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From: David Laight <David.Laight@ACULAB.COM>
To: "'Jason A. Donenfeld'" <Jason@zx2c4.com>, Borislav Petkov <bp@suse.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>, Will Deacon <will@kernel.org>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	Mark Rutland <mark.rutland@arm.com>,
	Harald Freudenberger <freude@linux.ibm.com>,
	"Michael Ellerman" <mpe@ellerman.id.au>
Subject: RE: [PATCH v3] random: handle archrandom with multiple longs
Date: Mon, 25 Jul 2022 09:36:34 +0000	[thread overview]
Message-ID: <10561a841a7342c882aabb0fbdbfc762@AcuMS.aculab.com> (raw)
In-Reply-To: <Yt5hwxC1xgvA8Asw@zx2c4.com>

...
> More directly, the reason we don't want to error is because the use case
> has fallbacks meant to handle errors. The cascade looks like this
> (quoting from the other email):
> 
>     unsigned long array[whatever];
>     for (i = 0; i < ARRAY_SIZE(array);) {
>         longs = arch_get_random_seed_longs(&array[i], ARRAY_SIZE(array) - i);
>         if (longs) {
>             i += longs;
>             continue;
>         }
>         longs = arch_get_random_longs(&array[i], ARRAY_SIZE(array) - i);
>         if (longs) {
>             i += longs;
>             continue;
>         }
>         array[i++] = random_get_entropy();
>     }
> 
> It tries to get the best that it can as much as it can, but isn't going
> to block or do anything too nuts for that.

Do you really want to retry the earlier calls that returned no data?

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  reply	other threads:[~2022-07-25  9:36 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-17 11:24 [PATCH] random: handle archrandom in plural words Jason A. Donenfeld
2022-07-17 11:43 ` Jason A. Donenfeld
2022-07-17 20:03   ` [PATCH v2] " Jason A. Donenfeld
2022-07-18  6:31     ` Michael Ellerman
2022-07-18  6:46       ` Gabriel Paubert
2022-07-20  3:03         ` Michael Ellerman
2022-07-19 12:42     ` Mark Rutland
2022-07-19 12:46       ` Jason A. Donenfeld
2022-07-19 13:02         ` [PATCH v3] random: handle archrandom with multiple longs Jason A. Donenfeld
2022-07-19 13:17           ` Mark Rutland
2022-07-19 13:48           ` Catalin Marinas
2022-07-22 12:06           ` Heiko Carstens
2022-07-24 22:47           ` Jason A. Donenfeld
2022-07-25  9:19           ` Borislav Petkov
2022-07-25  9:26             ` Jason A. Donenfeld
2022-07-25  9:36               ` David Laight [this message]
2022-07-25  9:37                 ` Jason A. Donenfeld
2022-07-25 11:10               ` [PATCH] random: discourage use of archrandom outside of rng Jason A. Donenfeld
2022-07-25 11:25                 ` Borislav Petkov
2022-07-25 11:33                 ` Heiko Carstens
2022-07-25 13:02                 ` Mark Rutland
2022-07-25 11:25           ` [PATCH v3] random: handle archrandom with multiple longs Borislav Petkov
2022-08-01 14:46           ` Harald Freudenberger
2022-08-01 14:50             ` Jason A. Donenfeld
2022-07-22  8:08     ` [PATCH v2] random: handle archrandom in plural words Holger Dengler
2022-07-22 11:22       ` Jason A. Donenfeld
2022-08-03 12:01         ` Holger Dengler

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