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Commit 63d75463 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

net: pktgen: fix pkt_size 



The commit 879c7220 ("net: pktgen: Observe needed_headroom
of the device") increased the 'pkt_overhead' field value by
LL_RESERVED_SPACE.
As a side effect the generated packet size, computed as:

	/* Eth + IPh + UDPh + mpls */
	datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 -
		  pkt_dev->pkt_overhead;

is decreased by the same value.
The above changed slightly the behavior of existing pktgen users,
and made the procfs interface somewhat inconsistent.
Fix it by restoring the previous pkt_overhead value and using
LL_RESERVED_SPACE as extralen in skb allocation.
Also, change pktgen_alloc_skb() to only partially reserve
the headroom to allow the caller to prefetch from ll header
start.

v1 -> v2:
 - fixed some typos in the comments

Fixes: 879c7220 ("net: pktgen: Observe needed_headroom of the device")
Suggested-by: default avatarBen Greear <greearb@candelatech.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b82d44d7

net/core/pktgen.c

+10 −11
Original line number Diff line number Diff line
@@ -2286,7 +2286,7 @@ static void spin(struct pktgen_dev *pkt_dev, ktime_t spin_until) 


static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev)

{

	pkt_dev->pkt_overhead = LL_RESERVED_SPACE(pkt_dev->odev);

	pkt_dev->pkt_overhead = 0;

	pkt_dev->pkt_overhead += pkt_dev->nr_labels*sizeof(u32);

	pkt_dev->pkt_overhead += VLAN_TAG_SIZE(pkt_dev);

	pkt_dev->pkt_overhead += SVLAN_TAG_SIZE(pkt_dev);
@@ -2777,13 +2777,13 @@ static void pktgen_finalize_skb(struct pktgen_dev *pkt_dev, struct sk_buff *skb, 
}



static struct sk_buff *pktgen_alloc_skb(struct net_device *dev,

					struct pktgen_dev *pkt_dev,

					unsigned int extralen)

					struct pktgen_dev *pkt_dev)

{

	unsigned int extralen = LL_RESERVED_SPACE(dev);

	struct sk_buff *skb = NULL;

	unsigned int size = pkt_dev->cur_pkt_size + 64 + extralen +

			    pkt_dev->pkt_overhead;

	unsigned int size;



	size = pkt_dev->cur_pkt_size + 64 + extralen + pkt_dev->pkt_overhead;

	if (pkt_dev->flags & F_NODE) {

		int node = pkt_dev->node >= 0 ? pkt_dev->node : numa_node_id();
@@ -2796,8 +2796,9 @@ static struct sk_buff *pktgen_alloc_skb(struct net_device *dev, 
		 skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT);

	}



	/* the caller pre-fetches from skb->data and reserves for the mac hdr */

	if (likely(skb))

		skb_reserve(skb, LL_RESERVED_SPACE(dev));

		skb_reserve(skb, extralen - 16);



	return skb;

}
@@ -2830,16 +2831,14 @@ static struct sk_buff *fill_packet_ipv4(struct net_device *odev, 
	mod_cur_headers(pkt_dev);

	queue_map = pkt_dev->cur_queue_map;



	datalen = (odev->hard_header_len + 16) & ~0xf;



	skb = pktgen_alloc_skb(odev, pkt_dev, datalen);

	skb = pktgen_alloc_skb(odev, pkt_dev);

	if (!skb) {

		sprintf(pkt_dev->result, "No memory");

		return NULL;

	}



	prefetchw(skb->data);

	skb_reserve(skb, datalen);

	skb_reserve(skb, 16);



	/*  Reserve for ethernet and IP header  */

	eth = (__u8 *) skb_push(skb, 14);
@@ -2959,7 +2958,7 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev, 
	mod_cur_headers(pkt_dev);

	queue_map = pkt_dev->cur_queue_map;



	skb = pktgen_alloc_skb(odev, pkt_dev, 16);

	skb = pktgen_alloc_skb(odev, pkt_dev);

	if (!skb) {

		sprintf(pkt_dev->result, "No memory");

		return NULL;