x86/fpu: Use task_disable_lazy_fpu_restore() helper

Replace magic assignments of fpu.last_cpu = ~0 with more explicit
task_disable_lazy_fpu_restore() calls.

Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1423252925-14451-8-git-send-email-riel@redhat.com
Signed-off-by: Borislav Petkov <bp@suse.de>
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 04c2807..e5f8f8e 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -439,7 +439,7 @@
 
 	if (__thread_has_fpu(old)) {
 		if (!__save_init_fpu(old))
-			old->thread.fpu.last_cpu = ~0;
+			task_disable_lazy_fpu_restore(old);
 		else
 			old->thread.fpu.last_cpu = cpu;
 
@@ -455,7 +455,7 @@
 			stts();
 	} else {
 		old->thread.fpu_counter = 0;
-		old->thread.fpu.last_cpu = ~0;
+		task_disable_lazy_fpu_restore(old);
 		if (fpu.preload) {
 			new->thread.fpu_counter++;
 			if (!use_eager_fpu() && fpu_lazy_restore(new, cpu))
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index f3ced6f..5722ab6 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -236,7 +236,7 @@
 	if (tsk_used_math(tsk)) {
 		if (cpu_has_fpu && tsk == current)
 			unlazy_fpu(tsk);
-		tsk->thread.fpu.last_cpu = ~0;
+		task_disable_lazy_fpu_restore(tsk);
 		return 0;
 	}
 
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index e127dda..ce8b103 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -68,8 +68,8 @@
 
 	dst->thread.fpu_counter = 0;
 	dst->thread.fpu.has_fpu = 0;
-	dst->thread.fpu.last_cpu = ~0;
 	dst->thread.fpu.state = NULL;
+	task_disable_lazy_fpu_restore(dst);
 	if (tsk_used_math(src)) {
 		int err = fpu_alloc(&dst->thread.fpu);
 		if (err)