um: fix unused variable warning

The code was updated to access the PID of the userspace stub process in
a different way, making the local cpu variable obsolete. Remove it.

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Fixes: 406d17c ("um: Implement kernel side of SECCOMP based process handling")
Signed-off-by: Benjamin Berg <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Johannes Berg <[email protected]>

Author: benzea

arch/x86/um/tls_32.c

@@ -25,7 +25,6 @@ int host_gdt_entry_tls_min;
 static int do_set_thread_area(struct task_struct* task, struct user_desc *info)
 {
 	int ret;
-	u32 cpu;
 
 	if (info->entry_number < host_gdt_entry_tls_min ||
 	    info->entry_number >= host_gdt_entry_tls_min + GDT_ENTRY_TLS_ENTRIES)
@@ -41,9 +40,7 @@ static int do_set_thread_area(struct task_struct* task, struct user_desc *info)
 		return 0;
 	}
 
-	cpu = get_cpu();
 	ret = os_set_thread_area(info, task->mm->context.id.pid);
-	put_cpu();
 
 	if (ret)
 		printk(KERN_ERR "PTRACE_SET_THREAD_AREA failed, err = %d, "