mips: copy_thread(): rename 'arg' argument to 'kthread_arg'

The 'arg' argument to copy_thread() is only ever used when forking a new
kernel thread. Hence, rename it to 'kthread_arg' for clarity (and consistency
with do_fork() and other arch-specific implementations of copy_thread()).

Signed-off-by: Alex Dowad <alexinbeijing@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Eunbong Song <eunb.song@samsung.com>
Cc: linux-mips@linux-mips.org (open list:MIPS)
Patchwork: https://patchwork.linux-mips.org/patch/9546/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/process.c

@@ -107,8 +107,11 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 	return 0;
 }
 
+/*
+ * Copy architecture-specific thread state
+ */
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-	unsigned long arg, struct task_struct *p)
+	unsigned long kthread_arg, struct task_struct *p)
 {
 	struct thread_info *ti = task_thread_info(p);
 	struct pt_regs *childregs, *regs = current_pt_regs();
@@ -123,11 +126,12 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 	childksp = (unsigned long) childregs;
 	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
 	if (unlikely(p->flags & PF_KTHREAD)) {
+		/* kernel thread */
 		unsigned long status = p->thread.cp0_status;
 		memset(childregs, 0, sizeof(struct pt_regs));
 		ti->addr_limit = KERNEL_DS;
 		p->thread.reg16 = usp; /* fn */
-		p->thread.reg17 = arg;
+		p->thread.reg17 = kthread_arg;
 		p->thread.reg29 = childksp;
 		p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
@@ -139,6 +143,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 		childregs->cp0_status = status;
 		return 0;
 	}
+
+	/* user thread */
 	*childregs = *regs;
 	childregs->regs[7] = 0; /* Clear error flag */
 	childregs->regs[2] = 0; /* Child gets zero as return value */