cifs: do not poll server interfaces too regularly

commit 072a28c8907c841f7d4b56c78bce46d3ee211e73 upstream.

We have the server interface list hanging off the tcon
structure today for reasons unknown. So each tcon which is
connected to a file server can query them separately,
which is really unnecessary. To avoid this, in the query
function, we will check the time of last update of the
interface list, and avoid querying the server if it is
within a certain range.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 7cb26faf1b504b3cc0c12d0fc6bf111ebbfe5eb4..30ef1aebcbe49fe5ea537632c71c6b9501cfd55c 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -530,6 +530,14 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
        p = buf;
 
        spin_lock(&ses->iface_lock);
+       /* do not query too frequently, this time with lock held */
+       if (ses->iface_last_update &&
+           time_before(jiffies, ses->iface_last_update +
+                       (SMB_INTERFACE_POLL_INTERVAL * HZ))) {
+               spin_unlock(&ses->iface_lock);
+               return 0;
+       }
+
        /*
         * Go through iface_list and do kref_put to remove
         * any unused ifaces. ifaces in use will be removed
@@ -696,6 +704,12 @@ SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon, bool in_
        struct network_interface_info_ioctl_rsp *out_buf = NULL;
        struct cifs_ses *ses = tcon->ses;
 
+       /* do not query too frequently */
+       if (ses->iface_last_update &&
+           time_before(jiffies, ses->iface_last_update +
+                       (SMB_INTERFACE_POLL_INTERVAL * HZ)))
+               return 0;
+
        rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                        FSCTL_QUERY_NETWORK_INTERFACE_INFO,
                        NULL /* no data input */, 0 /* no data input */,