From: Peter Zijlstra <peterz@infradead.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Eric Biggers <ebiggers@google.com>
Subject: Re: [PATCH 0/7] crypto: switch to static calls for CRC-T10DIF
Date: Mon, 11 Jan 2021 21:56:48 +0100 [thread overview]
Message-ID: <X/y7kOIJSKQs1FCv@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAMj1kXHLBDUGZbc7dw0bd5K4ecPLmnDYMwrPA7yGzA0VNaJWgw@mail.gmail.com>
On Mon, Jan 11, 2021 at 07:36:20PM +0100, Ard Biesheuvel wrote:
> On Mon, 11 Jan 2021 at 18:27, Ard Biesheuvel <ardb@kernel.org> wrote:
> > On Mon, 11 Jan 2021 at 17:52, Ard Biesheuvel <ardb@kernel.org> wrote:
> > > Special request to Peter to take a look at patch #2, and in particular,
> > > whether synchronize_rcu_tasks() is sufficient to ensure that a module
> > > providing the target of a static call can be unloaded safely.
> >
> > It seems I may have managed to confuse myself slightly here: without
> > an upper bound on the size of the input of the crc_t10dif() routine, I
> > suppose we can never assume that all its callers have finished.
> >
>
> Replying to self again - apologies.
>
> I think this is actually correct after all: synchronize_rcu_tasks()
> guarantees that all tasks have passed through a 'safe state', i.e.,
> voluntary schedule(), return to userland, etc, which guarantees that
> no task could be executing the old static call target after
> synchronize_rcu_tasks() returns.
Right, I think it should work.
My initial question was why you'd want to support the unreg at all.
AFAICT these implementations are tiny, why bother having them as a
module, or if you insist having them as a module, why allowing removal?
next prev parent reply other threads:[~2021-01-11 20:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 16:52 [PATCH 0/7] crypto: switch to static calls for CRC-T10DIF Ard Biesheuvel
2021-01-11 16:52 ` [PATCH 1/7] crypto: crc-t10dif - turn library wrapper for shash into generic library Ard Biesheuvel
2021-01-11 16:52 ` [PATCH 2/7] crypto: lib/crc-t10dif - add static call support for optimized versions Ard Biesheuvel
2021-01-11 16:52 ` [PATCH 3/7] crypto: generic/crc-t10dif - expose both arch and generic shashes Ard Biesheuvel
2021-01-11 16:52 ` [PATCH 4/7] crypto: x86/crc-t10dif - convert to static call library API Ard Biesheuvel
2021-01-12 0:01 ` kernel test robot
2021-01-11 16:52 ` [PATCH 5/7] crypto: arm/crc-t10dif " Ard Biesheuvel
2021-01-11 16:52 ` [PATCH 6/7] crypto: arm64/crc-t10dif - convert to static call API Ard Biesheuvel
2021-01-11 16:52 ` [PATCH 7/7] crypto: powerpc/crc-t10dif " Ard Biesheuvel
2021-01-11 17:27 ` [PATCH 0/7] crypto: switch to static calls for CRC-T10DIF Ard Biesheuvel
2021-01-11 18:36 ` Ard Biesheuvel
2021-01-11 20:56 ` Peter Zijlstra [this message]
2021-01-11 21:01 ` Ard Biesheuvel
2021-01-11 21:05 ` Eric Biggers
2021-01-11 21:31 ` Ard Biesheuvel
2021-01-28 8:19 ` Ard Biesheuvel
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