mm/slub: Refactor note_cmpxchg_failure for better readability

Use IS_ENABLED() and standard if-else to make the code clearer.

Signed-off-by: Ye Liu <[email protected]>
Reviewed-by: Harry Yoo <[email protected]>
Reviewed-by: Christoph Lameter (Ampere) <[email protected]>
Reviewed-by: Anshuman Khandual <[email protected]>
Signed-off-by: Vlastimil Babka <[email protected]>

Author: qiyeliu

mm/slub.c

@@ -3069,18 +3069,17 @@ static inline void note_cmpxchg_failure(const char *n,
 
 	pr_info("%s %s: cmpxchg redo ", n, s->name);
 
-#ifdef CONFIG_PREEMPTION
-	if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
+	if (IS_ENABLED(CONFIG_PREEMPTION) &&
+	    tid_to_cpu(tid) != tid_to_cpu(actual_tid)) {
 		pr_warn("due to cpu change %d -> %d\n",
 			tid_to_cpu(tid), tid_to_cpu(actual_tid));
-	else
-#endif
-	if (tid_to_event(tid) != tid_to_event(actual_tid))
+	} else if (tid_to_event(tid) != tid_to_event(actual_tid)) {
 		pr_warn("due to cpu running other code. Event %ld->%ld\n",
 			tid_to_event(tid), tid_to_event(actual_tid));
-	else
+	} else {
 		pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
 			actual_tid, tid, next_tid(tid));
+	}
 #endif
 	stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
 }