cifs: Fix oops due to uncleared server->smbd_conn in reconnect

stable inclusion
from stable-v5.10.166
commit e037baee16e0b9ace7e730888fcae9cec11daff2
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7TH9O

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e037baee16e0b9ace7e730888fcae9cec11daff2

--------------------------------

commit b7ab9161 upstream.

In smbd_destroy(), clear the server->smbd_conn pointer after freeing the
smbd_connection struct that it points to so that reconnection doesn't get
confused.

Fixes: 8ef130f9 ("CIFS: SMBD: Implement function to destroy a SMB Direct connection")
Cc: stable@vger.kernel.org
Reviewed-by: NPaulo Alcantara (SUSE) <pc@cjr.nz>
Acked-by: NTom Talpey <tom@talpey.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: Long Li <longli@microsoft.com>
Cc: Pavel Shilovsky <piastryyy@gmail.com>
Cc: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Nsanglipeng <sanglipeng1@jd.com>

fs/cifs/smbdirect.c

@@ -1394,6 +1394,7 @@ void smbd_destroy(struct TCP_Server_Info *server)
 	destroy_workqueue(info->workqueue);
 	log_rdma_event(INFO,  "rdma session destroyed\n");
 	kfree(info);
+	server->smbd_conn = NULL;
 }
 
 /*