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SubjectRe: Clarification of allowed context for crypto routines
Andrey Borzenkov <arvidjaar@mail.ru> wrote:
>
> As I can understand, user context requirement is due to potential for
> setkey to sleep (although it appears, that currently the only module
> that can sleep is shash which is calling kmalloc with GFP_KERNEL). Is it
> correct?

Yep.

> But where is the difference between hard and softirq contexts? I fail to
> see any technical reason for this requirement.

The reasons are two-fold:

1) Crypto operations are so slow in general that if you did them
in hard IRQ context it would just be wrong;

2) The highmem primitives we use are currently softirq only. We
could make them work for hardirq as well, but because of 1) we
didn't.

Cheers,
--
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