um: Remove unused mm_fd field from mm_id

It's no longer used since the removal of the SKAS3/4 support.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/include/shared/skas/mm_id.h

@@ -7,10 +7,7 @@
 #define __MM_ID_H
 
 struct mm_id {
-	union {
-		int mm_fd;
-		int pid;
-	} u;
+	int pid;
 	unsigned long stack;
 	int syscall_data_len;
 };

arch/um/kernel/reboot.c

@@ -29,7 +29,7 @@ static void kill_off_processes(void)
 		t = find_lock_task_mm(p);
 		if (!t)
 			continue;
-		pid = t->mm->context.id.u.pid;
+		pid = t->mm->context.id.pid;
 		task_unlock(t);
 		os_kill_ptraced_process(pid, 1);
 	}

arch/um/kernel/skas/mmu.c

@@ -32,11 +32,11 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
 	new_id->stack = stack;
 
 	block_signals_trace();
-	new_id->u.pid = start_userspace(stack);
+	new_id->pid = start_userspace(stack);
 	unblock_signals_trace();
 
-	if (new_id->u.pid < 0) {
-		ret = new_id->u.pid;
+	if (new_id->pid < 0) {
+		ret = new_id->pid;
 		goto out_free;
 	}
 
@@ -83,12 +83,12 @@ void destroy_context(struct mm_struct *mm)
 	 * whole UML suddenly dying.  Also, cover negative and
 	 * 1 cases, since they shouldn't happen either.
 	 */
-	if (mmu->id.u.pid < 2) {
+	if (mmu->id.pid < 2) {
 		printk(KERN_ERR "corrupt mm_context - pid = %d\n",
-		       mmu->id.u.pid);
+		       mmu->id.pid);
 		return;
 	}
-	os_kill_ptraced_process(mmu->id.u.pid, 1);
+	os_kill_ptraced_process(mmu->id.pid, 1);
 
 	free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES));
 }

arch/um/kernel/time.c

@@ -839,7 +839,7 @@ static irqreturn_t um_timer(int irq, void *dev)
 	if (get_current()->mm != NULL)
 	{
         /* userspace - relay signal, results in correct userspace timers */
-		os_alarm_process(get_current()->mm->context.id.u.pid);
+		os_alarm_process(get_current()->mm->context.id.pid);
 	}
 
 	(*timer_clockevent.event_handler)(&timer_clockevent);

arch/um/os-Linux/skas/mem.c

@@ -78,7 +78,7 @@ static inline long do_syscall_stub(struct mm_id *mm_idp)
 {
 	struct stub_data *proc_data = (void *)mm_idp->stack;
 	int n, i;
-	int err, pid = mm_idp->u.pid;
+	int err, pid = mm_idp->pid;
 
 	n = ptrace_setregs(pid, syscall_regs);
 	if (n < 0) {

arch/um/os-Linux/skas/process.c

@@ -588,5 +588,5 @@ void reboot_skas(void)
 
 void __switch_mm(struct mm_id *mm_idp)
 {
-	userspace_pid[0] = mm_idp->u.pid;
+	userspace_pid[0] = mm_idp->pid;
 }