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 909d10d2fb70e355485be45fc4ac448070dc52c5..76006a701dbbab1c50d39f931fcbdf655034fe26 100644 (file)
--- 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;
        }