[PATCH 4/6] lpfc: Initialize cpu_map for not present cpus

[James Smart <jsmart2021@gmail.com>]

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 cpu's.

Fixes: dcaa21367938 ("scsi: lpfc: Change default IRQ model on AMD architectures")
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
---
Issue applies as of the 12.2.0.0 patch kit, but this fix requires
the above patch set for resolution. Referenced patch is in the
5.5/scsi-queue branch
---
 drivers/scsi/lpfc/lpfc_init.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 480d5a28c4f5..2b0e1097f727 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/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.
 	 */
-- 
2.13.7