* [PATCH] random: only wake up writers after zap if threshold was passed
@ 2022-02-22 13:05 Jason A. Donenfeld
2022-02-24 7:48 ` Dominik Brodowski
0 siblings, 1 reply; 2+ messages in thread
From: Jason A. Donenfeld @ 2022-02-22 13:05 UTC (permalink / raw)
To: linux-kernel; +Cc: Jason A. Donenfeld, Dominik Brodowski, Theodore Ts'o
The only time that we need to wake up /dev/random writers on
RNDCLEARPOOL/RNDZAPPOOL is when we're changing from a value that is
greater than or equal to POOL_MIN_BITS to zero, because if we're
changing from below POOL_MIN_BITS to zero, the writers are already
unblocked.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
drivers/char/random.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index a4dedeea35e9..536237a0f073 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1582,7 +1582,7 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
*/
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (xchg(&input_pool.entropy_count, 0)) {
+ if (xchg(&input_pool.entropy_count, 0) >= POOL_MIN_BITS) {
wake_up_interruptible(&random_write_wait);
kill_fasync(&fasync, SIGIO, POLL_OUT);
}
--
2.35.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] random: only wake up writers after zap if threshold was passed
2022-02-22 13:05 [PATCH] random: only wake up writers after zap if threshold was passed Jason A. Donenfeld
@ 2022-02-24 7:48 ` Dominik Brodowski
0 siblings, 0 replies; 2+ messages in thread
From: Dominik Brodowski @ 2022-02-24 7:48 UTC (permalink / raw)
To: Jason A. Donenfeld; +Cc: linux-kernel, Theodore Ts'o
Am Tue, Feb 22, 2022 at 02:05:03PM +0100 schrieb Jason A. Donenfeld:
> The only time that we need to wake up /dev/random writers on
> RNDCLEARPOOL/RNDZAPPOOL is when we're changing from a value that is
> greater than or equal to POOL_MIN_BITS to zero, because if we're
> changing from below POOL_MIN_BITS to zero, the writers are already
> unblocked.
>
> Cc: Dominik Brodowski <linux@dominikbrodowski.net>
> Cc: Theodore Ts'o <tytso@mit.edu>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Thanks,
Dominik
^ permalink raw reply [flat|nested] 2+ messages in thread
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