Avoid that enabling a target too quickly triggers a crash (merge r4515 from trunk)

git-svn-id: http://svn.code.sf.net/p/scst/svn/branches/2.2.x@6079 d57e44dd-8a1f-0410-8b47-8ef2f437770f

fcst/ft_sess.c

@@ -614,7 +614,7 @@ int ft_tgt_enable(struct scst_tgt *tgt, bool enable)
 		FT_SESS_DBG("enable tgt %s\n", tgt->tgt_name);
 		tport = scst_tgt_get_tgt_priv(tgt);
 		if (tport == NULL) {
-			ret = -EBUSY;
+			ret = -E_TGT_PRIV_NOT_YET_SET;
 			goto out_unlock;
 		}
 		tport->enabled = 1;

iscsi-scst/kernel/target.c

@@ -454,19 +454,22 @@ const struct seq_operations iscsi_seq_op = {
 static ssize_t iscsi_tgt_tid_show(struct kobject *kobj,
 	struct kobj_attribute *attr, char *buf)
 {
-	int pos;
+	int res = -E_TGT_PRIV_NOT_YET_SET;
 	struct scst_tgt *scst_tgt;
 	struct iscsi_target *tgt;
 
 	TRACE_ENTRY();
 
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
-	tgt = (struct iscsi_target *)scst_tgt_get_tgt_priv(scst_tgt);
+	tgt = scst_tgt_get_tgt_priv(scst_tgt);
+	if (!tgt)
+		goto out;
 
-	pos = sprintf(buf, "%u\n", tgt->tid);
+	res = sprintf(buf, "%u\n", tgt->tid);
 
-	TRACE_EXIT_RES(pos);
-	return pos;
+out:
+	TRACE_EXIT_RES(res);
+	return res;
 }
 
 static struct kobj_attribute iscsi_tgt_attr_tid =
@@ -532,6 +535,11 @@ int iscsi_enable_target(struct scst_tgt *scst_tgt, bool enable)
 
 	TRACE_ENTRY();
 
+	if (tgt == NULL) {
+		res = -E_TGT_PRIV_NOT_YET_SET;
+		goto out;
+	}
+
 	if (enable)
 		type = E_ENABLE_TARGET;
 	else
@@ -541,6 +549,7 @@ int iscsi_enable_target(struct scst_tgt *scst_tgt, bool enable)
 
 	res = iscsi_sysfs_send_event(tgt->tid, type, NULL, NULL, NULL);
 
+out:
 	TRACE_EXIT_RES(res);
 	return res;
 }
@@ -550,7 +559,10 @@ bool iscsi_is_target_enabled(struct scst_tgt *scst_tgt)
 	struct iscsi_target *tgt =
 		(struct iscsi_target *)scst_tgt_get_tgt_priv(scst_tgt);
 
-	return tgt->tgt_enabled;
+	if (tgt != NULL)
+		return tgt->tgt_enabled;
+	else
+		return false;
 }
 
 ssize_t iscsi_sysfs_add_target(const char *target_name, char *params)

qla2x00t/qla2x00-target/qla2x00t.c

@@ -6090,23 +6090,31 @@ out:
 static int q2t_enable_tgt(struct scst_tgt *scst_tgt, bool enable)
 {
 	struct q2t_tgt *tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
-	scsi_qla_host_t *ha = tgt->ha;
-	int res;
+	scsi_qla_host_t *ha;
+	int res = -E_TGT_PRIV_NOT_YET_SET;
+
+	if (tgt == NULL)
+		goto out;
+
+	ha = tgt->ha;
 
 	if (enable)
 		res = q2t_host_action(ha, ENABLE_TARGET_MODE);
 	else
 		res = q2t_host_action(ha, DISABLE_TARGET_MODE);
 
+out:
 	return res;
 }
 
 static bool q2t_is_tgt_enabled(struct scst_tgt *scst_tgt)
 {
 	struct q2t_tgt *tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
-	scsi_qla_host_t *ha = tgt->ha;
 
-	return qla_tgt_mode_enabled(ha);
+	if (tgt == NULL)
+		return false;
+
+	return qla_tgt_mode_enabled(tgt->ha);
 }
 
 #if ((LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)) || \
@@ -6314,16 +6322,19 @@ static ssize_t q2t_show_expl_conf_enabled(struct kobject *kobj,
 	struct scst_tgt *scst_tgt;
 	struct q2t_tgt *tgt;
 	scsi_qla_host_t *ha;
-	ssize_t size;
+	int res = -E_TGT_PRIV_NOT_YET_SET;
 
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
-	tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
+	tgt = scst_tgt_get_tgt_priv(scst_tgt);
+	if (!tgt)
+		goto out;
 	ha = tgt->ha;
 
-	size = scnprintf(buffer, PAGE_SIZE, "%d\n%s", ha->enable_explicit_conf,
+	res = scnprintf(buffer, PAGE_SIZE, "%d\n%s", ha->enable_explicit_conf,
 		ha->enable_explicit_conf ? SCST_SYSFS_KEY_MARK "\n" : "");
 
-	return size;
+out:
+	return res;
 }
 
 static ssize_t q2t_store_expl_conf_enabled(struct kobject *kobj,
@@ -6332,10 +6343,13 @@ static ssize_t q2t_store_expl_conf_enabled(struct kobject *kobj,
 	struct scst_tgt *scst_tgt;
 	struct q2t_tgt *tgt;
 	scsi_qla_host_t *ha, *pha;
+	int res = -E_TGT_PRIV_NOT_YET_SET;
 	unsigned long flags;
 
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
-	tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
+	tgt = scst_tgt_get_tgt_priv(scst_tgt);
+	if (!tgt)
+		goto out;
 	ha = tgt->ha;
 	pha = to_qla_parent(ha);
 
@@ -6360,7 +6374,10 @@ static ssize_t q2t_store_expl_conf_enabled(struct kobject *kobj,
 
 	spin_unlock_irqrestore(&pha->hardware_lock, flags);
 
-	return size;
+	res = size;
+
+out:
+	return res;
 }
 
 static ssize_t q2t_abort_isp_store(struct kobject *kobj,
@@ -6369,9 +6386,12 @@ static ssize_t q2t_abort_isp_store(struct kobject *kobj,
 	struct scst_tgt *scst_tgt;
 	struct q2t_tgt *tgt;
 	scsi_qla_host_t *ha;
+	int res = -E_TGT_PRIV_NOT_YET_SET;
 
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
-	tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
+	tgt = scst_tgt_get_tgt_priv(scst_tgt);
+	if (!tgt)
+		goto out;
 	ha = tgt->ha;
 
 	PRINT_INFO("qla2x00t(%ld): Aborting ISP", ha->instance);
@@ -6379,7 +6399,10 @@ static ssize_t q2t_abort_isp_store(struct kobject *kobj,
 	set_bit(ISP_ABORT_NEEDED, &ha->dpc_flags);
 	qla2x00_wait_for_hba_online(ha);
 
-	return size;
+	res = size;
+
+out:
+	return res;
 }
 
 static ssize_t q2t_version_show(struct kobject *kobj,
@@ -6419,12 +6442,14 @@ static ssize_t q2t_node_name_show(struct kobject *kobj,
 	struct scst_tgt *scst_tgt;
 	struct q2t_tgt *tgt;
 	scsi_qla_host_t *ha;
-	ssize_t res;
+	ssize_t res = -E_TGT_PRIV_NOT_YET_SET;
 	char *wwn;
 	uint8_t *node_name;
 
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
-	tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
+	tgt = scst_tgt_get_tgt_priv(scst_tgt);
+	if (!tgt)
+		goto out;
 	ha = tgt->ha;
 
 	if (ha->parent == NULL) {
@@ -6456,12 +6481,14 @@ static ssize_t q2t_node_name_store(struct kobject *kobj,
 	struct q2t_tgt *tgt;
 	scsi_qla_host_t *ha;
 	u64 node_name, old_node_name;
-	int res;
+	int res = -E_TGT_PRIV_NOT_YET_SET;
 
 	TRACE_ENTRY();
 
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
-	tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
+	tgt = scst_tgt_get_tgt_priv(scst_tgt);
+	if (!tgt)
+		goto out;
 	ha = tgt->ha;
 
 	sBUG_ON(ha->parent != NULL);
@@ -6508,11 +6535,13 @@ static ssize_t q2t_vp_parent_host_show(struct kobject *kobj,
 	struct scst_tgt *scst_tgt;
 	struct q2t_tgt *tgt;
 	scsi_qla_host_t *ha;
-	ssize_t res;
+	ssize_t res = -E_TGT_PRIV_NOT_YET_SET;
 	char *wwn;
 
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
-	tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
+	tgt = scst_tgt_get_tgt_priv(scst_tgt);
+	if (!tgt)
+		goto out;
 	ha = to_qla_parent(tgt->ha);
 
 	res = q2t_get_target_name(ha->port_name, &wwn);

scst/include/scst_const.h

@@ -31,6 +31,10 @@
 #endif
 #include <scsi/scsi.h>
 
+#ifndef __KERNEL__
+#include <errno.h>
+#endif
+
 /*
  * Version numbers, the same as for the kernel.
  *
@@ -519,4 +523,13 @@ enum scst_tg_sup {
 #define SCST_MIN_REL_TGT_ID			1
 #define SCST_MAX_REL_TGT_ID			65535
 
+/*
+ * Error code returned by target attribute sysfs methods if invoked after
+ * scst_register_target() finished but before before scst_tgt_set_tgt_priv()
+ * has been invoked.
+ */
+enum {
+	E_TGT_PRIV_NOT_YET_SET = EBUSY
+};
+
 #endif /* __SCST_CONST_H */

scst_local/scst_local.c

@@ -408,6 +408,8 @@ static ssize_t scst_local_scsi_transport_version_show(struct kobject *kobj,
 	if (down_read_trylock(&scst_local_exit_rwsem) == 0)
 		goto out;
 
+	res = -E_TGT_PRIV_NOT_YET_SET;
+
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
 	tgt = scst_tgt_get_tgt_priv(scst_tgt);
 	if (!tgt)
@@ -436,6 +438,8 @@ static ssize_t scst_local_scsi_transport_version_store(struct kobject *kobj,
 	if (down_read_trylock(&scst_local_exit_rwsem) == 0)
 		goto out;
 
+	res = -E_TGT_PRIV_NOT_YET_SET;
+
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
 	tgt = scst_tgt_get_tgt_priv(scst_tgt);
 	if (!tgt)
@@ -476,6 +480,8 @@ static ssize_t scst_local_phys_transport_version_show(struct kobject *kobj,
 	if (down_read_trylock(&scst_local_exit_rwsem) == 0)
 		goto out;
 
+	res = -E_TGT_PRIV_NOT_YET_SET;
+
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
 	tgt = scst_tgt_get_tgt_priv(scst_tgt);
 	if (!tgt)
@@ -502,6 +508,8 @@ static ssize_t scst_local_phys_transport_version_store(struct kobject *kobj,
 	if (down_read_trylock(&scst_local_exit_rwsem) == 0)
 		goto out;
 
+	res = -E_TGT_PRIV_NOT_YET_SET;
+
 	scst_tgt = container_of(kobj, struct scst_tgt, tgt_kobj);
 	tgt = scst_tgt_get_tgt_priv(scst_tgt);
 	if (!tgt)
@@ -1547,6 +1555,11 @@ static uint16_t scst_local_get_scsi_transport_version(struct scst_tgt *scst_tgt)
 {
 	struct scst_local_tgt *tgt = scst_tgt_get_tgt_priv(scst_tgt);
 
+	/*
+	 * It's OK to not check tgt != NULL here, because new sessions
+	 * can't create before its' set.
+	 */
+
 	if (tgt->scsi_transport_version == 0)
 		return 0x0BE0; /* SAS */
 	else
@@ -1557,6 +1570,11 @@ static uint16_t scst_local_get_phys_transport_version(struct scst_tgt *scst_tgt)
 {
 	struct scst_local_tgt *tgt = scst_tgt_get_tgt_priv(scst_tgt);
 
+	/*
+	 * It's OK to not check tgt != NULL here, because new sessions
+	 * can't create before its' set.
+	 */
+
 	return tgt->phys_transport_version;
 }
 

srpt/src/ib_srpt.c

@@ -2333,7 +2333,7 @@ static int srpt_enable_target(struct scst_tgt *scst_tgt, bool enable)
 	EXTRACHECKS_WARN_ON_ONCE(irqs_disabled());
 
 	if (!sdev)
-		return -ENOENT;
+		return -E_TGT_PRIV_NOT_YET_SET;
 
 	TRACE_DBG("%s target %s", enable ? "Enabling" : "Disabling",
 		  sdev->device->name);