fs: dcache rationalise dget variants
[linux-2.6.git] / drivers / infiniband / hw / ipath / ipath_fs.c
1 /*
2  * Copyright (c) 2006, 2007 QLogic Corporation. All rights reserved.
3  * Copyright (c) 2006 PathScale, Inc. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33
34 #include <linux/module.h>
35 #include <linux/fs.h>
36 #include <linux/mount.h>
37 #include <linux/pagemap.h>
38 #include <linux/init.h>
39 #include <linux/namei.h>
40 #include <linux/slab.h>
41
42 #include "ipath_kernel.h"
43
44 #define IPATHFS_MAGIC 0x726a77
45
46 static struct super_block *ipath_super;
47
48 static int ipathfs_mknod(struct inode *dir, struct dentry *dentry,
49                          int mode, const struct file_operations *fops,
50                          void *data)
51 {
52         int error;
53         struct inode *inode = new_inode(dir->i_sb);
54
55         if (!inode) {
56                 error = -EPERM;
57                 goto bail;
58         }
59
60         inode->i_ino = get_next_ino();
61         inode->i_mode = mode;
62         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
63         inode->i_private = data;
64         if ((mode & S_IFMT) == S_IFDIR) {
65                 inode->i_op = &simple_dir_inode_operations;
66                 inc_nlink(inode);
67                 inc_nlink(dir);
68         }
69
70         inode->i_fop = fops;
71
72         d_instantiate(dentry, inode);
73         error = 0;
74
75 bail:
76         return error;
77 }
78
79 static int create_file(const char *name, mode_t mode,
80                        struct dentry *parent, struct dentry **dentry,
81                        const struct file_operations *fops, void *data)
82 {
83         int error;
84
85         *dentry = NULL;
86         mutex_lock(&parent->d_inode->i_mutex);
87         *dentry = lookup_one_len(name, parent, strlen(name));
88         if (!IS_ERR(*dentry))
89                 error = ipathfs_mknod(parent->d_inode, *dentry,
90                                       mode, fops, data);
91         else
92                 error = PTR_ERR(dentry);
93         mutex_unlock(&parent->d_inode->i_mutex);
94
95         return error;
96 }
97
98 static ssize_t atomic_stats_read(struct file *file, char __user *buf,
99                                  size_t count, loff_t *ppos)
100 {
101         return simple_read_from_buffer(buf, count, ppos, &ipath_stats,
102                                        sizeof ipath_stats);
103 }
104
105 static const struct file_operations atomic_stats_ops = {
106         .read = atomic_stats_read,
107         .llseek = default_llseek,
108 };
109
110 static ssize_t atomic_counters_read(struct file *file, char __user *buf,
111                                     size_t count, loff_t *ppos)
112 {
113         struct infinipath_counters counters;
114         struct ipath_devdata *dd;
115
116         dd = file->f_path.dentry->d_inode->i_private;
117         dd->ipath_f_read_counters(dd, &counters);
118
119         return simple_read_from_buffer(buf, count, ppos, &counters,
120                                        sizeof counters);
121 }
122
123 static const struct file_operations atomic_counters_ops = {
124         .read = atomic_counters_read,
125         .llseek = default_llseek,
126 };
127
128 static ssize_t flash_read(struct file *file, char __user *buf,
129                           size_t count, loff_t *ppos)
130 {
131         struct ipath_devdata *dd;
132         ssize_t ret;
133         loff_t pos;
134         char *tmp;
135
136         pos = *ppos;
137
138         if ( pos < 0) {
139                 ret = -EINVAL;
140                 goto bail;
141         }
142
143         if (pos >= sizeof(struct ipath_flash)) {
144                 ret = 0;
145                 goto bail;
146         }
147
148         if (count > sizeof(struct ipath_flash) - pos)
149                 count = sizeof(struct ipath_flash) - pos;
150
151         tmp = kmalloc(count, GFP_KERNEL);
152         if (!tmp) {
153                 ret = -ENOMEM;
154                 goto bail;
155         }
156
157         dd = file->f_path.dentry->d_inode->i_private;
158         if (ipath_eeprom_read(dd, pos, tmp, count)) {
159                 ipath_dev_err(dd, "failed to read from flash\n");
160                 ret = -ENXIO;
161                 goto bail_tmp;
162         }
163
164         if (copy_to_user(buf, tmp, count)) {
165                 ret = -EFAULT;
166                 goto bail_tmp;
167         }
168
169         *ppos = pos + count;
170         ret = count;
171
172 bail_tmp:
173         kfree(tmp);
174
175 bail:
176         return ret;
177 }
178
179 static ssize_t flash_write(struct file *file, const char __user *buf,
180                            size_t count, loff_t *ppos)
181 {
182         struct ipath_devdata *dd;
183         ssize_t ret;
184         loff_t pos;
185         char *tmp;
186
187         pos = *ppos;
188
189         if (pos != 0) {
190                 ret = -EINVAL;
191                 goto bail;
192         }
193
194         if (count != sizeof(struct ipath_flash)) {
195                 ret = -EINVAL;
196                 goto bail;
197         }
198
199         tmp = kmalloc(count, GFP_KERNEL);
200         if (!tmp) {
201                 ret = -ENOMEM;
202                 goto bail;
203         }
204
205         if (copy_from_user(tmp, buf, count)) {
206                 ret = -EFAULT;
207                 goto bail_tmp;
208         }
209
210         dd = file->f_path.dentry->d_inode->i_private;
211         if (ipath_eeprom_write(dd, pos, tmp, count)) {
212                 ret = -ENXIO;
213                 ipath_dev_err(dd, "failed to write to flash\n");
214                 goto bail_tmp;
215         }
216
217         *ppos = pos + count;
218         ret = count;
219
220 bail_tmp:
221         kfree(tmp);
222
223 bail:
224         return ret;
225 }
226
227 static const struct file_operations flash_ops = {
228         .read = flash_read,
229         .write = flash_write,
230         .llseek = default_llseek,
231 };
232
233 static int create_device_files(struct super_block *sb,
234                                struct ipath_devdata *dd)
235 {
236         struct dentry *dir, *tmp;
237         char unit[10];
238         int ret;
239
240         snprintf(unit, sizeof unit, "%02d", dd->ipath_unit);
241         ret = create_file(unit, S_IFDIR|S_IRUGO|S_IXUGO, sb->s_root, &dir,
242                           &simple_dir_operations, dd);
243         if (ret) {
244                 printk(KERN_ERR "create_file(%s) failed: %d\n", unit, ret);
245                 goto bail;
246         }
247
248         ret = create_file("atomic_counters", S_IFREG|S_IRUGO, dir, &tmp,
249                           &atomic_counters_ops, dd);
250         if (ret) {
251                 printk(KERN_ERR "create_file(%s/atomic_counters) "
252                        "failed: %d\n", unit, ret);
253                 goto bail;
254         }
255
256         ret = create_file("flash", S_IFREG|S_IWUSR|S_IRUGO, dir, &tmp,
257                           &flash_ops, dd);
258         if (ret) {
259                 printk(KERN_ERR "create_file(%s/flash) "
260                        "failed: %d\n", unit, ret);
261                 goto bail;
262         }
263
264 bail:
265         return ret;
266 }
267
268 static int remove_file(struct dentry *parent, char *name)
269 {
270         struct dentry *tmp;
271         int ret;
272
273         tmp = lookup_one_len(name, parent, strlen(name));
274
275         if (IS_ERR(tmp)) {
276                 ret = PTR_ERR(tmp);
277                 goto bail;
278         }
279
280         spin_lock(&tmp->d_lock);
281         if (!(d_unhashed(tmp) && tmp->d_inode)) {
282                 dget_dlock(tmp);
283                 __d_drop(tmp);
284                 spin_unlock(&tmp->d_lock);
285                 simple_unlink(parent->d_inode, tmp);
286         } else
287                 spin_unlock(&tmp->d_lock);
288
289         ret = 0;
290 bail:
291         /*
292          * We don't expect clients to care about the return value, but
293          * it's there if they need it.
294          */
295         return ret;
296 }
297
298 static int remove_device_files(struct super_block *sb,
299                                struct ipath_devdata *dd)
300 {
301         struct dentry *dir, *root;
302         char unit[10];
303         int ret;
304
305         root = dget(sb->s_root);
306         mutex_lock(&root->d_inode->i_mutex);
307         snprintf(unit, sizeof unit, "%02d", dd->ipath_unit);
308         dir = lookup_one_len(unit, root, strlen(unit));
309
310         if (IS_ERR(dir)) {
311                 ret = PTR_ERR(dir);
312                 printk(KERN_ERR "Lookup of %s failed\n", unit);
313                 goto bail;
314         }
315
316         remove_file(dir, "flash");
317         remove_file(dir, "atomic_counters");
318         d_delete(dir);
319         ret = simple_rmdir(root->d_inode, dir);
320
321 bail:
322         mutex_unlock(&root->d_inode->i_mutex);
323         dput(root);
324         return ret;
325 }
326
327 static int ipathfs_fill_super(struct super_block *sb, void *data,
328                               int silent)
329 {
330         struct ipath_devdata *dd, *tmp;
331         unsigned long flags;
332         int ret;
333
334         static struct tree_descr files[] = {
335                 [2] = {"atomic_stats", &atomic_stats_ops, S_IRUGO},
336                 {""},
337         };
338
339         ret = simple_fill_super(sb, IPATHFS_MAGIC, files);
340         if (ret) {
341                 printk(KERN_ERR "simple_fill_super failed: %d\n", ret);
342                 goto bail;
343         }
344
345         spin_lock_irqsave(&ipath_devs_lock, flags);
346
347         list_for_each_entry_safe(dd, tmp, &ipath_dev_list, ipath_list) {
348                 spin_unlock_irqrestore(&ipath_devs_lock, flags);
349                 ret = create_device_files(sb, dd);
350                 if (ret)
351                         goto bail;
352                 spin_lock_irqsave(&ipath_devs_lock, flags);
353         }
354
355         spin_unlock_irqrestore(&ipath_devs_lock, flags);
356
357 bail:
358         return ret;
359 }
360
361 static struct dentry *ipathfs_mount(struct file_system_type *fs_type,
362                         int flags, const char *dev_name, void *data)
363 {
364         struct dentry *ret;
365         ret = mount_single(fs_type, flags, data, ipathfs_fill_super);
366         if (!IS_ERR(ret))
367                 ipath_super = ret->d_sb;
368         return ret;
369 }
370
371 static void ipathfs_kill_super(struct super_block *s)
372 {
373         kill_litter_super(s);
374         ipath_super = NULL;
375 }
376
377 int ipathfs_add_device(struct ipath_devdata *dd)
378 {
379         int ret;
380
381         if (ipath_super == NULL) {
382                 ret = 0;
383                 goto bail;
384         }
385
386         ret = create_device_files(ipath_super, dd);
387
388 bail:
389         return ret;
390 }
391
392 int ipathfs_remove_device(struct ipath_devdata *dd)
393 {
394         int ret;
395
396         if (ipath_super == NULL) {
397                 ret = 0;
398                 goto bail;
399         }
400
401         ret = remove_device_files(ipath_super, dd);
402
403 bail:
404         return ret;
405 }
406
407 static struct file_system_type ipathfs_fs_type = {
408         .owner =        THIS_MODULE,
409         .name =         "ipathfs",
410         .mount =        ipathfs_mount,
411         .kill_sb =      ipathfs_kill_super,
412 };
413
414 int __init ipath_init_ipathfs(void)
415 {
416         return register_filesystem(&ipathfs_fs_type);
417 }
418
419 void __exit ipath_exit_ipathfs(void)
420 {
421         unregister_filesystem(&ipathfs_fs_type);
422 }