Messages in this thread | | | Date | Thu, 4 Jun 2020 15:59:24 +0100 | From | Al Viro <> | Subject | Re: [PATCH RFC] uaccess: user_access_begin_after_access_ok() |
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On Thu, Jun 04, 2020 at 02:10:27PM +0800, Jason Wang wrote:
> > > get_user(flags, desc->flags) > > > smp_rmb() > > > if (flags & VALID) > > > copy_from_user(&adesc, desc, sizeof adesc); > > > > > > this would be a good candidate I think. > > Perhaps, once we get stac/clac out of raw_copy_from_user() (coming cycle, > > probably). BTW, how large is the structure and how is it aligned? > > > Each descriptor is 16 bytes, and 16 bytes aligned.
Won't it be cheaper to grap the entire thing unconditionally? And what does that rmb order, while we are at it - won't all coherency work in terms of entire cachelines anyway?
Confused...
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