ceph: define ceph_encode_8_safe()

It's kind of a silly macro, but ceph_encode_8_safe() is the only one
missing from an otherwise pretty complete set.  It's not used, but
neither are a couple of the others in this set.

While in there, insert some whitespace to tidy up the alignment of
the line-terminating backslashes in some of the macro definitions.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NDan Mick <dan.mick@inktank.com>

include/linux/ceph/decode.h

@@ -99,8 +99,8 @@ static inline int ceph_has_room(void **p, void *end, size_t n)
  *
  * There are two possible failures:
  *   - converting the string would require accessing memory at or
- *     beyond the "end" pointer provided (-E
- *   - memory could not be allocated for the result
+ *     beyond the "end" pointer provided (-ERANGE)
+ *   - memory could not be allocated for the result (-ENOMEM)
  */
 static inline char *ceph_extract_encoded_string(void **p, void *end,
 						size_t *lenp, gfp_t gfp)
@@ -238,6 +238,11 @@ static inline void ceph_encode_string(void **p, void *end,
 		ceph_encode_need(p, end, sizeof(u16), bad);	\
 		ceph_encode_16(p, v);				\
 	} while (0)
+#define ceph_encode_8_safe(p, end, v, bad)			\
+	do {							\
+		ceph_encode_need(p, end, sizeof(u8), bad);	\
+		ceph_encode_8(p, v);				\
+	} while (0)
 
 #define ceph_encode_copy_safe(p, end, pv, n, bad)		\
 	do {							\