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linux-next/fs/btrfs/misc.h
David Sterba 79c8264e44 btrfs: add 64bit safe helper for power of two checks
As is_power_of_two takes unsigned long, it's not safe on 32bit
architectures, but we could pass any u64 value in seveal places. Add a
separate helper and also an alias that better expresses the purpose for
which the helper is used.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:50 +01:00

62 lines
1.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef BTRFS_MISC_H
#define BTRFS_MISC_H
#include <linux/sched.h>
#include <linux/wait.h>
#include <asm/div64.h>
#define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
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 div_factor(u64 num, int factor)
{
if (factor == 10)
return num;
num *= factor;
return div_u64(num, 10);
}
static inline u64 div_factor_fine(u64 num, int factor)
{
if (factor == 100)
return num;
num *= factor;
return div_u64(num, 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);
}
#endif