[PATCH 4/4] scsi: hisi_sas: Disable SATA disk phy for severe I_T nexus reset failure

[John Garry]

From: Luo Jiaxing <luojiaxing@xxxxxxxxxx>

If the softreset fails in the I_T reset, libsas will then continue to
issue a controller reset to try to recover.

However a faulty disk may cause the softreset to fail, and resetting the
controller will not help this scenario. Indeed, we will just continue the
cycle of error handle handling to try to recover.

So if the softreset fails upon certain conditions, just disable the phy
associated with the disk. The user needs to handle this problem.

Signed-off-by: Luo Jiaxing <luojiaxing@xxxxxxxxxx>
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
 drivers/scsi/hisi_sas/hisi_sas_main.c | 29 ++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 5b091388c095..f206c433de32 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -1870,14 +1870,33 @@ static int hisi_sas_I_T_nexus_reset(struct domain_device *device)
 	}
 	hisi_sas_dereg_device(hisi_hba, device);
 
-	if (dev_is_sata(device)) {
+	rc = hisi_sas_debug_I_T_nexus_reset(device);
+	if (rc == TMF_RESP_FUNC_COMPLETE && dev_is_sata(device)) {
+		struct sas_phy *local_phy;
+
 		rc = hisi_sas_softreset_ata_disk(device);
-		if (rc == TMF_RESP_FUNC_FAILED)
-			return TMF_RESP_FUNC_FAILED;
+		switch (rc) {
+		case -ECOMM:
+			rc = -ENODEV;
+			break;
+		case TMF_RESP_FUNC_FAILED:
+		case -EMSGSIZE:
+		case -EIO:
+			local_phy = sas_get_local_phy(device);
+			rc = sas_phy_enable(local_phy, 0);
+			if (!rc) {
+				local_phy->enabled = 0;
+				dev_err(dev, "Disabled local phy of ATA disk %016llx due to softreset fail (%d)\n",
+					SAS_ADDR(device->sas_addr), rc);
+				rc = -ENODEV;
+			}
+			sas_put_local_phy(local_phy);
+			break;
+		default:
+			break;
+		}
 	}
 
-	rc = hisi_sas_debug_I_T_nexus_reset(device);
-
 	if ((rc == TMF_RESP_FUNC_COMPLETE) || (rc == -ENODEV))
 		hisi_sas_release_task(hisi_hba, device);
 
-- 
2.26.2