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internal.h
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1 /* Internal definitions for FS-Cache
2  *
3  * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells ([email protected])
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 /*
13  * Lock order, in the order in which multiple locks should be obtained:
14  * - fscache_addremove_sem
15  * - cookie->lock
16  * - cookie->parent->lock
17  * - cache->object_list_lock
18  * - object->lock
19  * - object->parent->lock
20  * - cookie->stores_lock
21  * - fscache_thread_lock
22  *
23  */
24 
25 #include <linux/fscache-cache.h>
26 #include <linux/sched.h>
27 
28 #define FSCACHE_MIN_THREADS 4
29 #define FSCACHE_MAX_THREADS 32
30 
31 /*
32  * cache.c
33  */
34 extern struct list_head fscache_cache_list;
36 
38  struct fscache_cookie *);
39 
40 /*
41  * cookie.c
42  */
43 extern struct kmem_cache *fscache_cookie_jar;
44 
45 extern void fscache_cookie_init_once(void *);
46 extern void __fscache_cookie_put(struct fscache_cookie *);
47 
48 /*
49  * fsdef.c
50  */
53 
54 /*
55  * histogram.c
56  */
57 #ifdef CONFIG_FSCACHE_HISTOGRAM
63 
64 static inline void fscache_hist(atomic_t histogram[], unsigned long start_jif)
65 {
66  unsigned long jif = jiffies - start_jif;
67  if (jif >= HZ)
68  jif = HZ - 1;
69  atomic_inc(&histogram[jif]);
70 }
71 
72 extern const struct file_operations fscache_histogram_fops;
73 
74 #else
75 #define fscache_hist(hist, start_jif) do {} while (0)
76 #endif
77 
78 /*
79  * main.c
80  */
81 extern unsigned fscache_defer_lookup;
82 extern unsigned fscache_defer_create;
83 extern unsigned fscache_debug;
84 extern struct kobject *fscache_root;
85 extern struct workqueue_struct *fscache_object_wq;
86 extern struct workqueue_struct *fscache_op_wq;
87 DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
88 
89 static inline bool fscache_object_congested(void)
90 {
91  return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
92 }
93 
94 extern int fscache_wait_bit(void *);
95 extern int fscache_wait_bit_interruptible(void *);
96 
97 /*
98  * object.c
99  */
100 extern const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5];
101 
102 extern void fscache_withdrawing_object(struct fscache_cache *,
103  struct fscache_object *);
104 extern void fscache_enqueue_object(struct fscache_object *);
105 
106 /*
107  * object-list.c
108  */
109 #ifdef CONFIG_FSCACHE_OBJECT_LIST
110 extern const struct file_operations fscache_objlist_fops;
111 
112 extern void fscache_objlist_add(struct fscache_object *);
113 #else
114 #define fscache_objlist_add(object) do {} while(0)
115 #endif
116 
117 /*
118  * operation.c
119  */
120 extern int fscache_submit_exclusive_op(struct fscache_object *,
121  struct fscache_operation *);
122 extern int fscache_submit_op(struct fscache_object *,
123  struct fscache_operation *);
124 extern int fscache_cancel_op(struct fscache_operation *);
125 extern void fscache_abort_object(struct fscache_object *);
126 extern void fscache_start_operations(struct fscache_object *);
127 extern void fscache_operation_gc(struct work_struct *);
128 
129 /*
130  * proc.c
131  */
132 #ifdef CONFIG_PROC_FS
133 extern int __init fscache_proc_init(void);
134 extern void fscache_proc_cleanup(void);
135 #else
136 #define fscache_proc_init() (0)
137 #define fscache_proc_cleanup() do {} while (0)
138 #endif
139 
140 /*
141  * stats.c
142  */
143 #ifdef CONFIG_FSCACHE_STATS
144 extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
145 extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];
146 
155 
161 
170 
181 
192 
197 
200 
207 
211 
216 
220 
230 
235 
252 
253 static inline void fscache_stat(atomic_t *stat)
254 {
255  atomic_inc(stat);
256 }
257 
258 static inline void fscache_stat_d(atomic_t *stat)
259 {
260  atomic_dec(stat);
261 }
262 
263 #define __fscache_stat(stat) (stat)
264 
265 extern const struct file_operations fscache_stats_fops;
266 #else
267 
268 #define __fscache_stat(stat) (NULL)
269 #define fscache_stat(stat) do {} while (0)
270 #define fscache_stat_d(stat) do {} while (0)
271 #endif
272 
273 /*
274  * raise an event on an object
275  * - if the event is not masked for that object, then the object is
276  * queued for attention by the thread pool.
277  */
278 static inline void fscache_raise_event(struct fscache_object *object,
279  unsigned event)
280 {
281  if (!test_and_set_bit(event, &object->events) &&
282  test_bit(event, &object->event_mask))
283  fscache_enqueue_object(object);
284 }
285 
286 /*
287  * drop a reference to a cookie
288  */
289 static inline void fscache_cookie_put(struct fscache_cookie *cookie)
290 {
291  BUG_ON(atomic_read(&cookie->usage) <= 0);
292  if (atomic_dec_and_test(&cookie->usage))
293  __fscache_cookie_put(cookie);
294 }
295 
296 /*
297  * get an extra reference to a netfs retrieval context
298  */
299 static inline
300 void *fscache_get_context(struct fscache_cookie *cookie, void *context)
301 {
302  if (cookie->def->get_context)
303  cookie->def->get_context(cookie->netfs_data, context);
304  return context;
305 }
306 
307 /*
308  * release a reference to a netfs retrieval context
309  */
310 static inline
311 void fscache_put_context(struct fscache_cookie *cookie, void *context)
312 {
313  if (cookie->def->put_context)
314  cookie->def->put_context(cookie->netfs_data, context);
315 }
316 
317 /*****************************************************************************/
318 /*
319  * debug tracing
320  */
321 #define dbgprintk(FMT, ...) \
322  printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
323 
324 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
325 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
326 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
327 
328 #define kjournal(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
329 
330 #ifdef __KDEBUG
331 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
332 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
333 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
334 
335 #elif defined(CONFIG_FSCACHE_DEBUG)
336 #define _enter(FMT, ...) \
337 do { \
338  if (__do_kdebug(ENTER)) \
339  kenter(FMT, ##__VA_ARGS__); \
340 } while (0)
341 
342 #define _leave(FMT, ...) \
343 do { \
344  if (__do_kdebug(LEAVE)) \
345  kleave(FMT, ##__VA_ARGS__); \
346 } while (0)
347 
348 #define _debug(FMT, ...) \
349 do { \
350  if (__do_kdebug(DEBUG)) \
351  kdebug(FMT, ##__VA_ARGS__); \
352 } while (0)
353 
354 #else
355 #define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
356 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
357 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
358 #endif
359 
360 /*
361  * determine whether a particular optional debugging point should be logged
362  * - we need to go through three steps to persuade cpp to correctly join the
363  * shorthand in FSCACHE_DEBUG_LEVEL with its prefix
364  */
365 #define ____do_kdebug(LEVEL, POINT) \
366  unlikely((fscache_debug & \
367  (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
368 #define ___do_kdebug(LEVEL, POINT) \
369  ____do_kdebug(LEVEL, POINT)
370 #define __do_kdebug(POINT) \
371  ___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)
372 
373 #define FSCACHE_DEBUG_CACHE 0
374 #define FSCACHE_DEBUG_COOKIE 1
375 #define FSCACHE_DEBUG_PAGE 2
376 #define FSCACHE_DEBUG_OPERATION 3
377 
378 #define FSCACHE_POINT_ENTER 1
379 #define FSCACHE_POINT_LEAVE 2
380 #define FSCACHE_POINT_DEBUG 4
381 
382 #ifndef FSCACHE_DEBUG_LEVEL
383 #define FSCACHE_DEBUG_LEVEL CACHE
384 #endif
385 
386 /*
387  * assertions
388  */
389 #if 1 /* defined(__KDEBUGALL) */
390 
391 #define ASSERT(X) \
392 do { \
393  if (unlikely(!(X))) { \
394  printk(KERN_ERR "\n"); \
395  printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
396  BUG(); \
397  } \
398 } while (0)
399 
400 #define ASSERTCMP(X, OP, Y) \
401 do { \
402  if (unlikely(!((X) OP (Y)))) { \
403  printk(KERN_ERR "\n"); \
404  printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
405  printk(KERN_ERR "%lx " #OP " %lx is false\n", \
406  (unsigned long)(X), (unsigned long)(Y)); \
407  BUG(); \
408  } \
409 } while (0)
410 
411 #define ASSERTIF(C, X) \
412 do { \
413  if (unlikely((C) && !(X))) { \
414  printk(KERN_ERR "\n"); \
415  printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
416  BUG(); \
417  } \
418 } while (0)
419 
420 #define ASSERTIFCMP(C, X, OP, Y) \
421 do { \
422  if (unlikely((C) && !((X) OP (Y)))) { \
423  printk(KERN_ERR "\n"); \
424  printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
425  printk(KERN_ERR "%lx " #OP " %lx is false\n", \
426  (unsigned long)(X), (unsigned long)(Y)); \
427  BUG(); \
428  } \
429 } while (0)
430 
431 #else
432 
433 #define ASSERT(X) do {} while (0)
434 #define ASSERTCMP(X, OP, Y) do {} while (0)
435 #define ASSERTIF(C, X) do {} while (0)
436 #define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
437 
438 #endif /* assert or not */