knfsd: nfsd4: fix enc_stateid_sz for nfsd callbacks

enc_stateid_sz should be given in u32 words units, not bytes, so we were
overestimating the buffer space needed here.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nfsd/nfs4callback.c

@@ -75,7 +75,7 @@ enum nfs_cb_opnum4 {
 #define op_enc_sz			1
 #define op_dec_sz			2
 #define enc_nfs4_fh_sz			(1 + (NFS4_FHSIZE >> 2))
-#define enc_stateid_sz			16
+#define enc_stateid_sz			(NFS4_STATEID_SIZE >> 2)
 #define NFS4_enc_cb_recall_sz		(cb_compound_enc_hdr_sz +       \
 					1 + enc_stateid_sz +            \
 					enc_nfs4_fh_sz)