Make it possible to forcibly close SRP and FC sessions via sysfs

That patch contains the following changes:
* Move the code for creating a "close_sess" sysfs attribute from iscsi-scst to
  the SCST core such that it becomes available for other target drivers. This
  does not change the functionality of iscsi-scst.
* Add code in ib_srpt and qla2x00t to allow a session to be forcibly closed from
  user space.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>




git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@4852 d57e44dd-8a1f-0410-8b47-8ef2f437770f

iscsi-scst/kernel/iscsi.c

@@ -3822,6 +3822,24 @@ out_err:
 	return;
 }
 
+static int iscsi_close_sess(struct scst_session *scst_sess)
+{
+	struct iscsi_session *sess = scst_sess_get_tgt_priv(scst_sess);
+	struct iscsi_target *target = sess->target;
+	int res;
+
+	res = mutex_lock_interruptible(&target->target_mutex);
+	if (res)
+		goto out;
+	iscsi_sess_force_close(sess);
+	mutex_unlock(&target->target_mutex);
+
+	res = 0;
+
+out:
+	return res;
+}
+
 static int iscsi_target_detect(struct scst_tgt_template *templ)
 {
 	/* Nothing to do */
@@ -3869,6 +3887,7 @@ struct scst_tgt_template iscsi_template = {
 	.add_target = iscsi_sysfs_add_target,
 	.del_target = iscsi_sysfs_del_target,
 	.mgmt_cmd = iscsi_sysfs_mgmt_cmd,
+	.close_session = iscsi_close_sess,
 	.tgtt_optional_attributes = "IncomingUser, OutgoingUser",
 	.tgt_optional_attributes = "IncomingUser, OutgoingUser, allowed_portal",
 #endif

iscsi-scst/kernel/session.c

@@ -540,36 +540,6 @@ static ssize_t iscsi_sess_reinstating_show(struct kobject *kobj,
 static struct kobj_attribute iscsi_sess_attr_reinstating =
 	__ATTR(reinstating, S_IRUGO, iscsi_sess_reinstating_show, NULL);
 
-static ssize_t iscsi_sess_force_close_store(struct kobject *kobj,
-	struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	int res;
-	struct scst_session *scst_sess;
-	struct iscsi_session *sess;
-
-	TRACE_ENTRY();
-
-	scst_sess = container_of(kobj, struct scst_session, sess_kobj);
-	sess = (struct iscsi_session *)scst_sess_get_tgt_priv(scst_sess);
-
-	res = mutex_lock_interruptible(&sess->target->target_mutex);
-	if (res != 0)
-		goto out;
-
-	iscsi_sess_force_close(sess);
-
-	mutex_unlock(&sess->target->target_mutex);
-
-	res = count;
-
-out:
-	TRACE_EXIT_RES(res);
-	return res;
-}
-
-static struct kobj_attribute iscsi_sess_attr_force_close =
-	__ATTR(force_close, S_IWUSR, NULL, iscsi_sess_force_close_store);
-
 const struct attribute *iscsi_sess_attrs[] = {
 	&iscsi_sess_attr_initial_r2t.attr,
 	&iscsi_sess_attr_immediate_data.attr,
@@ -582,7 +552,6 @@ const struct attribute *iscsi_sess_attrs[] = {
 	&iscsi_sess_attr_data_digest.attr,
 	&iscsi_attr_sess_sid.attr,
 	&iscsi_sess_attr_reinstating.attr,
-	&iscsi_sess_attr_force_close.attr,
 	NULL,
 };
 

qla2x00t/qla2x00-target/qla2x00t.c

@@ -102,6 +102,7 @@ static int q2t_cut_cmd_data_head(struct q2t_cmd *cmd, unsigned int offset);
 static void q2t_clear_tgt_db(struct q2t_tgt *tgt, bool local_only);
 static void q2t_on_hw_pending_cmd_timeout(struct scst_cmd *scst_cmd);
 static int q2t_unreg_sess(struct q2t_sess *sess);
+static int q2t_close_session(struct scst_session *scst_sess);
 static uint16_t q2t_get_scsi_transport_version(struct scst_tgt *scst_tgt);
 static uint16_t q2t_get_phys_transport_version(struct scst_tgt *scst_tgt);
 
@@ -219,6 +220,7 @@ static struct scst_tgt_template tgt2x_template = {
 	.rdy_to_xfer = q2t_rdy_to_xfer,
 	.on_free_cmd = q2t_on_free_cmd,
 	.task_mgmt_fn_done = q2t_task_mgmt_fn_done,
+	.close_session = q2t_close_session,
 	.get_initiator_port_transport_id = q2t_get_initiator_port_transport_id,
 	.get_scsi_transport_version = q2t_get_scsi_transport_version,
 	.get_phys_transport_version = q2t_get_phys_transport_version,
@@ -796,6 +798,20 @@ out:
 	return;
 }
 
+static int q2t_close_session(struct scst_session *scst_sess)
+{
+	struct q2t_sess *sess = scst_sess_get_tgt_priv(scst_sess);
+	scsi_qla_host_t *ha = sess->tgt->ha;
+	scsi_qla_host_t *pha = to_qla_parent(ha);
+	unsigned long flags;
+
+	spin_lock_irqsave(&pha->hardware_lock, flags);
+	q2t_schedule_sess_for_deletion(sess);
+	spin_unlock_irqrestore(&pha->hardware_lock, flags);
+
+	return 0;
+}
+
 /* pha->hardware_lock supposed to be held on entry */
 static void q2t_clear_tgt_db(struct q2t_tgt *tgt, bool local_only)
 {

scst/include/scst.h

@@ -997,6 +997,19 @@ struct scst_tgt_template {
 	 */
 	ssize_t (*mgmt_cmd) (char *cmd);
 
+	/*
+	 * Forcibly close a session. Note: this function may operate
+	 * asynchronously - there is no guarantee the session will actually
+	 * have been closed at the time this function returns. May be called
+	 * with scst_mutex held. Activity may be suspended while this function
+	 * is invoked. May sleep but must not wait until session
+	 * unregistration finished. Must return 0 upon success and -EINTR if
+	 * the session has not been closed because a signal has been received.
+	 *
+	 * OPTIONAL
+	 */
+	int (*close_session)(struct scst_session *sess);
+
 	/*
 	 * Should return physical transport version. Used in the corresponding
 	 * INQUIRY version descriptor. See SPC for the list of available codes.

scst/src/scst_sysfs.c

@@ -3553,6 +3553,28 @@ SCST_SESS_SYSFS_STAT_ATTR(cmd_count, bidi_cmd_count, SCST_DATA_BIDI, 0);
 SCST_SESS_SYSFS_STAT_ATTR(io_byte_count, bidi_io_count_kb, SCST_DATA_BIDI, 1);
 SCST_SESS_SYSFS_STAT_ATTR(cmd_count, none_cmd_count, SCST_DATA_NONE, 0);
 
+
+static ssize_t scst_sess_force_close_store(struct kobject *kobj,
+					   struct kobj_attribute *attr,
+					   const char *buf, size_t count)
+{
+	struct scst_session *sess = container_of(kobj, struct scst_session,
+						 sess_kobj);
+	int res;
+
+	res = sess->tgt->tgtt->close_session(sess);
+	if (res < 0)
+		goto out;
+	res = count;
+
+out:
+	return res;
+}
+
+static struct kobj_attribute session_force_close_attr =
+	__ATTR(force_close, S_IWUSR, NULL, scst_sess_force_close_store);
+
+
 static struct attribute *scst_session_attrs[] = {
 	&session_commands_attr.attr,
 	&session_active_commands_attr.attr,
@@ -3640,6 +3662,16 @@ int scst_sess_sysfs_create(struct scst_session *sess)
 
 	sess->sess_kobj_ready = 1;
 
+	if (sess->tgt->tgtt->close_session) {
+		res = sysfs_create_file(&sess->sess_kobj,
+					&session_force_close_attr.attr);
+		if (res != 0) {
+			PRINT_ERROR("Adding force_close sysfs attribute to session %s failed (%d)",
+				    name, res);
+			goto out_del;
+		}
+	}
+
 	if (sess->tgt->tgtt->sess_attrs) {
 		res = sysfs_create_files(&sess->sess_kobj,
 					 sess->tgt->tgtt->sess_attrs);

srpt/src/ib_srpt.c

@@ -3528,6 +3528,14 @@ static int srpt_detect(struct scst_tgt_template *tp)
 	return device_count;
 }
 
+static int srpt_close_session(struct scst_session *sess)
+{
+	struct srpt_rdma_ch *ch = scst_sess_get_tgt_priv(sess);
+
+	srpt_close_ch(ch);
+	return 0;
+}
+
 static int srpt_ch_list_empty(struct srpt_tgt *srpt_tgt)
 {
 	int res;
@@ -3752,6 +3760,7 @@ static struct scst_tgt_template srpt_template = {
 	.on_hw_pending_cmd_timeout	 = srpt_pending_cmd_timeout,
 	.on_free_cmd			 = srpt_on_free_cmd,
 	.task_mgmt_fn_done		 = srpt_tsk_mgmt_done,
+	.close_session			 = srpt_close_session,
 	.get_initiator_port_transport_id = srpt_get_initiator_port_transport_id,
 	.get_scsi_transport_version	 = srpt_get_scsi_transport_version,
 };