padata: Remove cpu online check from cpu add and removal

[ Upstream commit 73117ea ]

During the CPU offline process, the dying CPU is cleared from the
cpu_online_mask in takedown_cpu(). After this step, various CPUHP_*_DEAD
callbacks are executed to perform cleanup jobs for the dead CPU, so this
cpu online check in padata_cpu_dead() is unnecessary.

Similarly, when executing padata_cpu_online() during the
CPUHP_AP_ONLINE_DYN phase, the CPU has already been set in the
cpu_online_mask, the action even occurs earlier than the
CPUHP_AP_ONLINE_IDLE stage.

Remove this unnecessary cpu online check in __padata_add_cpu() and
__padata_remove_cpu().

Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Stable-dep-of: c8c4a29 ("padata: Put CPU offline callback in ONLINE section to allow failure")
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: kchuyizhou

kernel/padata.c

@@ -736,32 +736,22 @@ EXPORT_SYMBOL(padata_set_cpumask);
 
 static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
 {
-	int err = 0;
-
-	if (cpumask_test_cpu(cpu, cpu_online_mask)) {
-		err = padata_replace(pinst);
+	int err = padata_replace(pinst);
 
-		if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
-		    padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
-			__padata_start(pinst);
-	}
+	if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
+	    padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
+		__padata_start(pinst);
 
 	return err;
 }
 
 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
 {
-	int err = 0;
-
-	if (!cpumask_test_cpu(cpu, cpu_online_mask)) {
-		if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
-		    !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
-			__padata_stop(pinst);
-
-		err = padata_replace(pinst);
-	}
+	if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
+	    !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
+		__padata_stop(pinst);
 
-	return err;
+	return padata_replace(pinst);
 }
 
 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)