libceph: define ceph_decode_pgid() only once

There are two basically identical definitions of __decode_pgid()
in libceph, one in "net/ceph/osdmap.c" and the other in
"net/ceph/osd_client.c".  Get rid of both, and instead define
a single inline version in "include/linux/ceph/osdmap.h".

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

include/linux/ceph/osdmap.h

@@ -3,6 +3,7 @@
 
 #include <linux/rbtree.h>
 #include <linux/ceph/types.h>
+#include <linux/ceph/decode.h>
 #include <linux/ceph/ceph_fs.h>
 #include <linux/crush/crush.h>
 
@@ -119,6 +120,29 @@ static inline struct ceph_entity_addr *ceph_osd_addr(struct ceph_osdmap *map,
 	return &map->osd_addr[osd];
 }
 
+static inline int ceph_decode_pgid(void **p, void *end, struct ceph_pg *pgid)
+{
+	__u8 version;
+
+	if (!ceph_has_room(p, end, 1 + 8 + 4 + 4)) {
+		pr_warning("incomplete pg encoding");
+
+		return -EINVAL;
+	}
+	version = ceph_decode_8(p);
+	if (version > 1) {
+		pr_warning("do not understand pg encoding %d > 1",
+			(int)version);
+		return -EINVAL;
+	}
+
+	pgid->pool = ceph_decode_64(p);
+	pgid->seed = ceph_decode_32(p);
+	*p += 4;	/* skip deprecated preferred value */
+
+	return 0;
+}
+
 extern struct ceph_osdmap *osdmap_decode(void **p, void *end);
 extern struct ceph_osdmap *osdmap_apply_incremental(void **p, void *end,
 					    struct ceph_osdmap *map,

net/ceph/osd_client.c

@@ -1268,26 +1268,6 @@ static void complete_request(struct ceph_osd_request *req)
 	complete_all(&req->r_safe_completion);  /* fsync waiter */
 }
 
-static int __decode_pgid(void **p, void *end, struct ceph_pg *pgid)
-{
-	__u8 v;
-
-	ceph_decode_need(p, end, 1 + 8 + 4 + 4, bad);
-	v = ceph_decode_8(p);
-	if (v > 1) {
-		pr_warning("do not understand pg encoding %d > 1", v);
-		return -EINVAL;
-	}
-	pgid->pool = ceph_decode_64(p);
-	pgid->seed = ceph_decode_32(p);
-	*p += 4;
-	return 0;
-
-bad:
-	pr_warning("incomplete pg encoding");
-	return -EINVAL;
-}
-
 /*
  * handle osd op reply.  either call the callback if it is specified,
  * or do the completion to wake up the waiting thread.
@@ -1321,7 +1301,7 @@ static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg,
 	ceph_decode_need(&p, end, object_len, bad);
 	p += object_len;
 
-	err = __decode_pgid(&p, end, &pg);
+	err = ceph_decode_pgid(&p, end, &pg);
 	if (err)
 		goto bad;
 

net/ceph/osdmap.c

@@ -654,24 +654,6 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, int max)
 	return 0;
 }
 
-static int __decode_pgid(void **p, void *end, struct ceph_pg *pg)
-{
-	u8 v;
-
-	ceph_decode_need(p, end, 1+8+4+4, bad);
-	v = ceph_decode_8(p);
-	if (v != 1)
-		goto bad;
-	pg->pool = ceph_decode_64(p);
-	pg->seed = ceph_decode_32(p);
-	*p += 4; /* skip preferred */
-	return 0;
-
-bad:
-	dout("error decoding pgid\n");
-	return -EINVAL;
-}
-
 /*
  * decode a full map.
  */
@@ -765,7 +747,7 @@ struct ceph_osdmap *osdmap_decode(void **p, void *end)
 		struct ceph_pg pgid;
 		struct ceph_pg_mapping *pg;
 
-		err = __decode_pgid(p, end, &pgid);
+		err = ceph_decode_pgid(p, end, &pgid);
 		if (err)
 			goto bad;
 		ceph_decode_need(p, end, sizeof(u32), bad);
@@ -983,7 +965,7 @@ struct ceph_osdmap *osdmap_apply_incremental(void **p, void *end,
 		struct ceph_pg pgid;
 		u32 pglen;
 
-		err = __decode_pgid(p, end, &pgid);
+		err = ceph_decode_pgid(p, end, &pgid);
 		if (err)
 			goto bad;
 		ceph_decode_need(p, end, sizeof(u32), bad);