[SCSI] zfcp: Track fabric and channel latencies provided by FCP adapter

Add the infrastructure to retrieve the fabric and channel latencies
from FSF commands for each SCSI command that has been processed. For
each unit, the sum, min, max and number of requests is tracked.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 8c7e2b778ef1..d23027a2f2f0 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -847,6 +847,14 @@ zfcp_unit_enqueue(struct zfcp_port *port, fcp_lun_t fcp_lun)
         /* mark unit unusable as long as sysfs registration is not complete */
         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
 
+        spin_lock_init(&unit->latencies.lock);
+        unit->latencies.write.channel.min = 0xFFFFFFFF;
+        unit->latencies.write.fabric.min = 0xFFFFFFFF;
+        unit->latencies.read.channel.min = 0xFFFFFFFF;
+        unit->latencies.read.fabric.min = 0xFFFFFFFF;
+        unit->latencies.cmd.channel.min = 0xFFFFFFFF;
+        unit->latencies.cmd.fabric.min = 0xFFFFFFFF;
+
         if (device_register(&unit->sysfs_device)) {
                 kfree(unit);
                 return NULL;