[SCSI] libsas: fix ata_eh clobbering ex_phys via smp_ata_check_ready

The check_ready implementation in the expander-attached ata device case
polls on sas_ex_phy_discover(). The effect is that the ex_phy fields
(critically ->attached_sas_addr) can change. When ata_eh ends and
libsas comes along to revalidate the domain
sas_unregister_devs_sas_addr() can fail to lookup devices to remove, or
fail to re-add an ata device that ata_eh marked as disabled. So change
the code to skip the sas_address and change count updates when ata_eh is
active.

Cc: Jack Wang <[e-mail]>
Tested-by: Maciej Patelczyk <[e-mail]>
Tested-by: Bartek Nowakowski <[e-mail]>
Tested-by: Jacek Danecki <[e-mail]>
Signed-off-by: Dan Williams <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/libsas/sas_expander.c

···
 	u8 sas_addr[SAS_ADDR_SIZE];
 	struct smp_resp *resp = rsp;
 	struct discover_resp *dr = &resp->disc;
+	struct sas_ha_struct *ha = dev->port->ha;
 	struct expander_device *ex = &dev->ex_dev;
 	struct ex_phy *phy = &ex->ex_phy[phy_id];
 	struct sas_rphy *rphy = dev->rphy;
···
 	char *type;
 
 	if (new_phy) {
+		if (WARN_ON_ONCE(test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state)))
+			return;
 		phy->phy = sas_phy_alloc(&rphy->dev, phy_id);
 
 		/* FIXME: error_handling */
···
 	memcpy(sas_addr, phy->attached_sas_addr, SAS_ADDR_SIZE);
 
 	phy->attached_dev_type = to_dev_type(dr);
+	if (test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state))
+		goto out;
 	phy->phy_id = phy_id;
 	phy->linkrate = dr->linkrate;
 	phy->attached_sata_host = dr->attached_sata_host;
···
 			return;
 		}
 
+ out:
 	switch (phy->attached_dev_type) {
 	case SATA_PENDING:
 		type = "stp pending";
···
 	else
 		return;
 
-	SAS_DPRINTK("ex %016llx phy%02d:%c:%X attached: %016llx (%s)\n",
+	/* if the attached device type changed and ata_eh is active,
+	 * make sure we run revalidation when eh completes (see:
+	 * sas_enable_revalidation)
+	 */
+	if (test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state))
+		set_bit(DISCE_REVALIDATE_DOMAIN, &dev->port->disc.pending);
+
+	SAS_DPRINTK("%sex %016llx phy%02d:%c:%X attached: %016llx (%s)\n",
+		    test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state) ? "ata: " : "",
 		    SAS_ADDR(dev->sas_addr), phy->phy_id,
 		    sas_route_char(dev, phy), phy->linkrate,
 		    SAS_ADDR(phy->attached_sas_addr), type);