scsi: libsas: Introduce sas_find_attached_phy_id() helper

LLDDs are all implementing their own attached phy ID finding code.  Factor
it out to libsas.
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20220928070130.3657183-3-yanaijie@huawei.comReviewed-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/libsas/sas_expander.c

@@ -2107,6 +2107,22 @@ int sas_ex_revalidate_domain(struct domain_device *port_dev)
 	return res;
 }
 
+int sas_find_attached_phy_id(struct expander_device *ex_dev,
+			     struct domain_device *dev)
+{
+	struct ex_phy *phy;
+	int phy_id;
+
+	for (phy_id = 0; phy_id < ex_dev->num_phys; phy_id++) {
+		phy = &ex_dev->ex_phy[phy_id];
+		if (sas_phy_match_dev_addr(dev, phy))
+			return phy_id;
+	}
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(sas_find_attached_phy_id);
+
 void sas_smp_handler(struct bsg_job *job, struct Scsi_Host *shost,
 		struct sas_rphy *rphy)
 {

include/scsi/libsas.h

@@ -746,6 +746,8 @@ int sas_clear_task_set(struct domain_device *dev, u8 *lun);
 int sas_lu_reset(struct domain_device *dev, u8 *lun);
 int sas_query_task(struct sas_task *task, u16 tag);
 int sas_abort_task(struct sas_task *task, u16 tag);
+int sas_find_attached_phy_id(struct expander_device *ex_dev,
+			     struct domain_device *dev);
 
 void sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event,
 			   gfp_t gfp_flags);