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/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 32aa983..330421e 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -26,6 +26,8 @@
  *
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/in.h>
 #include <linux/module.h>
 #include <linux/net.h>
@@ -145,7 +147,7 @@
 	struct p9_req_t *req;
 	unsigned long flags;
 
-	P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n");
+	p9_debug(P9_DEBUG_TRANS, ": request done\n");
 
 	while (1) {
 		spin_lock_irqsave(&chan->lock, flags);
@@ -158,8 +160,8 @@
 		spin_unlock_irqrestore(&chan->lock, flags);
 		/* Wakeup if anyone waiting for VirtIO ring space. */
 		wake_up(chan->vc_wq);
-		P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc);
-		P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag);
+		p9_debug(P9_DEBUG_TRANS, ": rc %p\n", rc);
+		p9_debug(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag);
 		req = p9_tag_lookup(chan->client, rc->tag);
 		req->status = REQ_STATUS_RCVD;
 		p9_client_cb(chan->client, req);
@@ -257,7 +259,7 @@
 	unsigned long flags;
 	struct virtio_chan *chan = client->trans;
 
-	P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n");
+	p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n");
 
 	req->status = REQ_STATUS_SENT;
 req_retry:
@@ -280,20 +282,19 @@
 			if (err  == -ERESTARTSYS)
 				return err;
 
-			P9_DPRINTK(P9_DEBUG_TRANS, "9p:Retry virtio request\n");
+			p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
 			goto req_retry;
 		} else {
 			spin_unlock_irqrestore(&chan->lock, flags);
-			P9_DPRINTK(P9_DEBUG_TRANS,
-					"9p debug: "
-					"virtio rpc add_buf returned failure");
+			p9_debug(P9_DEBUG_TRANS,
+				 "virtio rpc add_buf returned failure\n");
 			return -EIO;
 		}
 	}
 	virtqueue_kick(chan->vq);
 	spin_unlock_irqrestore(&chan->lock, flags);
 
-	P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n");
+	p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
 	return 0;
 }
 
@@ -354,7 +355,7 @@
 	struct page **in_pages = NULL, **out_pages = NULL;
 	struct virtio_chan *chan = client->trans;
 
-	P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n");
+	p9_debug(P9_DEBUG_TRANS, "virtio request\n");
 
 	if (uodata) {
 		out_nr_pages = p9_nr_pages(uodata, outlen);
@@ -423,20 +424,19 @@
 			if (err  == -ERESTARTSYS)
 				goto err_out;
 
-			P9_DPRINTK(P9_DEBUG_TRANS, "9p:Retry virtio request\n");
+			p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
 			goto req_retry_pinned;
 		} else {
 			spin_unlock_irqrestore(&chan->lock, flags);
-			P9_DPRINTK(P9_DEBUG_TRANS,
-				   "9p debug: "
-				   "virtio rpc add_buf returned failure");
+			p9_debug(P9_DEBUG_TRANS,
+				 "virtio rpc add_buf returned failure\n");
 			err = -EIO;
 			goto err_out;
 		}
 	}
 	virtqueue_kick(chan->vq);
 	spin_unlock_irqrestore(&chan->lock, flags);
-	P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n");
+	p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
 	err = wait_event_interruptible(*req->wq,
 				       req->status >= REQ_STATUS_RCVD);
 	/*
@@ -491,7 +491,7 @@
 
 	chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
 	if (!chan) {
-		printk(KERN_ERR "9p: Failed to allocate virtio 9P channel\n");
+		pr_err("Failed to allocate virtio 9P channel\n");
 		err = -ENOMEM;
 		goto fail;
 	}
@@ -592,7 +592,7 @@
 	mutex_unlock(&virtio_9p_lock);
 
 	if (!found) {
-		printk(KERN_ERR "9p: no channels available\n");
+		pr_err("no channels available\n");
 		return ret;
 	}