[dm-devel] [PATCH 4/4] crypto: fix the drivers that don't respect CRYPTO_TFM_REQ_MAY_SLEEP

[Eric Biggers]

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 at redhat.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