linux-kernel - Re: [dm-devel] [PATCH 4/4] crypto: fix the drivers that don't respect CRYPTO_TFM_REQ_MAY

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Date:   Tue, 16 Jun 2020 10:50:22 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     Mikulas Patocka <mpatocka@...hat.com>
Cc:     Herbert Xu <herbert@...dor.apana.org.au>,
        Mike Snitzer <msnitzer@...hat.com>,
        linux-kernel@...r.kernel.org, dm-devel@...hat.com,
        linux-crypto@...r.kernel.org,
        "David S. Miller" <davem@...emloft.net>,
        Milan Broz <mbroz@...hat.com>
Subject: Re: [dm-devel] [PATCH 4/4] crypto: fix the drivers that don't
 respect CRYPTO_TFM_REQ_MAY_SLEEP

On Tue, Jun 16, 2020 at 11:02:50AM -0400, Mikulas Patocka wrote:
> Fix the crypto drivers that don't respect CRYPTO_TFM_REQ_MAY_SLEEP. If
> CRYPTO_TFM_REQ_MAY_SLEEP is not set, the driver must not do allocation
> that sleeps.
> 
> Signed-off-by: Mikulas Patocka <mpatocka@...hat.com>

I think you need to split this up per driver with a proper explanation and a
"Fixes:" tag for each driver.

Also, these bugs should have been detected by the crypto self-tests already,
since they test having preemption disabled and CRYPTO_TFM_REQ_MAY_SLEEP cleared.
Can you double check whether these are all valid fixes?  One thing to watch out
for is that CRYPTO_TFM_REQ_MAY_SLEEP only applies to the function call like
crypto_skcipher_encrypt() itself.  If the implementation is asynchronous and the
request gets processed in the background (i.e. if crypto_skcipher_encrypt()
returns -EINPROGRESS), the background work doesn't have to honor
CRYPTO_TFM_REQ_MAY_SLEEP.

- Eric