[PATCH RFC 4/6] ata: libata-scsi: Add ata_scsi_setup_sdev()

[John Garry <john.garry@huawei.com>]

Add a function to setup the sdev associated with an ata_device.

Currently in libata to create the sdev we call __scsi_add_device() to
create the sdev and execute the scan. However if we want to move to a
2-step process where we allocate the sdev early in the port probe, then
we need a separate function just to allocate the sdev.

We add a ata_port_operations callback .setup_scsi_device for when the
driver needs a custom setup. This is essentially for libsas, which does
not use the same options for sdev parent and id.

Signed-off-by: John Garry <john.garry@huawei.com>
---
 drivers/ata/libata-scsi.c | 25 +++++++++++++++++++++++++
 drivers/ata/libata.h      |  1 +
 include/linux/libata.h    |  2 ++
 3 files changed, 28 insertions(+)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 29e2f55c6faa..88f39ab10a92 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -4257,6 +4257,31 @@ static void ata_scsi_assign_ofnode(struct ata_device *dev, struct ata_port *ap)
 }
 #endif
 
+int ata_scsi_setup_sdev(struct ata_device *dev)
+{
+	u64 lun = 0;
+	int channel = 0;
+	uint id = 0;
+	struct ata_link *link = dev->link;
+	struct ata_port *ap = link->ap;
+	struct Scsi_Host *shost = ap->scsi_host;
+	struct device *parent = &shost->shost_gendev;
+	struct scsi_device *sdev;
+
+	if (ap->ops->setup_scsi_device)
+		return ap->ops->setup_scsi_device(dev);
+
+	if (ata_is_host_link(link))
+		id = dev->devno;
+	else
+		channel = link->pmp;
+	sdev = scsi_get_dev(parent, channel, id, lun);
+	if (!sdev)
+		return -ENODEV;
+	dev->sdev = sdev;
+	return 0;
+}
+
 void ata_scsi_scan_host(struct ata_port *ap, int sync)
 {
 	int tries = 5;
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 98bc8649c63f..ca6c3e0f81ea 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -113,6 +113,7 @@ extern struct ata_device *ata_scsi_find_dev(struct ata_port *ap,
 					    const struct scsi_device *scsidev);
 extern int ata_scsi_add_hosts(struct ata_host *host,
 			      struct scsi_host_template *sht);
+extern int ata_scsi_setup_sdev(struct ata_device *dev);
 extern void ata_scsi_scan_host(struct ata_port *ap, int sync);
 extern int ata_scsi_offline_dev(struct ata_device *dev);
 extern void ata_scsi_set_sense(struct ata_device *dev,
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 698032e5ef2d..67aa1d7d909b 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -968,6 +968,8 @@ struct ata_port_operations {
 	void (*phy_reset)(struct ata_port *ap);
 	void (*eng_timeout)(struct ata_port *ap);
 
+	int (*setup_scsi_device)(struct ata_device *dev);
+
 	/*
 	 * ->inherits must be the last field and all the preceding
 	 * fields must be pointers.
-- 
2.35.3