fs/btrfs/misc.h

   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
  13 static 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
  23 static 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
  35 static 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
  43 static 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 */
  52 static inline bool is_power_of_two_u64(u64 n)
  53 {
  54         return n != 0 && (n & (n - 1)) == 0;
  55 }
  56
  57 static 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  */
  68 struct rb_simple_node {
  69         struct rb_node rb_node;
  70         u64 bytenr;
  71 };
  72
  73 static 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
  91 static 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