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

Migrate this function to pure 'struct fpu' usage.
Reviewed-by: NBorislav 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: NIngo Molnar <mingo@kernel.org>

arch/x86/include/asm/fpu-internal.h

@@ -535,7 +535,7 @@ extern void fpstate_cache_init(void);
 
 extern int fpstate_alloc(struct fpu *fpu);
 extern void fpstate_free(struct fpu *fpu);
-extern int fpu__copy(struct task_struct *dst, struct task_struct *src);
+extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu);
 
 static inline unsigned long
 alloc_mathframe(unsigned long sp, int ia32_frame, unsigned long *buf_fx,

arch/x86/kernel/fpu/core.c

@@ -240,15 +240,12 @@ static void fpu_copy(struct fpu *dst_fpu, struct fpu *src_fpu)
 	}
 }
 
-int fpu__copy(struct task_struct *dst, struct task_struct *src)
+int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
 {
-	struct fpu *dst_fpu = &dst->thread.fpu;
-	struct fpu *src_fpu = &src->thread.fpu;
-
-	dst->thread.fpu.counter = 0;
-	dst->thread.fpu.has_fpu = 0;
-	dst->thread.fpu.state = NULL;
-	dst->thread.fpu.last_cpu = -1;
+	dst_fpu->counter = 0;
+	dst_fpu->has_fpu = 0;
+	dst_fpu->state = NULL;
+	dst_fpu->last_cpu = -1;
 
 	if (src_fpu->fpstate_active) {
 		int err = fpstate_alloc(dst_fpu);

arch/x86/kernel/process.c

@@ -83,7 +83,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
 	*dst = *src;
 
-	return fpu__copy(dst, src);
+	return fpu__copy(&dst->thread.fpu, &src->thread.fpu);
 }
 
 void arch_release_task_struct(struct task_struct *tsk)