cifs: remove unnecessary locking of chan_lock while freeing session

In cifs_put_smb_ses, when we're freeing the last ref count to
the session, we need to free up each channel. At this point,
it is unnecessary to take chan_lock, since we have the last
reference to the ses.

Picking up this lock also introduced a deadlock because it calls
cifs_put_tcp_ses, which locks cifs_tcp_ses_lock.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: sprasad-microsoft

fs/cifs/connect.c

@@ -1918,7 +1918,6 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
 	list_del_init(&ses->smb_ses_list);
 	spin_unlock(&cifs_tcp_ses_lock);
 
-	spin_lock(&ses->chan_lock);
 	chan_count = ses->chan_count;
 
 	/* close any extra channels */
@@ -1934,7 +1933,6 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
 			ses->chans[i].server = NULL;
 		}
 	}
-	spin_unlock(&ses->chan_lock);
 
 	sesInfoFree(ses);
 	cifs_put_tcp_session(server, 0);