lib/smp_processor_id: Make migration check unconditional of SMP

Commit cac5cef ("sched/smp: Make SMP unconditional")
migrate_disable() even on UP builds.
Commit 06ddd17 ("sched/smp: Always define is_percpu_thread() and
scheduler_ipi()") made is_percpu_thread() check the affinity mask
instead replying always true for UP mask.

As a consequence smp_processor_id() now complains if invoked within a
migrate_disable() section because is_percpu_thread() checks its mask and
the migration check is left out.

Make migration check unconditional of SMP.

Fixes: cac5cef ("sched/smp: Make SMP unconditional")
Closes: https://lore.kernel.org/oe-lkp/[email protected]
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Chen Yu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Sebastian Andrzej Siewior

lib/smp_processor_id.c

@@ -22,10 +22,8 @@ unsigned int check_preemption_disabled(const char *what1, const char *what2)
 	if (is_percpu_thread())
 		goto out;
 
-#ifdef CONFIG_SMP
 	if (current->migration_disabled)
 		goto out;
-#endif
 
 	/*
 	 * It is valid to assume CPU-locality during early bootup: