From: Ingo Molnar <mingo@kernel.org>
Date: Fri, 3 Apr 2015 10:28:15 +0000 (+0200)
Subject: x86/fpu: Optimize fpu__unlazy_stopped()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8694c3e793810de3f7ff612d0fc23b70dc5a7e4d;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

x86/fpu: Optimize fpu__unlazy_stopped()

This function is only called for stopped child tasks, so the
fpu__save() branch will never get called - remove it.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 909d10d2fb70..76006a701dbb 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -291,8 +291,6 @@ static int fpu__unlazy_stopped(struct task_struct *child)
 		return -EINVAL;
 
 	if (tsk_used_math(child)) {
-		if (cpu_has_fpu && child == current)
-			fpu__save(child);
 		task_disable_lazy_fpu_restore(child);
 		return 0;
 	}