[PATCH v7 4/5] scsi_transport_fc: Added store fucntionality to set the rport port_state using sysfs

[Muneendra <muneendra.kumar@broadcom.com>]

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Added a store functionality to set rport port_state using sysfs
under  fc_remote_ports/rport-*/port_state

With this functionality the user can move the port_state from
Marginal -> Online and Online->Marginal.

On Marginal :This interface will set SCMD_NORETRIES_ABORT bit in
scmd->state for all the pending io's on the scsi device associated
with target port.

On Online :This interface will clear SCMD_NORETRIES_ABORT bit in
scmd->state for all the pending io's on the scsi device associated
with target port.

Below is the interface provided to set the port state to Marginal
and Online.

echo "Marginal" >> /sys/class/fc_remote_ports/rport-X\:Y-Z/port_state
echo "Online" >> /sys/class/fc_remote_ports/rport-X\:Y-Z/port_state

Signed-off-by: Muneendra <muneendra.kumar@broadcom.com>

---
v7:
No change

v6:
No change

v5:
No change

v4:
Addressed the error reported by kernel test robot
Removed the code needed to traverse all the devices under rport
to set/clear SCMD_NORETRIES_ABORT
Removed unncessary comments.
Return the error values on failure while setting the port_state

v3:
Removed the port_state from starget attributes.
Enabled the store functionality for port_state under remote port.
used the starget_for_each_device to traverse around all the devices
under rport

v2:
Changed from a noretries_abort attribute under fc_transport/target*/ to
port_state for changing the port_state to a marginal state
---
 drivers/scsi/scsi_transport_fc.c | 56 ++++++++++++++++++++++++++++++--
 1 file changed, 54 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index ffd25195ae62..d378ca4a60fe 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -1238,7 +1238,59 @@ show_fc_rport_roles (struct device *dev, struct device_attribute *attr,
 static FC_DEVICE_ATTR(rport, roles, S_IRUGO,
 		show_fc_rport_roles, NULL);
 
-fc_private_rport_rd_enum_attr(port_state, FC_PORTSTATE_MAX_NAMELEN);
+static ssize_t fc_rport_set_marginal_state(struct device *dev,
+						struct device_attribute *attr,
+						const char *buf, size_t count)
+{
+	struct fc_rport *rport = transport_class_to_rport(dev);
+	enum fc_port_state port_state;
+	int ret = 0;
+
+	ret = get_fc_port_state_match(buf, &port_state);
+	if (ret)
+		return -EINVAL;
+	if (port_state == FC_PORTSTATE_MARGINAL) {
+		/*
+		 * Change the state to marginal only if the
+		 * current rport state is Online
+		 * Allow only Online->marginal
+		 */
+		if (rport->port_state == FC_PORTSTATE_ONLINE)
+			rport->port_state = port_state;
+		else
+			return -EINVAL;
+	} else if (port_state == FC_PORTSTATE_ONLINE) {
+		/*
+		 * Change the state to Online only if the
+		 * current rport state is Marginal
+		 * Allow only  MArginal->Online
+		 */
+		if (rport->port_state == FC_PORTSTATE_MARGINAL)
+			rport->port_state = port_state;
+		else
+			return -EINVAL;
+	} else
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t
+show_fc_rport_port_state(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	const char *name;
+	struct fc_rport *rport = transport_class_to_rport(dev);
+
+	name = get_fc_port_state_name(rport->port_state);
+	if (!name)
+		return -EINVAL;
+
+	return snprintf(buf, 20, "%s\n", name);
+}
+
+static FC_DEVICE_ATTR(rport, port_state, 0444 | 0200,
+			show_fc_rport_port_state, fc_rport_set_marginal_state);
+
 fc_private_rport_rd_attr(scsi_target_id, "%d\n", 20);
 
 /*
@@ -2681,7 +2733,7 @@ fc_attach_transport(struct fc_function_template *ft)
 	SETUP_PRIVATE_RPORT_ATTRIBUTE_RD(port_name);
 	SETUP_PRIVATE_RPORT_ATTRIBUTE_RD(port_id);
 	SETUP_PRIVATE_RPORT_ATTRIBUTE_RD(roles);
-	SETUP_PRIVATE_RPORT_ATTRIBUTE_RD(port_state);
+	SETUP_PRIVATE_RPORT_ATTRIBUTE_RW(port_state);
 	SETUP_PRIVATE_RPORT_ATTRIBUTE_RD(scsi_target_id);
 	SETUP_PRIVATE_RPORT_ATTRIBUTE_RW(fast_io_fail_tmo);
 
-- 
2.26.2


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