1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Fast and scalable bitmaps.
4  *
5  * Copyright (C) 2016 Facebook
6  * Copyright (C) 2013-2014 Jens Axboe
7  */
8 
9 #ifndef __LINUX_SCALE_BITMAP_H
10 #define __LINUX_SCALE_BITMAP_H
11 
12 #include <linux/atomic.h>
13 #include <linux/bitops.h>
14 #include <linux/cache.h>
15 #include <linux/list.h>
16 #include <linux/log2.h>
17 #include <linux/minmax.h>
18 #include <linux/percpu.h>
19 #include <linux/slab.h>
20 #include <linux/smp.h>
21 #include <linux/types.h>
22 #include <linux/wait.h>
23 
24 struct seq_file;
25 
26 /**
27  * struct sbitmap_word - Word in a &struct sbitmap.
28  */
29 struct sbitmap_word {
30 	/**
31 	 * @word: word holding free bits
32 	 */
33 	unsigned long word;
34 
35 	/**
36 	 * @cleared: word holding cleared bits
37 	 */
38 	unsigned long cleared ____cacheline_aligned_in_smp;
39 } ____cacheline_aligned_in_smp;
40 
41 /**
42  * struct sbitmap - Scalable bitmap.
43  *
44  * A &struct sbitmap is spread over multiple cachelines to avoid ping-pong. This
45  * trades off higher memory usage for better scalability.
46  */
47 struct sbitmap {
48 	/**
49 	 * @depth: Number of bits used in the whole bitmap.
50 	 */
51 	unsigned int depth;
52 
53 	/**
54 	 * @shift: log2(number of bits used per word)
55 	 */
56 	unsigned int shift;
57 
58 	/**
59 	 * @map_nr: Number of words (cachelines) being used for the bitmap.
60 	 */
61 	unsigned int map_nr;
62 
63 	/**
64 	 * @round_robin: Allocate bits in strict round-robin order.
65 	 */
66 	bool round_robin;
67 
68 	/**
69 	 * @map: Allocated bitmap.
70 	 */
71 	struct sbitmap_word *map;
72 
73 	/*
74 	 * @alloc_hint: Cache of last successfully allocated or freed bit.
75 	 *
76 	 * This is per-cpu, which allows multiple users to stick to different
77 	 * cachelines until the map is exhausted.
78 	 */
79 	unsigned int __percpu *alloc_hint;
80 };
81 
82 #define SBQ_WAIT_QUEUES 8
83 #define SBQ_WAKE_BATCH 8
84 
85 /**
86  * struct sbq_wait_state - Wait queue in a &struct sbitmap_queue.
87  */
88 struct sbq_wait_state {
89 	/**
90 	 * @wait: Wait queue.
91 	 */
92 	wait_queue_head_t wait;
93 } ____cacheline_aligned_in_smp;
94 
95 /**
96  * struct sbitmap_queue - Scalable bitmap with the added ability to wait on free
97  * bits.
98  *
99  * A &struct sbitmap_queue uses multiple wait queues and rolling wakeups to
100  * avoid contention on the wait queue spinlock. This ensures that we don't hit a
101  * scalability wall when we run out of free bits and have to start putting tasks
102  * to sleep.
103  */
104 struct sbitmap_queue {
105 	/**
106 	 * @sb: Scalable bitmap.
107 	 */
108 	struct sbitmap sb;
109 
110 	/**
111 	 * @wake_batch: Number of bits which must be freed before we wake up any
112 	 * waiters.
113 	 */
114 	unsigned int wake_batch;
115 
116 	/**
117 	 * @wake_index: Next wait queue in @ws to wake up.
118 	 */
119 	atomic_t wake_index;
120 
121 	/**
122 	 * @ws: Wait queues.
123 	 */
124 	struct sbq_wait_state *ws;
125 
126 	/*
127 	 * @ws_active: count of currently active ws waitqueues
128 	 */
129 	atomic_t ws_active;
130 
131 	/**
132 	 * @min_shallow_depth: The minimum shallow depth which may be passed to
133 	 * sbitmap_queue_get_shallow()
134 	 */
135 	unsigned int min_shallow_depth;
136 
137 	/**
138 	 * @completion_cnt: Number of bits cleared passed to the
139 	 * wakeup function.
140 	 */
141 	atomic_t completion_cnt;
142 
143 	/**
144 	 * @wakeup_cnt: Number of thread wake ups issued.
145 	 */
146 	atomic_t wakeup_cnt;
147 };
148 
149 /**
150  * sbitmap_init_node() - Initialize a &struct sbitmap on a specific memory node.
151  * @sb: Bitmap to initialize.
152  * @depth: Number of bits to allocate.
153  * @shift: Use 2^@shift bits per word in the bitmap; if a negative number if
154  *         given, a good default is chosen.
155  * @flags: Allocation flags.
156  * @node: Memory node to allocate on.
157  * @round_robin: If true, be stricter about allocation order; always allocate
158  *               starting from the last allocated bit. This is less efficient
159  *               than the default behavior (false).
160  * @alloc_hint: If true, apply percpu hint for where to start searching for
161  *              a free bit.
162  *
163  * Return: Zero on success or negative errno on failure.
164  */
165 int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
166 		      gfp_t flags, int node, bool round_robin, bool alloc_hint);
167 
168 /* sbitmap internal helper */
__map_depth(const struct sbitmap * sb,int index)169 static inline unsigned int __map_depth(const struct sbitmap *sb, int index)
170 {
171 	if (index == sb->map_nr - 1)
172 		return sb->depth - (index << sb->shift);
173 	return 1U << sb->shift;
174 }
175 
176 /**
177  * sbitmap_free() - Free memory used by a &struct sbitmap.
178  * @sb: Bitmap to free.
179  */
sbitmap_free(struct sbitmap * sb)180 static inline void sbitmap_free(struct sbitmap *sb)
181 {
182 	free_percpu(sb->alloc_hint);
183 	kvfree(sb->map);
184 	sb->map = NULL;
185 }
186 
187 /**
188  * sbitmap_resize() - Resize a &struct sbitmap.
189  * @sb: Bitmap to resize.
190  * @depth: New number of bits to resize to.
191  *
192  * Doesn't reallocate anything. It's up to the caller to ensure that the new
193  * depth doesn't exceed the depth that the sb was initialized with.
194  */
195 void sbitmap_resize(struct sbitmap *sb, unsigned int depth);
196 
197 /**
198  * sbitmap_get() - Try to allocate a free bit from a &struct sbitmap.
199  * @sb: Bitmap to allocate from.
200  *
201  * This operation provides acquire barrier semantics if it succeeds.
202  *
203  * Return: Non-negative allocated bit number if successful, -1 otherwise.
204  */
205 int sbitmap_get(struct sbitmap *sb);
206 
207 /**
208  * sbitmap_get_shallow() - Try to allocate a free bit from a &struct sbitmap,
209  * limiting the depth used from each word.
210  * @sb: Bitmap to allocate from.
211  * @shallow_depth: The maximum number of bits to allocate from a single word.
212  *
213  * This rather specific operation allows for having multiple users with
214  * different allocation limits. E.g., there can be a high-priority class that
215  * uses sbitmap_get() and a low-priority class that uses sbitmap_get_shallow()
216  * with a @shallow_depth of (1 << (@sb->shift - 1)). Then, the low-priority
217  * class can only allocate half of the total bits in the bitmap, preventing it
218  * from starving out the high-priority class.
219  *
220  * Return: Non-negative allocated bit number if successful, -1 otherwise.
221  */
222 int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth);
223 
224 /**
225  * sbitmap_any_bit_set() - Check for a set bit in a &struct sbitmap.
226  * @sb: Bitmap to check.
227  *
228  * Return: true if any bit in the bitmap is set, false otherwise.
229  */
230 bool sbitmap_any_bit_set(const struct sbitmap *sb);
231 
232 #define SB_NR_TO_INDEX(sb, bitnr) ((bitnr) >> (sb)->shift)
233 #define SB_NR_TO_BIT(sb, bitnr) ((bitnr) & ((1U << (sb)->shift) - 1U))
234 
235 typedef bool (*sb_for_each_fn)(struct sbitmap *, unsigned int, void *);
236 
237 /**
238  * __sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap.
239  * @start: Where to start the iteration.
240  * @sb: Bitmap to iterate over.
241  * @fn: Callback. Should return true to continue or false to break early.
242  * @data: Pointer to pass to callback.
243  *
244  * This is inline even though it's non-trivial so that the function calls to the
245  * callback will hopefully get optimized away.
246  */
__sbitmap_for_each_set(struct sbitmap * sb,unsigned int start,sb_for_each_fn fn,void * data)247 static inline void __sbitmap_for_each_set(struct sbitmap *sb,
248 					  unsigned int start,
249 					  sb_for_each_fn fn, void *data)
250 {
251 	unsigned int index;
252 	unsigned int nr;
253 	unsigned int scanned = 0;
254 
255 	if (start >= sb->depth)
256 		start = 0;
257 	index = SB_NR_TO_INDEX(sb, start);
258 	nr = SB_NR_TO_BIT(sb, start);
259 
260 	while (scanned < sb->depth) {
261 		unsigned long word;
262 		unsigned int depth = min_t(unsigned int,
263 					   __map_depth(sb, index) - nr,
264 					   sb->depth - scanned);
265 
266 		scanned += depth;
267 		word = sb->map[index].word & ~sb->map[index].cleared;
268 		if (!word)
269 			goto next;
270 
271 		/*
272 		 * On the first iteration of the outer loop, we need to add the
273 		 * bit offset back to the size of the word for find_next_bit().
274 		 * On all other iterations, nr is zero, so this is a noop.
275 		 */
276 		depth += nr;
277 		while (1) {
278 			nr = find_next_bit(&word, depth, nr);
279 			if (nr >= depth)
280 				break;
281 			if (!fn(sb, (index << sb->shift) + nr, data))
282 				return;
283 
284 			nr++;
285 		}
286 next:
287 		nr = 0;
288 		if (++index >= sb->map_nr)
289 			index = 0;
290 	}
291 }
292 
293 /**
294  * sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap.
295  * @sb: Bitmap to iterate over.
296  * @fn: Callback. Should return true to continue or false to break early.
297  * @data: Pointer to pass to callback.
298  */
sbitmap_for_each_set(struct sbitmap * sb,sb_for_each_fn fn,void * data)299 static inline void sbitmap_for_each_set(struct sbitmap *sb, sb_for_each_fn fn,
300 					void *data)
301 {
302 	__sbitmap_for_each_set(sb, 0, fn, data);
303 }
304 
__sbitmap_word(struct sbitmap * sb,unsigned int bitnr)305 static inline unsigned long *__sbitmap_word(struct sbitmap *sb,
306 					    unsigned int bitnr)
307 {
308 	return &sb->map[SB_NR_TO_INDEX(sb, bitnr)].word;
309 }
310 
311 /* Helpers equivalent to the operations in asm/bitops.h and linux/bitmap.h */
312 
sbitmap_set_bit(struct sbitmap * sb,unsigned int bitnr)313 static inline void sbitmap_set_bit(struct sbitmap *sb, unsigned int bitnr)
314 {
315 	set_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr));
316 }
317 
sbitmap_clear_bit(struct sbitmap * sb,unsigned int bitnr)318 static inline void sbitmap_clear_bit(struct sbitmap *sb, unsigned int bitnr)
319 {
320 	clear_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr));
321 }
322 
323 /*
324  * This one is special, since it doesn't actually clear the bit, rather it
325  * sets the corresponding bit in the ->cleared mask instead. Paired with
326  * the caller doing sbitmap_deferred_clear() if a given index is full, which
327  * will clear the previously freed entries in the corresponding ->word.
328  */
sbitmap_deferred_clear_bit(struct sbitmap * sb,unsigned int bitnr)329 static inline void sbitmap_deferred_clear_bit(struct sbitmap *sb, unsigned int bitnr)
330 {
331 	unsigned long *addr = &sb->map[SB_NR_TO_INDEX(sb, bitnr)].cleared;
332 
333 	set_bit(SB_NR_TO_BIT(sb, bitnr), addr);
334 }
335 
336 /*
337  * Pair of sbitmap_get, and this one applies both cleared bit and
338  * allocation hint.
339  */
sbitmap_put(struct sbitmap * sb,unsigned int bitnr)340 static inline void sbitmap_put(struct sbitmap *sb, unsigned int bitnr)
341 {
342 	sbitmap_deferred_clear_bit(sb, bitnr);
343 
344 	if (likely(sb->alloc_hint && !sb->round_robin && bitnr < sb->depth))
345 		*raw_cpu_ptr(sb->alloc_hint) = bitnr;
346 }
347 
sbitmap_test_bit(struct sbitmap * sb,unsigned int bitnr)348 static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr)
349 {
350 	return test_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr));
351 }
352 
sbitmap_calculate_shift(unsigned int depth)353 static inline int sbitmap_calculate_shift(unsigned int depth)
354 {
355 	int	shift = ilog2(BITS_PER_LONG);
356 
357 	/*
358 	 * If the bitmap is small, shrink the number of bits per word so
359 	 * we spread over a few cachelines, at least. If less than 4
360 	 * bits, just forget about it, it's not going to work optimally
361 	 * anyway.
362 	 */
363 	if (depth >= 4) {
364 		while ((4U << shift) > depth)
365 			shift--;
366 	}
367 
368 	return shift;
369 }
370 
371 /**
372  * sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file.
373  * @sb: Bitmap to show.
374  * @m: struct seq_file to write to.
375  *
376  * This is intended for debugging. The format may change at any time.
377  */
378 void sbitmap_show(struct sbitmap *sb, struct seq_file *m);
379 
380 
381 /**
382  * sbitmap_weight() - Return how many set and not cleared bits in a &struct
383  * sbitmap.
384  * @sb: Bitmap to check.
385  *
386  * Return: How many set and not cleared bits set
387  */
388 unsigned int sbitmap_weight(const struct sbitmap *sb);
389 
390 /**
391  * sbitmap_bitmap_show() - Write a hex dump of a &struct sbitmap to a &struct
392  * seq_file.
393  * @sb: Bitmap to show.
394  * @m: struct seq_file to write to.
395  *
396  * This is intended for debugging. The output isn't guaranteed to be internally
397  * consistent.
398  */
399 void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m);
400 
401 /**
402  * sbitmap_queue_init_node() - Initialize a &struct sbitmap_queue on a specific
403  * memory node.
404  * @sbq: Bitmap queue to initialize.
405  * @depth: See sbitmap_init_node().
406  * @shift: See sbitmap_init_node().
407  * @round_robin: See sbitmap_get().
408  * @flags: Allocation flags.
409  * @node: Memory node to allocate on.
410  *
411  * Return: Zero on success or negative errno on failure.
412  */
413 int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth,
414 			    int shift, bool round_robin, gfp_t flags, int node);
415 
416 /**
417  * sbitmap_queue_free() - Free memory used by a &struct sbitmap_queue.
418  *
419  * @sbq: Bitmap queue to free.
420  */
sbitmap_queue_free(struct sbitmap_queue * sbq)421 static inline void sbitmap_queue_free(struct sbitmap_queue *sbq)
422 {
423 	kfree(sbq->ws);
424 	sbitmap_free(&sbq->sb);
425 }
426 
427 /**
428  * sbitmap_queue_recalculate_wake_batch() - Recalculate wake batch
429  * @sbq: Bitmap queue to recalculate wake batch.
430  * @users: Number of shares.
431  *
432  * Like sbitmap_queue_update_wake_batch(), this will calculate wake batch
433  * by depth. This interface is for HCTX shared tags or queue shared tags.
434  */
435 void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq,
436 					    unsigned int users);
437 
438 /**
439  * sbitmap_queue_resize() - Resize a &struct sbitmap_queue.
440  * @sbq: Bitmap queue to resize.
441  * @depth: New number of bits to resize to.
442  *
443  * Like sbitmap_resize(), this doesn't reallocate anything. It has to do
444  * some extra work on the &struct sbitmap_queue, so it's not safe to just
445  * resize the underlying &struct sbitmap.
446  */
447 void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth);
448 
449 /**
450  * __sbitmap_queue_get() - Try to allocate a free bit from a &struct
451  * sbitmap_queue with preemption already disabled.
452  * @sbq: Bitmap queue to allocate from.
453  *
454  * Return: Non-negative allocated bit number if successful, -1 otherwise.
455  */
456 int __sbitmap_queue_get(struct sbitmap_queue *sbq);
457 
458 /**
459  * __sbitmap_queue_get_batch() - Try to allocate a batch of free bits
460  * @sbq: Bitmap queue to allocate from.
461  * @nr_tags: number of tags requested
462  * @offset: offset to add to returned bits
463  *
464  * Return: Mask of allocated tags, 0 if none are found. Each tag allocated is
465  * a bit in the mask returned, and the caller must add @offset to the value to
466  * get the absolute tag value.
467  */
468 unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
469 					unsigned int *offset);
470 
471 /**
472  * sbitmap_queue_get_shallow() - Try to allocate a free bit from a &struct
473  * sbitmap_queue, limiting the depth used from each word, with preemption
474  * already disabled.
475  * @sbq: Bitmap queue to allocate from.
476  * @shallow_depth: The maximum number of bits to allocate from a single word.
477  * See sbitmap_get_shallow().
478  *
479  * If you call this, make sure to call sbitmap_queue_min_shallow_depth() after
480  * initializing @sbq.
481  *
482  * Return: Non-negative allocated bit number if successful, -1 otherwise.
483  */
484 int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
485 			      unsigned int shallow_depth);
486 
487 /**
488  * sbitmap_queue_get() - Try to allocate a free bit from a &struct
489  * sbitmap_queue.
490  * @sbq: Bitmap queue to allocate from.
491  * @cpu: Output parameter; will contain the CPU we ran on (e.g., to be passed to
492  *       sbitmap_queue_clear()).
493  *
494  * Return: Non-negative allocated bit number if successful, -1 otherwise.
495  */
sbitmap_queue_get(struct sbitmap_queue * sbq,unsigned int * cpu)496 static inline int sbitmap_queue_get(struct sbitmap_queue *sbq,
497 				    unsigned int *cpu)
498 {
499 	int nr;
500 
501 	*cpu = get_cpu();
502 	nr = __sbitmap_queue_get(sbq);
503 	put_cpu();
504 	return nr;
505 }
506 
507 /**
508  * sbitmap_queue_min_shallow_depth() - Inform a &struct sbitmap_queue of the
509  * minimum shallow depth that will be used.
510  * @sbq: Bitmap queue in question.
511  * @min_shallow_depth: The minimum shallow depth that will be passed to
512  * sbitmap_queue_get_shallow() or __sbitmap_queue_get_shallow().
513  *
514  * sbitmap_queue_clear() batches wakeups as an optimization. The batch size
515  * depends on the depth of the bitmap. Since the shallow allocation functions
516  * effectively operate with a different depth, the shallow depth must be taken
517  * into account when calculating the batch size. This function must be called
518  * with the minimum shallow depth that will be used. Failure to do so can result
519  * in missed wakeups.
520  */
521 void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq,
522 				     unsigned int min_shallow_depth);
523 
524 /**
525  * sbitmap_queue_clear() - Free an allocated bit and wake up waiters on a
526  * &struct sbitmap_queue.
527  * @sbq: Bitmap to free from.
528  * @nr: Bit number to free.
529  * @cpu: CPU the bit was allocated on.
530  */
531 void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
532 			 unsigned int cpu);
533 
534 /**
535  * sbitmap_queue_clear_batch() - Free a batch of allocated bits
536  * &struct sbitmap_queue.
537  * @sbq: Bitmap to free from.
538  * @offset: offset for each tag in array
539  * @tags: array of tags
540  * @nr_tags: number of tags in array
541  */
542 void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
543 				int *tags, int nr_tags);
544 
sbq_index_inc(int index)545 static inline int sbq_index_inc(int index)
546 {
547 	return (index + 1) & (SBQ_WAIT_QUEUES - 1);
548 }
549 
sbq_index_atomic_inc(atomic_t * index)550 static inline void sbq_index_atomic_inc(atomic_t *index)
551 {
552 	int old = atomic_read(index);
553 	int new = sbq_index_inc(old);
554 	atomic_cmpxchg(index, old, new);
555 }
556 
557 /**
558  * sbq_wait_ptr() - Get the next wait queue to use for a &struct
559  * sbitmap_queue.
560  * @sbq: Bitmap queue to wait on.
561  * @wait_index: A counter per "user" of @sbq.
562  */
sbq_wait_ptr(struct sbitmap_queue * sbq,atomic_t * wait_index)563 static inline struct sbq_wait_state *sbq_wait_ptr(struct sbitmap_queue *sbq,
564 						  atomic_t *wait_index)
565 {
566 	struct sbq_wait_state *ws;
567 
568 	ws = &sbq->ws[atomic_read(wait_index)];
569 	sbq_index_atomic_inc(wait_index);
570 	return ws;
571 }
572 
573 /**
574  * sbitmap_queue_wake_all() - Wake up everything waiting on a &struct
575  * sbitmap_queue.
576  * @sbq: Bitmap queue to wake up.
577  */
578 void sbitmap_queue_wake_all(struct sbitmap_queue *sbq);
579 
580 /**
581  * sbitmap_queue_wake_up() - Wake up some of waiters in one waitqueue
582  * on a &struct sbitmap_queue.
583  * @sbq: Bitmap queue to wake up.
584  * @nr: Number of bits cleared.
585  */
586 void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr);
587 
588 /**
589  * sbitmap_queue_show() - Dump &struct sbitmap_queue information to a &struct
590  * seq_file.
591  * @sbq: Bitmap queue to show.
592  * @m: struct seq_file to write to.
593  *
594  * This is intended for debugging. The format may change at any time.
595  */
596 void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m);
597 
598 struct sbq_wait {
599 	struct sbitmap_queue *sbq;	/* if set, sbq_wait is accounted */
600 	struct wait_queue_entry wait;
601 };
602 
603 #define DEFINE_SBQ_WAIT(name)							\
604 	struct sbq_wait name = {						\
605 		.sbq = NULL,							\
606 		.wait = {							\
607 			.private	= current,				\
608 			.func		= autoremove_wake_function,		\
609 			.entry		= LIST_HEAD_INIT((name).wait.entry),	\
610 		}								\
611 	}
612 
613 /*
614  * Wrapper around prepare_to_wait_exclusive(), which maintains some extra
615  * internal state.
616  */
617 void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,
618 				struct sbq_wait_state *ws,
619 				struct sbq_wait *sbq_wait, int state);
620 
621 /*
622  * Must be paired with sbitmap_prepare_to_wait().
623  */
624 void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,
625 				struct sbq_wait *sbq_wait);
626 
627 /*
628  * Wrapper around add_wait_queue(), which maintains some extra internal state
629  */
630 void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
631 			    struct sbq_wait_state *ws,
632 			    struct sbq_wait *sbq_wait);
633 
634 /*
635  * Must be paired with sbitmap_add_wait_queue()
636  */
637 void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait);
638 
639 #endif /* __LINUX_SCALE_BITMAP_H */
640