Revert "cifs: reconnect work should have reference on server struct"

This reverts commit 19a4b9d.

This earlier commit was making an assumption that each mod_delayed_work
called for the reconnect work would result in smb2_reconnect_server
being called twice. This assumption turns out to be untrue. So reverting
this change for now.

I will submit a follow-up patch to fix the actual problem in a different
way.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: sprasad-microsoft

fs/smb/client/connect.c

@@ -402,13 +402,7 @@ static int __cifs_reconnect(struct TCP_Server_Info *server,
 			spin_unlock(&server->srv_lock);
 			cifs_swn_reset_server_dstaddr(server);
 			cifs_server_unlock(server);
-
-			/* increase ref count which reconnect work will drop */
-			spin_lock(&cifs_tcp_ses_lock);
-			server->srv_count++;
-			spin_unlock(&cifs_tcp_ses_lock);
-			if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0))
-				cifs_put_tcp_session(server, false);
+			mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 		}
 	} while (server->tcpStatus == CifsNeedReconnect);
 
@@ -538,13 +532,7 @@ static int reconnect_dfs_server(struct TCP_Server_Info *server)
 		spin_unlock(&server->srv_lock);
 		cifs_swn_reset_server_dstaddr(server);
 		cifs_server_unlock(server);
-
-		/* increase ref count which reconnect work will drop */
-		spin_lock(&cifs_tcp_ses_lock);
-		server->srv_count++;
-		spin_unlock(&cifs_tcp_ses_lock);
-		if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0))
-			cifs_put_tcp_session(server, false);
+		mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 	} while (server->tcpStatus == CifsNeedReconnect);
 
 	mutex_lock(&server->refpath_lock);
@@ -1626,19 +1614,16 @@ cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
 
 	cancel_delayed_work_sync(&server->echo);
 
-	if (from_reconnect) {
+	if (from_reconnect)
 		/*
 		 * Avoid deadlock here: reconnect work calls
 		 * cifs_put_tcp_session() at its end. Need to be sure
 		 * that reconnect work does nothing with server pointer after
 		 * that step.
 		 */
-		if (cancel_delayed_work(&server->reconnect))
-			cifs_put_tcp_session(server, from_reconnect);
-	} else {
-		if (cancel_delayed_work_sync(&server->reconnect))
-			cifs_put_tcp_session(server, from_reconnect);
-	}
+		cancel_delayed_work(&server->reconnect);
+	else
+		cancel_delayed_work_sync(&server->reconnect);
 
 	spin_lock(&server->srv_lock);
 	server->tcpStatus = CifsExiting;

fs/smb/client/smb2pdu.c

@@ -3952,6 +3952,12 @@ void smb2_reconnect_server(struct work_struct *work)
 		}
 		spin_unlock(&ses->chan_lock);
 	}
+	/*
+	 * Get the reference to server struct to be sure that the last call of
+	 * cifs_put_tcon() in the loop below won't release the server pointer.
+	 */
+	if (tcon_exist || ses_exist)
+		server->srv_count++;
 
 	spin_unlock(&cifs_tcp_ses_lock);
 
@@ -3999,17 +4005,13 @@ void smb2_reconnect_server(struct work_struct *work)
 
 done:
 	cifs_dbg(FYI, "Reconnecting tcons and channels finished\n");
-	if (resched) {
+	if (resched)
 		queue_delayed_work(cifsiod_wq, &server->reconnect, 2 * HZ);
-		mutex_unlock(&pserver->reconnect_mutex);
-
-		/* no need to put tcp session as we're retrying */
-		return;
-	}
 	mutex_unlock(&pserver->reconnect_mutex);
 
 	/* now we can safely release srv struct */
-	cifs_put_tcp_session(server, true);
+	if (tcon_exist || ses_exist)
+		cifs_put_tcp_session(server, 1);
 }
 
 int
@@ -4029,12 +4031,7 @@ SMB2_echo(struct TCP_Server_Info *server)
 	    server->ops->need_neg(server)) {
 		spin_unlock(&server->srv_lock);
 		/* No need to send echo on newly established connections */
-		spin_lock(&cifs_tcp_ses_lock);
-		server->srv_count++;
-		spin_unlock(&cifs_tcp_ses_lock);
-		if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0))
-			cifs_put_tcp_session(server, false);
-
+		mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 		return rc;
 	}
 	spin_unlock(&server->srv_lock);