scsi: lpfc: Initialize cpu_map for not present cpus

Currently, cpu_map[cpu#]->hdwq is left to equal LPFC_VECTOR_MAP_EMPTY for
not present CPUs.  If a CPU is dynamically hot-added, it is possible we may
crash due to not assigning an allocated hdwq.

Correct by assigning a hdwq at initialization for all not-present CPUs.

Fixes: dcaa2136 ("scsi: lpfc: Change default IRQ model on AMD architectures")
Link: https://lore.kernel.org/r/20191111230401.12958-5-jsmart2021@gmail.comReviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_init.c

@@ -11004,7 +11004,7 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 				cpu, cpup->phys_id, cpup->core_id,
 				cpup->hdwq, cpup->eq, cpup->flag);
 	}
-	/* Finally we need to associate a hdwq with each cpu_map entry
+	/* Associate a hdwq with each cpu_map entry
 	 * This will be 1 to 1 - hdwq to cpu, unless there are less
 	 * hardware queues then CPUs. For that case we will just round-robin
 	 * the available hardware queues as they get assigned to CPUs.
@@ -11083,6 +11083,23 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 				cpup->hdwq, cpup->eq, cpup->flag);
 	}
 
+	/*
+	 * Initialize the cpu_map slots for not-present cpus in case
+	 * a cpu is hot-added. Perform a simple hdwq round robin assignment.
+	 */
+	idx = 0;
+	for_each_possible_cpu(cpu) {
+		cpup = &phba->sli4_hba.cpu_map[cpu];
+		if (cpup->hdwq != LPFC_VECTOR_MAP_EMPTY)
+			continue;
+
+		cpup->hdwq = idx++ % phba->cfg_hdw_queue;
+		lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
+				"3340 Set Affinity: not present "
+				"CPU %d hdwq %d\n",
+				cpu, cpup->hdwq);
+	}
+
 	/* The cpu_map array will be used later during initialization
 	 * when EQ / CQ / WQs are allocated and configured.
 	 */