[PATCH AUTOSEL 4.14 38/46] scsi: ibmvfc: Avoid unnecessary port relogin

From: Sasha Levin
Date: Thu Oct 25 2018 - 10:12:42 EST

From: Brian King <brking@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 09dd15e0d9547ca424de4043bcd429bab6f285c8 ]

Following an RSCN, ibmvfc will issue an ADISC to determine if the
underlying target has changed, comparing the SCSI ID, WWPN, and WWNN to
determine how to handle the rport in discovery. However, the comparison
of the WWPN and WWNN was performing a memcmp between a big endian field
against a CPU endian field, which resulted in the wrong answer on LE
systems. This was observed as unexpected errors getting logged at boot
time as targets were getting relogins when not needed.

Signed-off-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/scsi/ibmvscsi/ibmvfc.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index b491af31a5f8..a06b24a61622 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -3580,11 +3580,9 @@ static void ibmvfc_tgt_implicit_logout(struct ibmvfc_target *tgt)
static int ibmvfc_adisc_needs_plogi(struct ibmvfc_passthru_mad *mad,
struct ibmvfc_target *tgt)
- if (memcmp(&mad->fc_iu.response[2], &tgt->ids.port_name,
- sizeof(tgt->ids.port_name)))
+ if (wwn_to_u64((u8 *)&mad->fc_iu.response[2]) != tgt->ids.port_name)
return 1;
- if (memcmp(&mad->fc_iu.response[4], &tgt->ids.node_name,
- sizeof(tgt->ids.node_name)))
+ if (wwn_to_u64((u8 *)&mad->fc_iu.response[4]) != tgt->ids.node_name)
return 1;
if (be32_to_cpu(mad->fc_iu.response[6]) != tgt->scsi_id)
return 1;