fs/nfs4callback: replace schedule_timeout() with ssleep()

diff -puN fs/nfsd/nfs4callback.c~ssleep-fs_nfsd_nfs4callback fs/nfsd/nfs4callback.c
@@ -38,6 +38,7 @@
 #include <linux/list.h>
 #include <linux/inet.h>
 #include <linux/errno.h>
+#include <linux/delay.h>
 #include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/svc.h>
 #include <linux/sunrpc/clnt.h>

@@ -531,8 +532,7 @@ out:
 retry:
 	atomic_inc(&dp->dl_recall_cnt);
 	/* sleep 2 seconds before retrying recall */
-	set_current_state(TASK_UNINTERRUPTIBLE);
-	schedule_timeout(2*HZ);
+	ssleep(2);
 	status = nfsd4_cb_recall(dp);
 	dprintk("NFSD: nfs4_cb_recall_done: retry status: %d  dp %p dl_flock %p\n",status,dp, dp->dl_flock);
 }