xref: /kernel/linux/linux-5.10/fs/btrfs/misc.h (revision 8c2ecf20) 
1/* SPDX-License-Identifier: GPL-2.0 */
2
3#ifndef BTRFS_MISC_H
4#define BTRFS_MISC_H
5
6#include <linux/sched.h>
7#include <linux/wait.h>
8#include <asm/div64.h>
9#include <linux/rbtree.h>
10
11#define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
12
13static inline void cond_wake_up(struct wait_queue_head *wq)
14{
15	/*
16	 * This implies a full smp_mb barrier, see comments for
17	 * waitqueue_active why.
18	 */
19	if (wq_has_sleeper(wq))
20		wake_up(wq);
21}
22
23static inline void cond_wake_up_nomb(struct wait_queue_head *wq)
24{
25	/*
26	 * Special case for conditional wakeup where the barrier required for
27	 * waitqueue_active is implied by some of the preceding code. Eg. one
28	 * of such atomic operations (atomic_dec_and_return, ...), or a
29	 * unlock/lock sequence, etc.
30	 */
31	if (waitqueue_active(wq))
32		wake_up(wq);
33}
34
35static inline u64 div_factor(u64 num, int factor)
36{
37	if (factor == 10)
38		return num;
39	num *= factor;
40	return div_u64(num, 10);
41}
42
43static inline u64 div_factor_fine(u64 num, int factor)
44{
45	if (factor == 100)
46		return num;
47	num *= factor;
48	return div_u64(num, 100);
49}
50
51/* Copy of is_power_of_two that is 64bit safe */
52static inline bool is_power_of_two_u64(u64 n)
53{
54	return n != 0 && (n & (n - 1)) == 0;
55}
56
57static inline bool has_single_bit_set(u64 n)
58{
59	return is_power_of_two_u64(n);
60}
61
62/*
63 * Simple bytenr based rb_tree relate structures
64 *
65 * Any structure wants to use bytenr as single search index should have their
66 * structure start with these members.
67 */
68struct rb_simple_node {
69	struct rb_node rb_node;
70	u64 bytenr;
71};
72
73static inline struct rb_node *rb_simple_search(struct rb_root *root, u64 bytenr)
74{
75	struct rb_node *node = root->rb_node;
76	struct rb_simple_node *entry;
77
78	while (node) {
79		entry = rb_entry(node, struct rb_simple_node, rb_node);
80
81		if (bytenr < entry->bytenr)
82			node = node->rb_left;
83		else if (bytenr > entry->bytenr)
84			node = node->rb_right;
85		else
86			return node;
87	}
88	return NULL;
89}
90
91static inline struct rb_node *rb_simple_insert(struct rb_root *root, u64 bytenr,
92					       struct rb_node *node)
93{
94	struct rb_node **p = &root->rb_node;
95	struct rb_node *parent = NULL;
96	struct rb_simple_node *entry;
97
98	while (*p) {
99		parent = *p;
100		entry = rb_entry(parent, struct rb_simple_node, rb_node);
101
102		if (bytenr < entry->bytenr)
103			p = &(*p)->rb_left;
104		else if (bytenr > entry->bytenr)
105			p = &(*p)->rb_right;
106		else
107			return parent;
108	}
109
110	rb_link_node(node, parent, p);
111	rb_insert_color(node, root);
112	return NULL;
113}
114
115#endif
116