[PATCH] aoe 12/12: send outgoing packets in order

I can't use list.h, since sk_buff doesn't have a list_head but instead
has two struct sk_buff pointers, and I want to avoid any extra memory
allocation.

send outgoing packets in order
Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/block/aoe/aoe.h

@@ -131,7 +131,8 @@ struct aoedev {
 	struct timer_list timer;
 	spinlock_t lock;
 	struct net_device *ifp;	/* interface ed is attached to */
-	struct sk_buff *skblist;/* packets needing to be sent */
+	struct sk_buff *sendq_hd; /* packets needing to be sent, list head */
+	struct sk_buff *sendq_tl;
 	mempool_t *bufpool;	/* for deadlock-free Buf allocation */
 	struct list_head bufq;	/* queue of bios to work on */
 	struct buf *inprocess;	/* the one we're currently working on */

drivers/block/aoe/aoeblk.c

@@ -147,8 +147,8 @@ aoeblk_make_request(request_queue_t *q, struct bio *bio)
 	list_add_tail(&buf->bufs, &d->bufq);
 	aoecmd_work(d);
 
-	sl = d->skblist;
-	d->skblist = NULL;
+	sl = d->sendq_hd;
+	d->sendq_hd = d->sendq_tl = NULL;
 
 	spin_unlock_irqrestore(&d->lock, flags);
 

drivers/block/aoe/aoecmd.c

@@ -178,8 +178,12 @@ aoecmd_ata_rw(struct aoedev *d, struct frame *f)
 
 	skb = skb_prepare(d, f);
 	if (skb) {
-		skb->next = d->skblist;
-		d->skblist = skb;
+		skb->next = NULL;
+		if (d->sendq_hd)
+			d->sendq_tl->next = skb;
+		else
+			d->sendq_hd = skb;
+		d->sendq_tl = skb;
 	}
 }
 
@@ -227,8 +231,12 @@ rexmit(struct aoedev *d, struct frame *f)
 
 	skb = skb_prepare(d, f);
 	if (skb) {
-		skb->next = d->skblist;
-		d->skblist = skb;
+		skb->next = NULL;
+		if (d->sendq_hd)
+			d->sendq_tl->next = skb;
+		else
+			d->sendq_hd = skb;
+		d->sendq_tl = skb;
 	}
 }
 
@@ -280,8 +288,8 @@ tdie:		spin_unlock_irqrestore(&d->lock, flags);
 		}
 	}
 
-	sl = d->skblist;
-	d->skblist = NULL;
+	sl = d->sendq_hd;
+	d->sendq_hd = d->sendq_tl = NULL;
 	if (sl) {
 		n = d->rttavg <<= 1;
 		if (n > MAXTIMER)
@@ -481,8 +489,8 @@ aoecmd_ata_rsp(struct sk_buff *skb)
 
 	aoecmd_work(d);
 
-	sl = d->skblist;
-	d->skblist = NULL;
+	sl = d->sendq_hd;
+	d->sendq_hd = d->sendq_tl = NULL;
 
 	spin_unlock_irqrestore(&d->lock, flags);
 
@@ -531,7 +539,7 @@ aoecmd_cfg(ushort aoemajor, unsigned char aoeminor)
  
 /*
  * Since we only call this in one place (and it only prepares one frame)
- * we just return the skb.  Usually we'd chain it up to the d->skblist.
+ * we just return the skb.  Usually we'd chain it up to the aoedev sendq.
  */
 static struct sk_buff *
 aoecmd_ata_id(struct aoedev *d)