x86/fpu: Simplify and speed up fpu__copy()
authorIngo Molnar <mingo@kernel.org>
Sat, 23 Sep 2017 13:00:14 +0000 (15:00 +0200)
committerIngo Molnar <mingo@kernel.org>
Tue, 26 Sep 2017 07:43:44 +0000 (09:43 +0200)
commite10078eba69859359ce8644dd423b4132a6a8913
treedb0aadc1cbc41c2690877954ed396dcdec85a860
parent7f1487c59b7c6dcb20155f4302985da2659a2997
x86/fpu: Simplify and speed up fpu__copy()

fpu__copy() has a preempt_disable()/enable() pair, which it had to do to
be able to atomically unlazy the current task when doing an FNSAVE.

But we don't unlazy tasks anymore, we always do direct saves/restores of
FPU context.

So remove both the unnecessary critical section, and update the comments.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-32-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/kernel/fpu/core.c