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To: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
From: Christophe LEROY <christophe.leroy@c-s.fr>
Subject: usercopy in PPC64
Message-ID: <d25be832-2030-4bc8-dbc5-4baebb759279@c-s.fr>
Date: Tue, 30 May 2017 14:36:39 +0200
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Hi all powerpc64 experts,

While looking at the usercopy efficiency for PPC32, I noticed something 
which looks strange.

In asm/uaccess.h, raw_copy_from_user() and raw_copy_to_user() implements 
a fast path using get_user() and put_user() for copies of constant size < 8.

But INLINE_COPY_FROM_USER and INLINE_COPY_TO_USER are only defined for 
PPC32, so PPC64 will call __copy_tofrom_user() even for small constant 
size copies. Is that wanted ?

Regards
Christophe