fs/ceph: Use ERR_CAST

Use ERR_CAST(x) rather than ERR_PTR(PTR_ERR(x)).  The former makes more
clear what is the purpose of the operation, which otherwise looks like a
no-op.

In the case of fs/ceph/inode.c, ERR_CAST is not needed, because the type of
the returned value is the same as the type of the enclosing function.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
type T;
T x;
identifier f;
@@

T f (...) { <+...
- ERR_PTR(PTR_ERR(x))
+ x
 ...+> }

@@
expression x;
@@

- ERR_PTR(PTR_ERR(x))
+ ERR_CAST(x)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 4fd3090..a86c1d5 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -587,7 +587,7 @@
 		CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
 	req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
 	if (IS_ERR(req))
-		return ERR_PTR(PTR_ERR(req));
+		return ERR_CAST(req);
 	req->r_dentry = dget(dentry);
 	req->r_num_caps = 2;
 	/* we only need inode linkage */
diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index 1744764..4480cb1 100644
--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -133,7 +133,7 @@
 		req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPHASH,
 					       USE_ANY_MDS);
 		if (IS_ERR(req))
-			return ERR_PTR(PTR_ERR(req));
+			return ERR_CAST(req);
 
 		req->r_ino1 = vino;
 		req->r_ino2.ino = cfh->parent_ino;
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 0611ec3..f06f902 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -230,7 +230,7 @@
 	/* do the open */
 	req = prepare_open_request(dir->i_sb, flags, mode);
 	if (IS_ERR(req))
-		return ERR_PTR(PTR_ERR(req));
+		return ERR_CAST(req);
 	req->r_dentry = dget(dentry);
 	req->r_num_caps = 2;
 	if (flags & O_CREAT) {
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index a81b8b6..226f5a5 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -69,7 +69,7 @@
 
 	BUG_ON(!S_ISDIR(parent->i_mode));
 	if (IS_ERR(inode))
-		return ERR_PTR(PTR_ERR(inode));
+		return inode;
 	inode->i_mode = parent->i_mode;
 	inode->i_uid = parent->i_uid;
 	inode->i_gid = parent->i_gid;
diff --git a/fs/ceph/osdmap.c b/fs/ceph/osdmap.c
index cfdd8f4..ddc656f 100644
--- a/fs/ceph/osdmap.c
+++ b/fs/ceph/osdmap.c
@@ -706,7 +706,7 @@
 		     len, *p, end);
 		newcrush = crush_decode(*p, min(*p+len, end));
 		if (IS_ERR(newcrush))
-			return ERR_PTR(PTR_ERR(newcrush));
+			return ERR_CAST(newcrush);
 	}
 
 	/* new flags? */
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index bac1389..9b46bb9 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -738,7 +738,7 @@
 	dout("open_root_inode opening '%s'\n", path);
 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
 	if (IS_ERR(req))
-		return ERR_PTR(PTR_ERR(req));
+		return ERR_CAST(req);
 	req->r_path1 = kstrdup(path, GFP_NOFS);
 	req->r_ino1.ino = CEPH_INO_ROOT;
 	req->r_ino1.snap = CEPH_NOSNAP;