kmod: remove unecessary explicit wide CPU affinity setting

Khelper is affine to all CPUs.  Now since it creates the
call_usermodehelper_exec_[a]sync() kernel threads, those inherit the wide
affinity.

As such explicitly forcing a wide affinity from those kernel threads
is like a no-op.

Just remove it. It's needless and it breaks CPU isolation users who
rely on workqueue affinity tuning.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Rik van Riel <[email protected]>
Reviewed-by: Oleg Nesterov <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Rusty Russell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

kernel/kmod.c

@@ -224,9 +224,6 @@ static int call_usermodehelper_exec_async(void *data)
 	flush_signal_handlers(current, 1);
 	spin_unlock_irq(&current->sighand->siglock);
 
-	/* We can run anywhere, unlike our parent keventd(). */
-	set_cpus_allowed_ptr(current, cpu_all_mask);
-
 	/*
 	 * Our parent is keventd, which runs with elevated scheduling priority.
 	 * Avoid propagating that into the userspace child.