cifs: get rid of dns resolve worker

We already upcall to resolve hostnames during reconnect by calling
reconn_set_ipaddr_from_hostname(), so there is no point in having a
worker to periodically call it.
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsglob.h

@@ -77,10 +77,6 @@
 #define SMB_ECHO_INTERVAL_MAX 600
 #define SMB_ECHO_INTERVAL_DEFAULT 60
 
-/* dns resolution intervals in seconds */
-#define SMB_DNS_RESOLVE_INTERVAL_MIN     120
-#define SMB_DNS_RESOLVE_INTERVAL_DEFAULT 600
-
 /* smb multichannel query server interfaces interval in seconds */
 #define SMB_INTERFACE_POLL_INTERVAL	600
 
@@ -691,7 +687,6 @@ struct TCP_Server_Info {
 	/* point to the SMBD connection if RDMA is used instead of socket */
 	struct smbd_connection *smbd_conn;
 	struct delayed_work	echo; /* echo ping workqueue job */
-	struct delayed_work	resolve; /* dns resolution workqueue job */
 	char	*smallbuf;	/* pointer to current "small" buffer */
 	char	*bigbuf;	/* pointer to current "big" buffer */
 	/* Total size of this PDU. Only valid from cifs_demultiplex_thread */

fs/cifs/connect.c

@@ -79,8 +79,6 @@ static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
 	int len;
 	char *unc;
 	struct sockaddr_storage ss;
-	time64_t expiry, now;
-	unsigned long ttl = SMB_DNS_RESOLVE_INTERVAL_DEFAULT;
 
 	if (!server->hostname)
 		return -EINVAL;
@@ -102,29 +100,19 @@ static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
 	ss = server->dstaddr;
 	spin_unlock(&server->srv_lock);
 
-	rc = dns_resolve_server_name_to_ip(unc, (struct sockaddr *)&ss, &expiry);
+	rc = dns_resolve_server_name_to_ip(unc, (struct sockaddr *)&ss, NULL);
 	kfree(unc);
 
 	if (rc < 0) {
 		cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",
 			 __func__, server->hostname, rc);
-		goto requeue_resolve;
+	} else {
+		spin_lock(&server->srv_lock);
+		memcpy(&server->dstaddr, &ss, sizeof(server->dstaddr));
+		spin_unlock(&server->srv_lock);
+		rc = 0;
 	}
 
-	spin_lock(&server->srv_lock);
-	memcpy(&server->dstaddr, &ss, sizeof(server->dstaddr));
-	spin_unlock(&server->srv_lock);
-
-	now = ktime_get_real_seconds();
-	if (expiry && expiry > now)
-		/* To make sure we don't use the cached entry, retry 1s */
-		ttl = max_t(unsigned long, expiry - now, SMB_DNS_RESOLVE_INTERVAL_MIN) + 1;
-
-requeue_resolve:
-	cifs_dbg(FYI, "%s: next dns resolution scheduled for %lu seconds in the future\n",
-		 __func__, ttl);
-	mod_delayed_work(cifsiod_wq, &server->resolve, (ttl * HZ));
-
 	return rc;
 }
 
@@ -148,26 +136,6 @@ static void smb2_query_server_interfaces(struct work_struct *work)
 			   (SMB_INTERFACE_POLL_INTERVAL * HZ));
 }
 
-static void cifs_resolve_server(struct work_struct *work)
-{
-	int rc;
-	struct TCP_Server_Info *server = container_of(work,
-					struct TCP_Server_Info, resolve.work);
-
-	cifs_server_lock(server);
-
-	/*
-	 * Resolve the hostname again to make sure that IP address is up-to-date.
-	 */
-	rc = reconn_set_ipaddr_from_hostname(server);
-	if (rc) {
-		cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
-				__func__, rc);
-	}
-
-	cifs_server_unlock(server);
-}
-
 /*
  * Update the tcpStatus for the server.
  * This is used to signal the cifsd thread to call cifs_reconnect
@@ -925,7 +893,6 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server)
 	spin_unlock(&server->srv_lock);
 
 	cancel_delayed_work_sync(&server->echo);
-	cancel_delayed_work_sync(&server->resolve);
 
 	spin_lock(&server->srv_lock);
 	server->tcpStatus = CifsExiting;
@@ -1549,7 +1516,6 @@ cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
 		cifs_put_tcp_session(server->primary_server, from_reconnect);
 
 	cancel_delayed_work_sync(&server->echo);
-	cancel_delayed_work_sync(&server->resolve);
 
 	if (from_reconnect)
 		/*
@@ -1655,7 +1621,6 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx,
 	INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
 	INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
 	INIT_DELAYED_WORK(&tcp_ses->echo, cifs_echo_request);
-	INIT_DELAYED_WORK(&tcp_ses->resolve, cifs_resolve_server);
 	INIT_DELAYED_WORK(&tcp_ses->reconnect, smb2_reconnect_server);
 	mutex_init(&tcp_ses->reconnect_mutex);
 #ifdef CONFIG_CIFS_DFS_UPCALL
@@ -1744,12 +1709,6 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx,
 	/* queue echo request delayed work */
 	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
 
-	/* queue dns resolution delayed work */
-	cifs_dbg(FYI, "%s: next dns resolution scheduled for %d seconds in the future\n",
-		 __func__, SMB_DNS_RESOLVE_INTERVAL_DEFAULT);
-
-	queue_delayed_work(cifsiod_wq, &tcp_ses->resolve, (SMB_DNS_RESOLVE_INTERVAL_DEFAULT * HZ));
-
 	return tcp_ses;
 
 out_err_crypto_release:

fs/cifs/sess.c

@@ -480,7 +480,6 @@ cifs_ses_add_channel(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
 		 * remove this channel
 		 */
 		cancel_delayed_work_sync(&chan->server->echo);
-		cancel_delayed_work_sync(&chan->server->resolve);
 		cancel_delayed_work_sync(&chan->server->reconnect);
 
 		spin_lock(&ses->chan_lock);