target_core_alua: Allocate ALUA metadata on demand

We should only allocate ALUA metadata if we're actually going
to write them.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_alua.c

@@ -770,16 +770,22 @@ static int core_alua_write_tpg_metadata(
  */
 static int core_alua_update_tpg_primary_metadata(
 	struct t10_alua_tg_pt_gp *tg_pt_gp,
-	int primary_state,
-	unsigned char *md_buf)
+	int primary_state)
 {
+	unsigned char *md_buf;
 	struct t10_wwn *wwn = &tg_pt_gp->tg_pt_gp_dev->t10_wwn;
 	char path[ALUA_METADATA_PATH_LEN];
-	int len;
+	int len, rc;
+
+	md_buf = kzalloc(ALUA_MD_BUF_LEN, GFP_KERNEL);
+	if (!md_buf) {
+		pr_err("Unable to allocate buf for ALUA metadata\n");
+		return -ENOMEM;
+	}
 
 	memset(path, 0, ALUA_METADATA_PATH_LEN);
 
-	len = snprintf(md_buf, tg_pt_gp->tg_pt_gp_md_buf_len,
+	len = snprintf(md_buf, ALUA_MD_BUF_LEN,
 			"tg_pt_gp_id=%hu\n"
 			"alua_access_state=0x%02x\n"
 			"alua_access_status=0x%02x\n",
@@ -790,14 +796,15 @@ static int core_alua_update_tpg_primary_metadata(
 		"/var/target/alua/tpgs_%s/%s", &wwn->unit_serial[0],
 		config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item));
 
-	return core_alua_write_tpg_metadata(path, md_buf, len);
+	rc = core_alua_write_tpg_metadata(path, md_buf, len);
+	kfree(md_buf);
+	return rc;
 }
 
 static int core_alua_do_transition_tg_pt(
 	struct t10_alua_tg_pt_gp *tg_pt_gp,
 	struct se_port *l_port,
 	struct se_node_acl *nacl,
-	unsigned char *md_buf,
 	int new_state,
 	int explicit)
 {
@@ -885,8 +892,7 @@ static int core_alua_do_transition_tg_pt(
 	 */
 	if (tg_pt_gp->tg_pt_gp_write_metadata) {
 		mutex_lock(&tg_pt_gp->tg_pt_gp_md_mutex);
-		core_alua_update_tpg_primary_metadata(tg_pt_gp,
-					new_state, md_buf);
+		core_alua_update_tpg_primary_metadata(tg_pt_gp, new_state);
 		mutex_unlock(&tg_pt_gp->tg_pt_gp_md_mutex);
 	}
 	/*
@@ -917,19 +923,12 @@ int core_alua_do_port_transition(
 	struct t10_alua_lu_gp *lu_gp;
 	struct t10_alua_lu_gp_member *lu_gp_mem, *local_lu_gp_mem;
 	struct t10_alua_tg_pt_gp *tg_pt_gp;
-	unsigned char *md_buf;
 	int primary, valid_states;
 
 	valid_states = l_tg_pt_gp->tg_pt_gp_alua_supported_states;
 	if (core_alua_check_transition(new_state, valid_states, &primary) != 0)
 		return -EINVAL;
 
-	md_buf = kzalloc(l_tg_pt_gp->tg_pt_gp_md_buf_len, GFP_KERNEL);
-	if (!md_buf) {
-		pr_err("Unable to allocate buf for ALUA metadata\n");
-		return -ENOMEM;
-	}
-
 	local_lu_gp_mem = l_dev->dev_alua_lu_gp_mem;
 	spin_lock(&local_lu_gp_mem->lu_gp_mem_lock);
 	lu_gp = local_lu_gp_mem->lu_gp;
@@ -947,10 +946,9 @@ int core_alua_do_port_transition(
 		 * success.
 		 */
 		core_alua_do_transition_tg_pt(l_tg_pt_gp, l_port, l_nacl,
-					md_buf, new_state, explicit);
+					new_state, explicit);
 		atomic_dec(&lu_gp->lu_gp_ref_cnt);
 		smp_mb__after_atomic_dec();
-		kfree(md_buf);
 		return 0;
 	}
 	/*
@@ -1000,7 +998,7 @@ int core_alua_do_port_transition(
 			 * success.
 			 */
 			core_alua_do_transition_tg_pt(tg_pt_gp, port,
-					nacl, md_buf, new_state, explicit);
+					nacl, new_state, explicit);
 
 			spin_lock(&dev->t10_alua.tg_pt_gps_lock);
 			atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
@@ -1022,7 +1020,6 @@ int core_alua_do_port_transition(
 
 	atomic_dec(&lu_gp->lu_gp_ref_cnt);
 	smp_mb__after_atomic_dec();
-	kfree(md_buf);
 	return 0;
 }
 
@@ -1031,13 +1028,18 @@ int core_alua_do_port_transition(
  */
 static int core_alua_update_tpg_secondary_metadata(
 	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
-	struct se_port *port,
-	unsigned char *md_buf,
-	u32 md_buf_len)
+	struct se_port *port)
 {
+	unsigned char *md_buf;
 	struct se_portal_group *se_tpg = port->sep_tpg;
 	char path[ALUA_METADATA_PATH_LEN], wwn[ALUA_SECONDARY_METADATA_WWN_LEN];
-	int len;
+	int len, rc;
+
+	md_buf = kzalloc(ALUA_MD_BUF_LEN, GFP_KERNEL);
+	if (!md_buf) {
+		pr_err("Unable to allocate buf for ALUA metadata\n");
+		return -ENOMEM;
+	}
 
 	memset(path, 0, ALUA_METADATA_PATH_LEN);
 	memset(wwn, 0, ALUA_SECONDARY_METADATA_WWN_LEN);
@@ -1049,7 +1051,7 @@ static int core_alua_update_tpg_secondary_metadata(
 		snprintf(wwn+len, ALUA_SECONDARY_METADATA_WWN_LEN-len, "+%hu",
 				se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
 
-	len = snprintf(md_buf, md_buf_len, "alua_tg_pt_offline=%d\n"
+	len = snprintf(md_buf, ALUA_MD_BUF_LEN, "alua_tg_pt_offline=%d\n"
 			"alua_tg_pt_status=0x%02x\n",
 			atomic_read(&port->sep_tg_pt_secondary_offline),
 			port->sep_tg_pt_secondary_stat);
@@ -1058,7 +1060,10 @@ static int core_alua_update_tpg_secondary_metadata(
 			se_tpg->se_tpg_tfo->get_fabric_name(), wwn,
 			port->sep_lun->unpacked_lun);
 
-	return core_alua_write_tpg_metadata(path, md_buf, len);
+	rc = core_alua_write_tpg_metadata(path, md_buf, len);
+	kfree(md_buf);
+
+	return rc;
 }
 
 static int core_alua_set_tg_pt_secondary_state(
@@ -1068,8 +1073,6 @@ static int core_alua_set_tg_pt_secondary_state(
 	int offline)
 {
 	struct t10_alua_tg_pt_gp *tg_pt_gp;
-	unsigned char *md_buf;
-	u32 md_buf_len;
 	int trans_delay_msecs;
 
 	spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
@@ -1090,7 +1093,6 @@ static int core_alua_set_tg_pt_secondary_state(
 	else
 		atomic_set(&port->sep_tg_pt_secondary_offline, 0);
 
-	md_buf_len = tg_pt_gp->tg_pt_gp_md_buf_len;
 	port->sep_tg_pt_secondary_stat = (explicit) ?
 			ALUA_STATUS_ALTERED_BY_EXPLICIT_STPG :
 			ALUA_STATUS_ALTERED_BY_IMPLICIT_ALUA;
@@ -1112,18 +1114,9 @@ static int core_alua_set_tg_pt_secondary_state(
 	 * secondary state and status
 	 */
 	if (port->sep_tg_pt_secondary_write_md) {
-		md_buf = kzalloc(md_buf_len, GFP_KERNEL);
-		if (!md_buf) {
-			pr_err("Unable to allocate md_buf for"
-				" secondary ALUA access metadata\n");
-			return -ENOMEM;
-		}
 		mutex_lock(&port->sep_tg_pt_md_mutex);
-		core_alua_update_tpg_secondary_metadata(tg_pt_gp_mem, port,
-				md_buf, md_buf_len);
+		core_alua_update_tpg_secondary_metadata(tg_pt_gp_mem, port);
 		mutex_unlock(&port->sep_tg_pt_md_mutex);
-
-		kfree(md_buf);
 	}
 
 	return 0;
@@ -1382,7 +1375,6 @@ struct t10_alua_tg_pt_gp *core_alua_allocate_tg_pt_gp(struct se_device *dev,
 	spin_lock_init(&tg_pt_gp->tg_pt_gp_lock);
 	atomic_set(&tg_pt_gp->tg_pt_gp_ref_cnt, 0);
 	tg_pt_gp->tg_pt_gp_dev = dev;
-	tg_pt_gp->tg_pt_gp_md_buf_len = ALUA_MD_BUF_LEN;
 	atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
 		ALUA_ACCESS_STATE_ACTIVE_OPTIMIZED);
 	/*

drivers/target/target_core_alua.h

@@ -78,6 +78,9 @@
  */
 #define ALUA_SECONDARY_METADATA_WWN_LEN			256
 
+/* Used by core_alua_update_tpg_(primary,secondary)_metadata */
+#define ALUA_MD_BUF_LEN					1024
+
 extern struct kmem_cache *t10_alua_lu_gp_cache;
 extern struct kmem_cache *t10_alua_lu_gp_mem_cache;
 extern struct kmem_cache *t10_alua_tg_pt_gp_cache;

include/target/target_core_base.h

@@ -291,9 +291,6 @@ struct t10_alua_tg_pt_gp {
 	int	tg_pt_gp_implicit_trans_secs;
 	int	tg_pt_gp_pref;
 	int	tg_pt_gp_write_metadata;
-	/* Used by struct t10_alua_tg_pt_gp->tg_pt_gp_md_buf_len */
-#define ALUA_MD_BUF_LEN				1024
-	u32	tg_pt_gp_md_buf_len;
 	u32	tg_pt_gp_members;
 	atomic_t tg_pt_gp_alua_access_state;
 	atomic_t tg_pt_gp_ref_cnt;