9p: Reduce object size with CONFIG_NET_9P_DEBUG

Reduce object size by deduplicating formats.

Use vsprintf extension %pV.
Rename P9_DPRINTK uses to p9_debug, align arguments.
Add function for _p9_debug and macro to add __func__.
Add missing "\n"s to p9_debug uses.
Remove embedded function names as p9_debug adds it.
Remove P9_EPRINTK macro and convert use to pr_<level>.
Add and use pr_fmt and pr_<level>.

$ size fs/9p/built-in.o*
   text	   data	    bss	    dec	    hex	filename
  62133	    984	  16000	  79117	  1350d	fs/9p/built-in.o.new
  67342	    984	  16928	  85254	  14d06	fs/9p/built-in.o.old
$ size net/9p/built-in.o*
   text	   data	    bss	    dec	    hex	filename
  88792	   4148	  22024	 114964	  1c114	net/9p/built-in.o.new
  94072	   4148	  23232	 121452	  1da6c	net/9p/built-in.o.old

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 598fff1..ff911e7 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -140,7 +140,7 @@
 	int reclen = 0;
 	struct p9_rdir *rdir;
 
-	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
+	p9_debug(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
 	fid = filp->private_data;
 
 	buflen = fid->clnt->msize - P9_IOHDRSZ;
@@ -168,7 +168,7 @@
 			err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
 					  rdir->tail - rdir->head, &st);
 			if (err) {
-				P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
+				p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
 				err = -EIO;
 				p9stat_free(&st);
 				goto unlock_and_exit;
@@ -213,7 +213,7 @@
 	struct p9_dirent curdirent;
 	u64 oldoffset = 0;
 
-	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
+	p9_debug(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
 	fid = filp->private_data;
 
 	buflen = fid->clnt->msize - P9_READDIRHDRSZ;
@@ -244,7 +244,7 @@
 					    rdir->tail - rdir->head,
 					    &curdirent);
 			if (err < 0) {
-				P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
+				p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
 				err = -EIO;
 				goto unlock_and_exit;
 			}
@@ -290,9 +290,8 @@
 	struct p9_fid *fid;
 
 	fid = filp->private_data;
-	P9_DPRINTK(P9_DEBUG_VFS,
-			"v9fs_dir_release: inode: %p filp: %p fid: %d\n",
-			inode, filp, fid ? fid->fid : -1);
+	p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
+		 inode, filp, fid ? fid->fid : -1);
 	if (fid)
 		p9_client_clunk(fid);
 	return 0;