Re: [PATCH v3] random: unify cycles_t and jiffies usage and types

[Dominik Brodowski <linux@dominikbrodowski.net>]

Am Fri, Feb 25, 2022 at 02:44:08PM +0100 schrieb Jason A. Donenfeld:
> random_get_entropy() returns a cycles_t, not an unsigned long, which is
> sometimes 64 bits on various 32-bit platforms, including x86.
> Conversely, jiffies is always unsigned long. This commit fixes things to
> use cycles_t for fields that use random_get_entropy(), named "cycles",
> and unsigned long for fields that use jiffies, named "now". It's also
> good to mix in a cycles_t and a jiffies in the same way for both
> add_device_randomness and add_timer_randomness, rather than using xor in
> one case. Finally, we unify the order of these volatile reads, always
> reading the more precise cycles counter, and then jiffies, so that the
> cycle counter is as close to the event as possible.
> 
> Cc: Theodore Ts'o <tytso@mit.edu>
> Cc: Dominik Brodowski <linux@dominikbrodowski.net>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

	Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>

Thanks,
	Dominik