iscsi-target: Convert to per-cpu ida_alloc + ida_free command map

This patch changes iscsi-target to use transport_alloc_session_tags()
pre-allocation logic for per-cpu session tag pooling with internal
ida_alloc() + ida_free() calls based upon the saved se_cmd->map_tag id.

This includes tag pool setup based upon per NodeACL queue_depth after
locating se_node_acl in iscsi_target_locate_portal().

Also update iscsit_allocate_cmd() and iscsit_release_cmd() to use
percpu_ida_alloc() and percpu_ida_free() respectively.

v5 changes;
  - Convert to percpu_ida.h include

v2 changes:
  - Fix bug with SessionType=Discovery in iscsi_target_locate_portal()

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

1 files changed, 24 insertions, 4 deletions

diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index 2cce636d1113..24b0e33e7c50 100644
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -983,8 +983,9 @@ int iscsi_target_locate_portal(
 	struct iscsi_tiqn *tiqn;
 	struct iscsi_tpg_np *tpg_np = NULL;
 	struct iscsi_login_req *login_req;
-	u32 payload_length;
-	int sessiontype = 0, ret = 0;
+	struct se_node_acl *se_nacl;
+	u32 payload_length, queue_depth = 0;
+	int sessiontype = 0, ret = 0, tag_num, tag_size;
 
 	INIT_DELAYED_WORK(&conn->login_work, iscsi_target_do_login_rx);
 	INIT_DELAYED_WORK(&conn->login_cleanup_work, iscsi_target_do_cleanup);
@@ -1084,7 +1085,7 @@ int iscsi_target_locate_portal(
 			goto out;
 		}
 		ret = 0;
-		goto out;
+		goto alloc_tags;
 	}
 
 get_target:
@@ -1181,8 +1182,27 @@ get_target:
 		ret = -1;
 		goto out;
 	}
+	se_nacl = sess->se_sess->se_node_acl;
+	queue_depth = se_nacl->queue_depth;
+	/*
+	 * Setup pre-allocated tags based upon allowed per NodeACL CmdSN
+	 * depth for non immediate commands, plus extra tags for immediate
+	 * commands.
+	 *
+	 * Also enforce a ISCSIT_MIN_TAGS to prevent unnecessary contention
+	 * in per-cpu-ida tag allocation logic + small queue_depth.
+	 */
+alloc_tags:
+	tag_num = max_t(u32, ISCSIT_MIN_TAGS, queue_depth);
+	tag_num += ISCSIT_EXTRA_TAGS;
+	tag_size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size;
 
-	ret = 0;
+	ret = transport_alloc_session_tags(sess->se_sess, tag_num, tag_size);
+	if (ret < 0) {
+		iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
+				    ISCSI_LOGIN_STATUS_NO_RESOURCES);
+		ret = -1;
+	}
 out:
 	kfree(tmpbuf);
 	return ret;