fs/btrfs/misc.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002
0003 #ifndef BTRFS_MISC_H
0004 #define BTRFS_MISC_H
0005
0006 #include <linux/sched.h>
0007 #include <linux/wait.h>
0008 #include <linux/math64.h>
0009 #include <linux/rbtree.h>
0010
0011 #define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
0012
0013 static inline void cond_wake_up(struct wait_queue_head *wq)
0014 {
0015     /*
0016      * This implies a full smp_mb barrier, see comments for
0017      * waitqueue_active why.
0018      */
0019     if (wq_has_sleeper(wq))
0020         wake_up(wq);
0021 }
0022
0023 static inline void cond_wake_up_nomb(struct wait_queue_head *wq)
0024 {
0025     /*
0026      * Special case for conditional wakeup where the barrier required for
0027      * waitqueue_active is implied by some of the preceding code. Eg. one
0028      * of such atomic operations (atomic_dec_and_return, ...), or a
0029      * unlock/lock sequence, etc.
0030      */
0031     if (waitqueue_active(wq))
0032         wake_up(wq);
0033 }
0034
0035 static inline u64 div_factor(u64 num, int factor)
0036 {
0037     if (factor == 10)
0038         return num;
0039     num *= factor;
0040     return div_u64(num, 10);
0041 }
0042
0043 static inline u64 div_factor_fine(u64 num, int factor)
0044 {
0045     if (factor == 100)
0046         return num;
0047     num *= factor;
0048     return div_u64(num, 100);
0049 }
0050
0051 /* Copy of is_power_of_two that is 64bit safe */
0052 static inline bool is_power_of_two_u64(u64 n)
0053 {
0054     return n != 0 && (n & (n - 1)) == 0;
0055 }
0056
0057 static inline bool has_single_bit_set(u64 n)
0058 {
0059     return is_power_of_two_u64(n);
0060 }
0061
0062 /*
0063  * Simple bytenr based rb_tree relate structures
0064  *
0065  * Any structure wants to use bytenr as single search index should have their
0066  * structure start with these members.
0067  */
0068 struct rb_simple_node {
0069     struct rb_node rb_node;
0070     u64 bytenr;
0071 };
0072
0073 static inline struct rb_node *rb_simple_search(struct rb_root *root, u64 bytenr)
0074 {
0075     struct rb_node *node = root->rb_node;
0076     struct rb_simple_node *entry;
0077
0078     while (node) {
0079         entry = rb_entry(node, struct rb_simple_node, rb_node);
0080
0081         if (bytenr < entry->bytenr)
0082             node = node->rb_left;
0083         else if (bytenr > entry->bytenr)
0084             node = node->rb_right;
0085         else
0086             return node;
0087     }
0088     return NULL;
0089 }
0090
0091 static inline struct rb_node *rb_simple_insert(struct rb_root *root, u64 bytenr,
0092                            struct rb_node *node)
0093 {
0094     struct rb_node **p = &root->rb_node;
0095     struct rb_node *parent = NULL;
0096     struct rb_simple_node *entry;
0097
0098     while (*p) {
0099         parent = *p;
0100         entry = rb_entry(parent, struct rb_simple_node, rb_node);
0101
0102         if (bytenr < entry->bytenr)
0103             p = &(*p)->rb_left;
0104         else if (bytenr > entry->bytenr)
0105             p = &(*p)->rb_right;
0106         else
0107             return parent;
0108     }
0109
0110     rb_link_node(node, parent, p);
0111     rb_insert_color(node, root);
0112     return NULL;
0113 }
0114
0115 #endif