USB: musb: do not work if no gadget driver is loaded
[linux-2.6.git] / fs / fscache / object-list.c
1 /* Global fscache object list maintainer and viewer
2  *
3  * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public Licence
8  * as published by the Free Software Foundation; either version
9  * 2 of the Licence, or (at your option) any later version.
10  */
11
12 #define FSCACHE_DEBUG_LEVEL COOKIE
13 #include <linux/module.h>
14 #include <linux/seq_file.h>
15 #include <linux/key.h>
16 #include <keys/user-type.h>
17 #include "internal.h"
18
19 static struct rb_root fscache_object_list;
20 static DEFINE_RWLOCK(fscache_object_list_lock);
21
22 struct fscache_objlist_data {
23         unsigned long   config;         /* display configuration */
24 #define FSCACHE_OBJLIST_CONFIG_KEY      0x00000001      /* show object keys */
25 #define FSCACHE_OBJLIST_CONFIG_AUX      0x00000002      /* show object auxdata */
26 #define FSCACHE_OBJLIST_CONFIG_COOKIE   0x00000004      /* show objects with cookies */
27 #define FSCACHE_OBJLIST_CONFIG_NOCOOKIE 0x00000008      /* show objects without cookies */
28 #define FSCACHE_OBJLIST_CONFIG_BUSY     0x00000010      /* show busy objects */
29 #define FSCACHE_OBJLIST_CONFIG_IDLE     0x00000020      /* show idle objects */
30 #define FSCACHE_OBJLIST_CONFIG_PENDWR   0x00000040      /* show objects with pending writes */
31 #define FSCACHE_OBJLIST_CONFIG_NOPENDWR 0x00000080      /* show objects without pending writes */
32 #define FSCACHE_OBJLIST_CONFIG_READS    0x00000100      /* show objects with active reads */
33 #define FSCACHE_OBJLIST_CONFIG_NOREADS  0x00000200      /* show objects without active reads */
34 #define FSCACHE_OBJLIST_CONFIG_EVENTS   0x00000400      /* show objects with events */
35 #define FSCACHE_OBJLIST_CONFIG_NOEVENTS 0x00000800      /* show objects without no events */
36 #define FSCACHE_OBJLIST_CONFIG_WORK     0x00001000      /* show objects with slow work */
37 #define FSCACHE_OBJLIST_CONFIG_NOWORK   0x00002000      /* show objects without slow work */
38
39         u8              buf[512];       /* key and aux data buffer */
40 };
41
42 /*
43  * Add an object to the object list
44  * - we use the address of the fscache_object structure as the key into the
45  *   tree
46  */
47 void fscache_objlist_add(struct fscache_object *obj)
48 {
49         struct fscache_object *xobj;
50         struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
51
52         write_lock(&fscache_object_list_lock);
53
54         while (*p) {
55                 parent = *p;
56                 xobj = rb_entry(parent, struct fscache_object, objlist_link);
57
58                 if (obj < xobj)
59                         p = &(*p)->rb_left;
60                 else if (obj > xobj)
61                         p = &(*p)->rb_right;
62                 else
63                         BUG();
64         }
65
66         rb_link_node(&obj->objlist_link, parent, p);
67         rb_insert_color(&obj->objlist_link, &fscache_object_list);
68
69         write_unlock(&fscache_object_list_lock);
70 }
71
72 /**
73  * fscache_object_destroy - Note that a cache object is about to be destroyed
74  * @object: The object to be destroyed
75  *
76  * Note the imminent destruction and deallocation of a cache object record.
77  */
78 void fscache_object_destroy(struct fscache_object *obj)
79 {
80         write_lock(&fscache_object_list_lock);
81
82         BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
83         rb_erase(&obj->objlist_link, &fscache_object_list);
84
85         write_unlock(&fscache_object_list_lock);
86 }
87 EXPORT_SYMBOL(fscache_object_destroy);
88
89 /*
90  * find the object in the tree on or after the specified index
91  */
92 static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
93 {
94         struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
95         struct rb_node *p;
96         unsigned long pos;
97
98         if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
99                 return NULL;
100         pos = *_pos;
101
102         /* banners (can't represent line 0 by pos 0 as that would involve
103          * returning a NULL pointer) */
104         if (pos == 0)
105                 return (struct fscache_object *) ++(*_pos);
106         if (pos < 3)
107                 return (struct fscache_object *)pos;
108
109         pobj = (struct fscache_object *)pos;
110         p = fscache_object_list.rb_node;
111         while (p) {
112                 obj = rb_entry(p, struct fscache_object, objlist_link);
113                 if (pobj < obj) {
114                         if (!minobj || minobj > obj)
115                                 minobj = obj;
116                         p = p->rb_left;
117                 } else if (pobj > obj) {
118                         p = p->rb_right;
119                 } else {
120                         minobj = obj;
121                         break;
122                 }
123                 obj = NULL;
124         }
125
126         if (!minobj)
127                 *_pos = (unsigned long) ERR_PTR(-ENOENT);
128         else if (minobj != obj)
129                 *_pos = (unsigned long) minobj;
130         return minobj;
131 }
132
133 /*
134  * set up the iterator to start reading from the first line
135  */
136 static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
137         __acquires(&fscache_object_list_lock)
138 {
139         read_lock(&fscache_object_list_lock);
140         return fscache_objlist_lookup(_pos);
141 }
142
143 /*
144  * move to the next line
145  */
146 static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
147 {
148         (*_pos)++;
149         return fscache_objlist_lookup(_pos);
150 }
151
152 /*
153  * clean up after reading
154  */
155 static void fscache_objlist_stop(struct seq_file *m, void *v)
156         __releases(&fscache_object_list_lock)
157 {
158         read_unlock(&fscache_object_list_lock);
159 }
160
161 /*
162  * display an object
163  */
164 static int fscache_objlist_show(struct seq_file *m, void *v)
165 {
166         struct fscache_objlist_data *data = m->private;
167         struct fscache_object *obj = v;
168         unsigned long config = data->config;
169         uint16_t keylen, auxlen;
170         char _type[3], *type;
171         bool no_cookie;
172         u8 *buf = data->buf, *p;
173
174         if ((unsigned long) v == 1) {
175                 seq_puts(m, "OBJECT   PARENT   STAT CHLDN OPS OOP IPR EX READS"
176                          " EM EV F S"
177                          " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
178                 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
179                               FSCACHE_OBJLIST_CONFIG_AUX))
180                         seq_puts(m, "       ");
181                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
182                         seq_puts(m, "OBJECT_KEY");
183                 if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
184                                FSCACHE_OBJLIST_CONFIG_AUX)) ==
185                     (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
186                         seq_puts(m, ", ");
187                 if (config & FSCACHE_OBJLIST_CONFIG_AUX)
188                         seq_puts(m, "AUX_DATA");
189                 seq_puts(m, "\n");
190                 return 0;
191         }
192
193         if ((unsigned long) v == 2) {
194                 seq_puts(m, "======== ======== ==== ===== === === === == ====="
195                          " == == = ="
196                          " | ================ == == ================");
197                 if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
198                               FSCACHE_OBJLIST_CONFIG_AUX))
199                         seq_puts(m, " ================");
200                 seq_puts(m, "\n");
201                 return 0;
202         }
203
204         /* filter out any unwanted objects */
205 #define FILTER(criterion, _yes, _no)                                    \
206         do {                                                            \
207                 unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes;      \
208                 unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no;        \
209                 if (criterion) {                                        \
210                         if (!(config & yes))                            \
211                                 return 0;                               \
212                 } else {                                                \
213                         if (!(config & no))                             \
214                                 return 0;                               \
215                 }                                                       \
216         } while(0)
217
218         if (~config) {
219                 FILTER(obj->cookie,
220                        COOKIE, NOCOOKIE);
221                 FILTER(obj->state != FSCACHE_OBJECT_ACTIVE ||
222                        obj->n_ops != 0 ||
223                        obj->n_obj_ops != 0 ||
224                        obj->flags ||
225                        !list_empty(&obj->dependents),
226                        BUSY, IDLE);
227                 FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
228                        PENDWR, NOPENDWR);
229                 FILTER(atomic_read(&obj->n_reads),
230                        READS, NOREADS);
231                 FILTER(obj->events & obj->event_mask,
232                        EVENTS, NOEVENTS);
233                 FILTER(obj->work.flags & ~(1UL << SLOW_WORK_VERY_SLOW),
234                        WORK, NOWORK);
235         }
236
237         seq_printf(m,
238                    "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1lx | ",
239                    obj->debug_id,
240                    obj->parent ? obj->parent->debug_id : -1,
241                    fscache_object_states_short[obj->state],
242                    obj->n_children,
243                    obj->n_ops,
244                    obj->n_obj_ops,
245                    obj->n_in_progress,
246                    obj->n_exclusive,
247                    atomic_read(&obj->n_reads),
248                    obj->event_mask & FSCACHE_OBJECT_EVENTS_MASK,
249                    obj->events,
250                    obj->flags,
251                    obj->work.flags);
252
253         no_cookie = true;
254         keylen = auxlen = 0;
255         if (obj->cookie) {
256                 spin_lock(&obj->lock);
257                 if (obj->cookie) {
258                         switch (obj->cookie->def->type) {
259                         case 0:
260                                 type = "IX";
261                                 break;
262                         case 1:
263                                 type = "DT";
264                                 break;
265                         default:
266                                 sprintf(_type, "%02u",
267                                         obj->cookie->def->type);
268                                 type = _type;
269                                 break;
270                         }
271
272                         seq_printf(m, "%-16s %s %2lx %16p",
273                                    obj->cookie->def->name,
274                                    type,
275                                    obj->cookie->flags,
276                                    obj->cookie->netfs_data);
277
278                         if (obj->cookie->def->get_key &&
279                             config & FSCACHE_OBJLIST_CONFIG_KEY)
280                                 keylen = obj->cookie->def->get_key(
281                                         obj->cookie->netfs_data,
282                                         buf, 400);
283
284                         if (obj->cookie->def->get_aux &&
285                             config & FSCACHE_OBJLIST_CONFIG_AUX)
286                                 auxlen = obj->cookie->def->get_aux(
287                                         obj->cookie->netfs_data,
288                                         buf + keylen, 512 - keylen);
289
290                         no_cookie = false;
291                 }
292                 spin_unlock(&obj->lock);
293
294                 if (!no_cookie && (keylen > 0 || auxlen > 0)) {
295                         seq_printf(m, " ");
296                         for (p = buf; keylen > 0; keylen--)
297                                 seq_printf(m, "%02x", *p++);
298                         if (auxlen > 0) {
299                                 if (config & FSCACHE_OBJLIST_CONFIG_KEY)
300                                         seq_printf(m, ", ");
301                                 for (; auxlen > 0; auxlen--)
302                                         seq_printf(m, "%02x", *p++);
303                         }
304                 }
305         }
306
307         if (no_cookie)
308                 seq_printf(m, "<no_cookie>\n");
309         else
310                 seq_printf(m, "\n");
311         return 0;
312 }
313
314 static const struct seq_operations fscache_objlist_ops = {
315         .start          = fscache_objlist_start,
316         .stop           = fscache_objlist_stop,
317         .next           = fscache_objlist_next,
318         .show           = fscache_objlist_show,
319 };
320
321 /*
322  * get the configuration for filtering the list
323  */
324 static void fscache_objlist_config(struct fscache_objlist_data *data)
325 {
326 #ifdef CONFIG_KEYS
327         struct user_key_payload *confkey;
328         unsigned long config;
329         struct key *key;
330         const char *buf;
331         int len;
332
333         key = request_key(&key_type_user, "fscache:objlist", NULL);
334         if (IS_ERR(key))
335                 goto no_config;
336
337         config = 0;
338         rcu_read_lock();
339
340         confkey = key->payload.data;
341         buf = confkey->data;
342
343         for (len = confkey->datalen - 1; len >= 0; len--) {
344                 switch (buf[len]) {
345                 case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;         break;
346                 case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;         break;
347                 case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;      break;
348                 case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;    break;
349                 case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;        break;
350                 case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;        break;
351                 case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;      break;
352                 case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;    break;
353                 case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;       break;
354                 case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;     break;
355                 case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;        break;
356                 case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;      break;
357                 }
358         }
359
360         rcu_read_unlock();
361         key_put(key);
362
363         if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
364             config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
365         if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
366             config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
367         if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
368             config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
369         if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
370             config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
371         if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
372             config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
373         if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
374             config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
375
376         data->config = config;
377         return;
378
379 no_config:
380 #endif
381         data->config = ULONG_MAX;
382 }
383
384 /*
385  * open "/proc/fs/fscache/objects" to provide a list of active objects
386  * - can be configured by a user-defined key added to the caller's keyrings
387  */
388 static int fscache_objlist_open(struct inode *inode, struct file *file)
389 {
390         struct fscache_objlist_data *data;
391         struct seq_file *m;
392         int ret;
393
394         ret = seq_open(file, &fscache_objlist_ops);
395         if (ret < 0)
396                 return ret;
397
398         m = file->private_data;
399
400         /* buffer for key extraction */
401         data = kmalloc(sizeof(struct fscache_objlist_data), GFP_KERNEL);
402         if (!data) {
403                 seq_release(inode, file);
404                 return -ENOMEM;
405         }
406
407         /* get the configuration key */
408         fscache_objlist_config(data);
409
410         m->private = data;
411         return 0;
412 }
413
414 /*
415  * clean up on close
416  */
417 static int fscache_objlist_release(struct inode *inode, struct file *file)
418 {
419         struct seq_file *m = file->private_data;
420
421         kfree(m->private);
422         m->private = NULL;
423         return seq_release(inode, file);
424 }
425
426 const struct file_operations fscache_objlist_fops = {
427         .owner          = THIS_MODULE,
428         .open           = fscache_objlist_open,
429         .read           = seq_read,
430         .llseek         = seq_lseek,
431         .release        = fscache_objlist_release,
432 };