diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/btrfs/misc.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/fs/btrfs/misc.h b/fs/btrfs/misc.h new file mode 100644 index 0000000000..40f2d9f1a1 --- /dev/null +++ b/fs/btrfs/misc.h @@ -0,0 +1,164 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_MISC_H +#define BTRFS_MISC_H + +#include <linux/sched.h> +#include <linux/wait.h> +#include <linux/math64.h> +#include <linux/rbtree.h> + +/* + * Enumerate bits using enum autoincrement. Define the @name as the n-th bit. + */ +#define ENUM_BIT(name) \ + __ ## name ## _BIT, \ + name = (1U << __ ## name ## _BIT), \ + __ ## name ## _SEQ = __ ## name ## _BIT + +static inline void cond_wake_up(struct wait_queue_head *wq) +{ + /* + * This implies a full smp_mb barrier, see comments for + * waitqueue_active why. + */ + if (wq_has_sleeper(wq)) + wake_up(wq); +} + +static inline void cond_wake_up_nomb(struct wait_queue_head *wq) +{ + /* + * Special case for conditional wakeup where the barrier required for + * waitqueue_active is implied by some of the preceding code. Eg. one + * of such atomic operations (atomic_dec_and_return, ...), or a + * unlock/lock sequence, etc. + */ + if (waitqueue_active(wq)) + wake_up(wq); +} + +static inline u64 mult_perc(u64 num, u32 percent) +{ + return div_u64(num * percent, 100); +} +/* Copy of is_power_of_two that is 64bit safe */ +static inline bool is_power_of_two_u64(u64 n) +{ + return n != 0 && (n & (n - 1)) == 0; +} + +static inline bool has_single_bit_set(u64 n) +{ + return is_power_of_two_u64(n); +} + +/* + * Simple bytenr based rb_tree relate structures + * + * Any structure wants to use bytenr as single search index should have their + * structure start with these members. + */ +struct rb_simple_node { + struct rb_node rb_node; + u64 bytenr; +}; + +static inline struct rb_node *rb_simple_search(struct rb_root *root, u64 bytenr) +{ + struct rb_node *node = root->rb_node; + struct rb_simple_node *entry; + + while (node) { + entry = rb_entry(node, struct rb_simple_node, rb_node); + + if (bytenr < entry->bytenr) + node = node->rb_left; + else if (bytenr > entry->bytenr) + node = node->rb_right; + else + return node; + } + return NULL; +} + +/* + * Search @root from an entry that starts or comes after @bytenr. + * + * @root: the root to search. + * @bytenr: bytenr to search from. + * + * Return the rb_node that start at or after @bytenr. If there is no entry at + * or after @bytner return NULL. + */ +static inline struct rb_node *rb_simple_search_first(struct rb_root *root, + u64 bytenr) +{ + struct rb_node *node = root->rb_node, *ret = NULL; + struct rb_simple_node *entry, *ret_entry = NULL; + + while (node) { + entry = rb_entry(node, struct rb_simple_node, rb_node); + + if (bytenr < entry->bytenr) { + if (!ret || entry->bytenr < ret_entry->bytenr) { + ret = node; + ret_entry = entry; + } + + node = node->rb_left; + } else if (bytenr > entry->bytenr) { + node = node->rb_right; + } else { + return node; + } + } + + return ret; +} + +static inline struct rb_node *rb_simple_insert(struct rb_root *root, u64 bytenr, + struct rb_node *node) +{ + struct rb_node **p = &root->rb_node; + struct rb_node *parent = NULL; + struct rb_simple_node *entry; + + while (*p) { + parent = *p; + entry = rb_entry(parent, struct rb_simple_node, rb_node); + + if (bytenr < entry->bytenr) + p = &(*p)->rb_left; + else if (bytenr > entry->bytenr) + p = &(*p)->rb_right; + else + return parent; + } + + rb_link_node(node, parent, p); + rb_insert_color(node, root); + return NULL; +} + +static inline bool bitmap_test_range_all_set(const unsigned long *addr, + unsigned long start, + unsigned long nbits) +{ + unsigned long found_zero; + + found_zero = find_next_zero_bit(addr, start + nbits, start); + return (found_zero == start + nbits); +} + +static inline bool bitmap_test_range_all_zero(const unsigned long *addr, + unsigned long start, + unsigned long nbits) +{ + unsigned long found_set; + + found_set = find_next_bit(addr, start + nbits, start); + return (found_set == start + nbits); +} + +#endif |