(dentry, inode);
153         dentry->d_inode->i_private = priv;
154         return 0;
155 }
156
157
158 int oprofilefs_create_ulong(struct super_block *sb, struct dentry *root,
159         char const *name, unsigned long *val)
160 {
161         return __oprofilefs_create_file(sb, root, name,
162                                         &ulong_fops, 0644, val);
163 }
164
165
166 int oprofilefs_create_ro_ulong(struct super_block *sb, struct dentry *root,
167         char const *name, unsigned long *val)
168 {
169         return __oprofilefs_create_file(sb, root, name,
170                                         &ulong_ro_fops, 0444, val);
171 }
172
173
174 static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
175 {
176         atomic_t *val = file->private_data;
177         return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset);
178 }
179
180
181 static const struct file_operations atomic_ro_fops = {
182         .read           = atomic_read_file,
183         .open           = default_open,
184         .llseek         = default_llseek,
185 };
186
187
188 int oprofilefs_create_ro_atomic(struct super_block *sb, struct dentry *root,
189         char const *name, atomic_t *val)
190 {
191         return __oprofilefs_create_file(sb, root, name,
192                                         &atomic_ro_fops, 0444, val);
193 }
194
195
196 int oprofilefs_create_file(struct super_block *sb, struct dentry *root,
197         char const *name, const struct file_operations *fops)
198 {
199         return __oprofilefs_create_file(sb, root, name, fops, 0644, NULL);
200 }
201
202
203 int oprofilefs_create_file_perm(struct super_block *sb, struct dentry *root,
204         char const *name, const struct file_operations *fops, int perm)
205 {
206         return __oprofilefs_create_file(sb, root, name, fops, perm, NULL);
207 }
208
209
210 struct dentry *oprofilefs_mkdir(struct super_block *sb,
211         struct dentry *root, char const *name)
212 {
213         struct dentry *dentry;
214         struct inode *inode;
215
216         dentry = d_alloc_name(root, name);
217         if (!dentry)
218                 return NULL;
219         inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
220         if (!inode) {
221                 dput(dentry);
222                 return NULL;
223         }
224         inode->i_op = &simple_dir_inode_operations;
225         inode->i_fop = &simple_dir_operations;
226         d_add(dentry, inode);
227         return dentry;
228 }
229
230
231 static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent)
232 {
233         struct inode *root_inode;
234         struct dentry *root_dentry;
235
236         sb->s_blocksize = PAGE_CACHE_SIZE;
237         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
238         sb->s_magic = OPROFILEFS_MAGIC;
239         sb->s_op = &s_ops;
240         sb->s_time_gran = 1;
241
242         root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
243         if (!root_inode)
244                 return -ENOMEM;
245         root_inode->i_op = &simple_dir_inode_operations;
246         root_inode->i_fop = &simple_dir_operations;
247         root_dentry = d_alloc_root(root_inode);
248         if (!root_dentry) {
249                 iput(root_inode);
250                 return -ENOMEM;
251         }
252
253         sb->s_root = root_dentry;
254
255         oprofile_create_files(sb, root_dentry);
256
257         // FIXME: verify kill_litter_super removes our dentries
258         return 0;
259 }
260
261
262 static struct dentry *oprofilefs_mount(struct file_system_type *fs_type,
263         int flags, const char *dev_name, void *data)
264 {
265         return mount_single(fs_type, flags, data, oprofilefs_fill_super);
266 }
267
268
269 static struct file_system_type oprofilefs_type = {
270         .owner          = THIS_MODULE,
271         .name           = "oprofilefs",
272         .mount          = oprofilefs_mount,
273         .kill_sb        = kill_litter_super,
274 };
275
276
277 int __init oprofilefs_register(void)
278 {
279         return register_filesystem(&oprofilefs_type);
280 }
281
282
283 void __exit oprofilefs_unregister(void)
284 {
285         unregister_filesystem(&oprofilefs_type);
286 }