From: David S. Miller <davem@davemloft.net>
Date: Tue, 2 Sep 2014 00:40:01 +0000 (-0700)
Subject: Merge branch 'xmit_list'
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=53fda7f7f9e;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

Merge branch 'xmit_list'

David Miller says:

====================
net: Make dev_hard_start_xmit() work fundamentally on lists

After this patch set, dev_hard_start_xmit() will work fundemantally on
any and all SKB lists.

This opens the path for a clean implementation of pulling multiple
packets out during qdisc_restart(), and then passing that blob in one
shot to dev_hard_start_xmit().

There were two main architectural blockers to this:

1) The GSO handling, we kept the original GSO head SKB around simply
   because dev_hard_start_xmit() had no way to communicate to the
   caller how far into the segmented list it was able to go.  Now it
   can, so the head GSO can be liberated immediately.

   All of the special GSO head SKB destructor et al. handling goes
   away too.

2) Validate of VLAN, CSUM, and segmentation characteristics was being
   performed inside of dev_hard_start_xmit().  If want to truly batch,
   we have to let the higher levels to this.  In particular, this is
   now dequeue_skb()'s job.

And with those two issues out of the way, it should now be trivial to
build experiments on top of this patch set, all of the framework
should be there now.  You could do something as simple as:

	skb = q->dequeue(q);
	if (skb)
		skb = validate_xmit_skb(skb, qdisc_dev(q));
	if (skb) {
		struct sk_buff *new, *head = skb;
		int limit = 5;

		do {
			new = q->dequeue(q);
			if (new)
				new = validate_xmit_skb(new, qdisc_dev(q));
			if (new) {
				skb->next = new;
				skb = new;
			}
		} while (new && --limit);
		skb = head;
	}

inside of the else branch of dequeue_skb().

Signed-off-by: David S. Miller <davem@davemloft.net>
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53fda7f7f9e88fa9015b2cdabebfaf5477a28241