Re: [CRYPTO]: Only reschedule if !in_atomic()

[Bill Davidsen <davidsen@tmr.com>]

Andrew Morton wrote:
> Herbert Xu <herbert@gondor.apana.org.au> wrote:
> 
>>Perhaps we should code this into the crypto API instead? For instance,
>> we can have a tfm flag that says whether we can sleep or not.
> 
> 
> Are you sure it's actually needed? Have significant scheduling latencies
> actually been observed?
> 
> Bear in mind that anyone who cares a lot about latency will be running
> CONFIG_PREEMPT kernels, in which case the whole thing is redundant anyway. 
> I generally take the position that if we're going to put a scheduling point
> into a non-premept kernel then it'd better be for a pretty bad latency
> point - more than 10 milliseconds, say.
> 
People do run crypto on old slow machines, and also laptops configured 
to use as little power as possible. I wouldn't be surprised if latencies 
got in the >10ms range pretty regularly on some systems which are pretty 
mainstream.

Just my read on it, if a flag will prevent deadlock without relying on 
callers doing the right thing, that's probably a desirable change WRT 
future stability.