Re: [RFC] nvfs: a filesystem for persistent memory

From: Mikulas Patocka
Date: Tue Sep 15 2020 - 14:39:51 EST




On Tue, 15 Sep 2020, Mikulas Patocka wrote:

> > > - __copy_from_user_inatomic_nocache doesn't flush cache for leading and
> > > trailing bytes.
> >
> > You want copy_user_flushcache(). See how fs/dax.c arranges for
> > dax_copy_from_iter() to route to pmem_copy_from_iter().
>
> Is it something new for the kernel 5.10? I see only __copy_user_flushcache
> that is implemented just for x86 and arm64.
>
> There is __copy_from_user_flushcache implemented for x86, arm64 and power.
> It is used in lib/iov_iter.c under
> #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE - so should I use this?
>
> Mikulas

... and __copy_user_flushcache is not exported for modules. So, I am stuck
with __copy_from_user_inatomic_nocache.

Mikulas