From 6cf4edbe0526db311a28734609da888fdfcb3604 Mon Sep 17 00:00:00 2001
From: Ingo Molnar
Date: Sat, 23 Sep 2017 15:00:02 +0200
Subject: x86/fpu: Decouple fpregs_activate()/fpregs_deactivate() from
 fpu->fpregs_active

The fpregs_activate()/fpregs_deactivate() are currently called in such a pattern:

	if (!fpu->fpregs_active)
		fpregs_activate(fpu);

	...

	if (fpu->fpregs_active)
		fpregs_deactivate(fpu);

But note that it's actually safe to call them without checking the flag first.

This further decouples the fpu->fpregs_active flag from actual FPU logic.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
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/20170923130016.21448-20-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/fpu/core.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'arch/x86/kernel/fpu')

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index eab244622402..01a47e9edfb4 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -426,8 +426,7 @@ void fpu__drop(struct fpu *fpu)
 			asm volatile("1: fwait\n"
 				     "2:\n"
 				     _ASM_EXTABLE(1b, 2b));
-			if (fpu->fpregs_active)
-				fpregs_deactivate(fpu);
+			fpregs_deactivate(fpu);
 		}
 	} else {
 		WARN_ON_FPU(fpu->fpregs_active);
-- 
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