mirror_zfs/include/os/linux/spl/sys/random.h
Alexander Motin 29274c9f6d
Optimize small random numbers generation
In all places except two spa_get_random() is used for small values,
and the consumers do not require well seeded high quality values.
Switch those two exceptions directly to random_get_pseudo_bytes()
and optimize spa_get_random(), renaming it to random_in_range(),
since it is not related to SPA or ZFS in general.

On FreeBSD directly map random_in_range() to new prng32_bounded() KPI
added in FreeBSD 13.  On Linux and in user-space just reduce the type
used to uint32_t to avoid more expensive 64bit division.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #12183
2021-06-22 17:35:23 -06:00

55 lines
1.5 KiB
C

/*
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _SPL_RANDOM_H
#define _SPL_RANDOM_H
#include <linux/module.h>
#include <linux/random.h>
static __inline__ int
random_get_bytes(uint8_t *ptr, size_t len)
{
get_random_bytes((void *)ptr, (int)len);
return (0);
}
extern int random_get_pseudo_bytes(uint8_t *ptr, size_t len);
static __inline__ uint32_t
random_in_range(uint32_t range)
{
uint32_t r;
ASSERT(range != 0);
if (range == 1)
return (0);
(void) random_get_pseudo_bytes((void *)&r, sizeof (r));
return (r % range);
}
#endif /* _SPL_RANDOM_H */