x86/fpu: Use 'struct fpu' in restore_fpu_checking()

Migrate this function to pure 'struct fpu' usage.

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/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 3f6d36c..2d7934e4 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -294,7 +294,7 @@
 		return frstor_checking(&fpu->state->fsave);
 }
 
-static inline int restore_fpu_checking(struct task_struct *tsk)
+static inline int restore_fpu_checking(struct fpu *fpu)
 {
 	/*
 	 * AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception is
@@ -306,10 +306,10 @@
 			"fnclex\n\t"
 			"emms\n\t"
 			"fildl %P[addr]"	/* set F?P to defined value */
-			: : [addr] "m" (tsk->thread.fpu.has_fpu));
+			: : [addr] "m" (fpu->has_fpu));
 	}
 
-	return fpu_restore_checking(&tsk->thread.fpu);
+	return fpu_restore_checking(fpu);
 }
 
 /* Must be paired with an 'stts' after! */
@@ -456,8 +456,10 @@
  */
 static inline void switch_fpu_finish(struct task_struct *new, fpu_switch_t fpu)
 {
+	struct fpu *new_fpu = &new->thread.fpu;
+
 	if (fpu.preload) {
-		if (unlikely(restore_fpu_checking(new)))
+		if (unlikely(restore_fpu_checking(new_fpu)))
 			fpu_reset_state(new);
 	}
 }