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

James Smart
2019-11-11T23:04:20Z

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