scsi: libsas: Fix disk not being scanned in after being removed

As of commit d8649fc ("scsi: libsas: Do discovery on empty PHY to
update PHY info"), do discovery will send a new SMP_DISCOVER and update
phy->phy_change_count. We found that if the disk is reconnected and phy
change_count changes at this time, the disk scanning process will not be
triggered.

Therefore, call sas_set_ex_phy() to update the PHY info with the results of
the last query. And because the previous phy info will be used when calling
sas_unregister_devs_sas_addr(), sas_unregister_devs_sas_addr() should be
called before sas_set_ex_phy().

Fixes: d8649fc ("scsi: libsas: Do discovery on empty PHY to update PHY info")
Signed-off-by: Xingui Yang <yangxingui@huawei.com>
Link: https://lore.kernel.org/r/20240307141413.48049-3-yangxingui@huawei.com
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: Xingui Yang

drivers/scsi/libsas/sas_expander.c

@@ -1945,6 +1945,7 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
 	struct expander_device *ex = &dev->ex_dev;
 	struct ex_phy *phy = &ex->ex_phy[phy_id];
 	enum sas_device_type type = SAS_PHY_UNUSED;
+	struct smp_disc_resp *disc_resp;
 	u8 sas_addr[SAS_ADDR_SIZE];
 	char msg[80] = "";
 	int res;
@@ -1956,33 +1957,41 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
 		 SAS_ADDR(dev->sas_addr), phy_id, msg);
 
 	memset(sas_addr, 0, SAS_ADDR_SIZE);
-	res = sas_get_phy_attached_dev(dev, phy_id, sas_addr, &type);
+	disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
+	if (!disc_resp)
+		return -ENOMEM;
+
+	res = sas_get_phy_discover(dev, phy_id, disc_resp);
 	switch (res) {
 	case SMP_RESP_NO_PHY:
 		phy->phy_state = PHY_NOT_PRESENT;
 		sas_unregister_devs_sas_addr(dev, phy_id, last);
-		return res;
+		goto out_free_resp;
 	case SMP_RESP_PHY_VACANT:
 		phy->phy_state = PHY_VACANT;
 		sas_unregister_devs_sas_addr(dev, phy_id, last);
-		return res;
+		goto out_free_resp;
 	case SMP_RESP_FUNC_ACC:
 		break;
 	case -ECOMM:
 		break;
 	default:
-		return res;
+		goto out_free_resp;
 	}
 
+	if (res == 0)
+		sas_get_sas_addr_and_dev_type(disc_resp, sas_addr, &type);
+
 	if ((SAS_ADDR(sas_addr) == 0) || (res == -ECOMM)) {
 		phy->phy_state = PHY_EMPTY;
 		sas_unregister_devs_sas_addr(dev, phy_id, last);
 		/*
-		 * Even though the PHY is empty, for convenience we discover
-		 * the PHY to update the PHY info, like negotiated linkrate.
+		 * Even though the PHY is empty, for convenience we update
+		 * the PHY info, like negotiated linkrate.
 		 */
-		sas_ex_phy_discover(dev, phy_id);
-		return res;
+		if (res == 0)
+			sas_set_ex_phy(dev, phy_id, disc_resp);
+		goto out_free_resp;
 	} else if (SAS_ADDR(sas_addr) == SAS_ADDR(phy->attached_sas_addr) &&
 		   dev_type_flutter(type, phy->attached_dev_type)) {
 		struct domain_device *ata_dev = sas_ex_to_ata(dev, phy_id);
@@ -1994,7 +2003,7 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
 			action = ", needs recovery";
 		pr_debug("ex %016llx phy%02d broadcast flutter%s\n",
 			 SAS_ADDR(dev->sas_addr), phy_id, action);
-		return res;
+		goto out_free_resp;
 	}
 
 	/* we always have to delete the old device when we went here */
@@ -2003,7 +2012,10 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
 		SAS_ADDR(phy->attached_sas_addr));
 	sas_unregister_devs_sas_addr(dev, phy_id, last);
 
-	return sas_discover_new(dev, phy_id);
+	res = sas_discover_new(dev, phy_id);
+out_free_resp:
+	kfree(disc_resp);
+	return res;
 }
 
 /**