[PATCH AUTOSEL for 4.9 196/219] scsi: ses: don't ask for diagnostic pages repeatedly during probe

Sasha Levin
2018-03-03T23:25:57Z

From: Li Dongyang <dongyang.li@anu.edu.au>

[ Upstream commit 9c0a50022b8ac7e863e6ec8342fa476fe5d1d75c ]

We are testing if there is a match with the ses device in a loop by
calling ses_match_to_enclosure(), which will issue scsi receive
diagnostics commands to the ses device for every device on the same
host. On one of our boxes with 840 disks, it takes a long time to load
the driver:

[root@g1b-oss06 ~]# time modprobe ses

real 40m48.247s
user 0m0.001s
sys 0m0.196s

With the patch:

[root@g1b-oss06 ~]# time modprobe ses

real 0m17.915s
user 0m0.008s
sys 0m0.053s

Note that we still need to refresh page 10 when we see a new disk to
create the link.

Signed-off-by: Li Dongyang <dongyang.li@anu.edu.au>
Tested-by: Jason Ozolins <jason.ozolins@hpe.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/scsi/ses.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index f1cdf32d7514..69046d342bc5 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -578,13 +578,16 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
}

static void ses_match_to_enclosure(struct enclosure_device *edev,
- struct scsi_device *sdev)
+ struct scsi_device *sdev,
+ int refresh)
{
+ struct scsi_device *edev_sdev = to_scsi_device(edev->edev.parent);
struct efd efd = {
.addr = 0,
};

- ses_enclosure_data_process(edev, to_scsi_device(edev->edev.parent), 0);
+ if (refresh)
+ ses_enclosure_data_process(edev, edev_sdev, 0);

if (scsi_is_sas_rphy(sdev->sdev_target->dev.parent))
efd.addr = sas_get_address(sdev);
@@ -615,7 +618,7 @@ static int ses_intf_add(struct device *cdev,
struct enclosure_device *prev = NULL;

while ((edev = enclosure_find(&sdev->host->shost_gendev, prev)) != NULL) {
- ses_match_to_enclosure(edev, sdev);
+ ses_match_to_enclosure(edev, sdev, 1);
prev = edev;
}
return -ENODEV;
@@ -727,7 +730,7 @@ static int ses_intf_add(struct device *cdev,
shost_for_each_device(tmp_sdev, sdev->host) {
if (tmp_sdev->lun != 0 || scsi_device_enclosure(tmp_sdev))
continue;
- ses_match_to_enclosure(edev, tmp_sdev);
+ ses_match_to_enclosure(edev, tmp_sdev, 0);
}

return 0;
--
2.14.1