nfsd: fix clp->cl_revoked list deletion causing softlock in nfsd

commit 2d4a532d385f ("nfsd: ensure that clp->cl_revoked list is
protected by clp->cl_lock") removed the use of the reaplist to
clean out clp->cl_revoked. It failed to change list_entry() to
walk clp->cl_revoked.next instead of reaplist.next

Fixes: 2d4a532d385f ("nfsd: ensure that clp->cl_revoked list is protected by clp->cl_lock")
Cc: stable@vger.kernel.org
Reported-by: Eric Meddaugh <etmsys@rit.edu>
Tested-by: Eric Meddaugh <etmsys@rit.edu>
Signed-off-by: Andrew Elble <aweits@rit.edu>
Reviewed-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -1638,7 +1638,7 @@ __destroy_client(struct nfs4_client *clp)
 		nfs4_put_stid(&dp->dl_stid);
 	}
 	while (!list_empty(&clp->cl_revoked)) {
-		dp = list_entry(reaplist.next, struct nfs4_delegation, dl_recall_lru);
+		dp = list_entry(clp->cl_revoked.next, struct nfs4_delegation, dl_recall_lru);
 		list_del_init(&dp->dl_recall_lru);
 		nfs4_put_stid(&dp->dl_stid);
 	}