ksmbd: replace sessions list in connection with xarray

Replace sessions list in connection with xarray.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/connection.c

@@ -36,6 +36,7 @@ void ksmbd_conn_free(struct ksmbd_conn *conn)
 	list_del(&conn->conns_list);
 	write_unlock(&conn_list_lock);
 
+	xa_destroy(&conn->sessions);
 	kvfree(conn->request_buf);
 	kfree(conn->preauth_info);
 	kfree(conn);
@@ -66,12 +67,12 @@ struct ksmbd_conn *ksmbd_conn_alloc(void)
 
 	init_waitqueue_head(&conn->req_running_q);
 	INIT_LIST_HEAD(&conn->conns_list);
-	INIT_LIST_HEAD(&conn->sessions);
 	INIT_LIST_HEAD(&conn->requests);
 	INIT_LIST_HEAD(&conn->async_requests);
 	spin_lock_init(&conn->request_lock);
 	spin_lock_init(&conn->credits_lock);
 	ida_init(&conn->async_ida);
+	xa_init(&conn->sessions);
 
 	spin_lock_init(&conn->llist_lock);
 	INIT_LIST_HEAD(&conn->lock_list);

fs/ksmbd/connection.h

@@ -55,7 +55,7 @@ struct ksmbd_conn {
 	struct nls_table		*local_nls;
 	struct list_head		conns_list;
 	/* smb session 1 per user */
-	struct list_head		sessions;
+	struct xarray			sessions;
 	unsigned long			last_active;
 	/* How many request are running currently */
 	atomic_t			req_running;

fs/ksmbd/mgmt/user_session.c

@@ -152,8 +152,6 @@ void ksmbd_session_destroy(struct ksmbd_session *sess)
 	if (!atomic_dec_and_test(&sess->refcnt))
 		return;
 
-	list_del(&sess->sessions_entry);
-
 	down_write(&sessions_table_lock);
 	hash_del(&sess->hlist);
 	up_write(&sessions_table_lock);
@@ -181,42 +179,28 @@ static struct ksmbd_session *__session_lookup(unsigned long long id)
 	return NULL;
 }
 
-void ksmbd_session_register(struct ksmbd_conn *conn,
-			    struct ksmbd_session *sess)
+int ksmbd_session_register(struct ksmbd_conn *conn,
+			   struct ksmbd_session *sess)
 {
 	sess->conn = conn;
-	list_add(&sess->sessions_entry, &conn->sessions);
+	return xa_err(xa_store(&conn->sessions, sess->id, sess, GFP_KERNEL));
 }
 
 void ksmbd_sessions_deregister(struct ksmbd_conn *conn)
 {
 	struct ksmbd_session *sess;
+	unsigned long id;
 
-	while (!list_empty(&conn->sessions)) {
-		sess = list_entry(conn->sessions.next,
-				  struct ksmbd_session,
-				  sessions_entry);
-
+	xa_for_each(&conn->sessions, id, sess) {
+		xa_erase(&conn->sessions, sess->id);
 		ksmbd_session_destroy(sess);
 	}
 }
 
-static bool ksmbd_session_id_match(struct ksmbd_session *sess,
-				   unsigned long long id)
-{
-	return sess->id == id;
-}
-
 struct ksmbd_session *ksmbd_session_lookup(struct ksmbd_conn *conn,
 					   unsigned long long id)
 {
-	struct ksmbd_session *sess = NULL;
-
-	list_for_each_entry(sess, &conn->sessions, sessions_entry) {
-		if (ksmbd_session_id_match(sess, id))
-			return sess;
-	}
-	return NULL;
+	return xa_load(&conn->sessions, id);
 }
 
 int get_session(struct ksmbd_session *sess)
@@ -314,7 +298,6 @@ static struct ksmbd_session *__session_create(int protocol)
 		goto error;
 
 	set_session_flag(sess, protocol);
-	INIT_LIST_HEAD(&sess->sessions_entry);
 	xa_init(&sess->tree_conns);
 	INIT_LIST_HEAD(&sess->ksmbd_chann_list);
 	INIT_LIST_HEAD(&sess->rpc_handle_list);

fs/ksmbd/mgmt/user_session.h

@@ -57,7 +57,6 @@ struct ksmbd_session {
 	__u8				smb3decryptionkey[SMB3_ENC_DEC_KEY_SIZE];
 	__u8				smb3signingkey[SMB3_SIGN_KEY_SIZE];
 
-	struct list_head		sessions_entry;
 	struct ksmbd_file_table		file_table;
 	atomic_t			refcnt;
 };
@@ -84,8 +83,8 @@ void ksmbd_session_destroy(struct ksmbd_session *sess);
 struct ksmbd_session *ksmbd_session_lookup_slowpath(unsigned long long id);
 struct ksmbd_session *ksmbd_session_lookup(struct ksmbd_conn *conn,
 					   unsigned long long id);
-void ksmbd_session_register(struct ksmbd_conn *conn,
-			    struct ksmbd_session *sess);
+int ksmbd_session_register(struct ksmbd_conn *conn,
+			   struct ksmbd_session *sess);
 void ksmbd_sessions_deregister(struct ksmbd_conn *conn);
 struct ksmbd_session *ksmbd_session_lookup_all(struct ksmbd_conn *conn,
 					       unsigned long long id);

fs/ksmbd/smb2pdu.c

@@ -588,7 +588,8 @@ int smb2_check_user_session(struct ksmbd_work *work)
 	return -EINVAL;
 }
 
-static void destroy_previous_session(struct ksmbd_user *user, u64 id)
+static void destroy_previous_session(struct ksmbd_conn *conn,
+				     struct ksmbd_user *user, u64 id)
 {
 	struct ksmbd_session *prev_sess = ksmbd_session_lookup_slowpath(id);
 	struct ksmbd_user *prev_user;
@@ -607,6 +608,7 @@ static void destroy_previous_session(struct ksmbd_user *user, u64 id)
 	}
 
 	put_session(prev_sess);
+	xa_erase(&conn->sessions, prev_sess->id);
 	ksmbd_session_destroy(prev_sess);
 }
 
@@ -1439,7 +1441,7 @@ static int ntlm_authenticate(struct ksmbd_work *work)
 	/* Check for previous session */
 	prev_id = le64_to_cpu(req->PreviousSessionId);
 	if (prev_id && prev_id != sess->id)
-		destroy_previous_session(user, prev_id);
+		destroy_previous_session(conn, user, prev_id);
 
 	if (sess->state == SMB2_SESSION_VALID) {
 		/*
@@ -1561,7 +1563,7 @@ static int krb5_authenticate(struct ksmbd_work *work)
 	/* Check previous session */
 	prev_sess_id = le64_to_cpu(req->PreviousSessionId);
 	if (prev_sess_id && prev_sess_id != sess->id)
-		destroy_previous_session(sess->user, prev_sess_id);
+		destroy_previous_session(conn, sess->user, prev_sess_id);
 
 	if (sess->state == SMB2_SESSION_VALID)
 		ksmbd_free_user(sess->user);
@@ -1650,7 +1652,9 @@ int smb2_sess_setup(struct ksmbd_work *work)
 			goto out_err;
 		}
 		rsp->hdr.SessionId = cpu_to_le64(sess->id);
-		ksmbd_session_register(conn, sess);
+		rc = ksmbd_session_register(conn, sess);
+		if (rc)
+			goto out_err;
 	} else if (conn->dialect >= SMB30_PROT_ID &&
 		   (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB3_MULTICHANNEL) &&
 		   req->Flags & SMB2_SESSION_REQ_FLAG_BINDING) {
@@ -1828,6 +1832,7 @@ int smb2_sess_setup(struct ksmbd_work *work)
 			if (sess->user && sess->user->flags & KSMBD_USER_FLAG_DELAY_SESSION)
 				try_delay = true;
 
+			xa_erase(&conn->sessions, sess->id);
 			ksmbd_session_destroy(sess);
 			work->sess = NULL;
 			if (try_delay)