RE: :Re: [PATCH v2 04/19] crypto: x86/sha - limit FPU preemption

From: Elliott, Robert (Servers)
Date: Thu Oct 13 2022 - 18:42:36 EST




> > diff --git a/arch/x86/crypto/sha1_ssse3_glue.c
...
> > + do {
> > + unsigned int chunk = min(len, FPU_BYTES);
> > +
> > + if (chunk) {
> > + kernel_fpu_begin();
> > + sha1_base_do_update(desc, data, chunk, sha1_xform);
> > + kernel_fpu_end();
> > + }
> > +
> > + len -= chunk;
> > + data += chunk;
> > + } while (len);
>
> 'len' can't be 0 at the beginning of this loop, so the 'if (chunk)' check
> isn't needed. And it wouldn't make sense even if 'len' could be 0, since
> a while loop could just be used in that case.

Thanks, I'll remove that if from all the sha functions, since they do
have that protective check upfront. I'll review the 0 byte handling in
all of them.