Commit 12b0004d authored by Cong Wang's avatar Cong Wang Committed by David S. Miller
Browse files

net: adjust skb_gso_segment() for calling in rx path 



skb_gso_segment() is almost always called in tx path,
except for openvswitch. It calls this function when
it receives the packet and tries to queue it to user-space.
In this special case, the ->ip_summed check inside
skb_gso_segment() is no longer true, as ->ip_summed value
has different meanings on rx path.

This patch adjusts skb_gso_segment() so that we can at least
avoid such warnings on checksum.

Cc: Jesse Gross <jesse@nicira.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: default avatarCong Wang <amwang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 25060d8f

include/linux/netdevice.h

+9 −2
Original line number Diff line number Diff line
@@ -2662,8 +2662,15 @@ extern int netdev_master_upper_dev_link(struct net_device *dev, 
extern void netdev_upper_dev_unlink(struct net_device *dev,

				    struct net_device *upper_dev);

extern int skb_checksum_help(struct sk_buff *skb);

extern struct sk_buff *skb_gso_segment(struct sk_buff *skb,

	netdev_features_t features);

extern struct sk_buff *__skb_gso_segment(struct sk_buff *skb,

	netdev_features_t features, bool tx_path);



static inline

struct sk_buff *skb_gso_segment(struct sk_buff *skb, netdev_features_t features)

{

	return __skb_gso_segment(skb, features, true);

}



#ifdef CONFIG_BUG

extern void netdev_rx_csum_fault(struct net_device *dev);

#else

net/core/dev.c

+16 −5
Original line number Diff line number Diff line
@@ -2327,18 +2327,29 @@ out: 
}

EXPORT_SYMBOL(skb_checksum_help);



/* openvswitch calls this on rx path, so we need a different check.

 */

static inline bool skb_needs_check(struct sk_buff *skb, bool tx_path)

{

	if (tx_path)

		return skb->ip_summed != CHECKSUM_PARTIAL;

	else

		return skb->ip_summed == CHECKSUM_NONE;

}



/**

 *	skb_gso_segment - Perform segmentation on skb.

 *	__skb_gso_segment - Perform segmentation on skb.

 *	@skb: buffer to segment

 *	@features: features for the output path (see dev->features)

 *	@tx_path: whether it is called in TX path

 *

 *	This function segments the given skb and returns a list of segments.

 *

 *	It may return NULL if the skb requires no segmentation.  This is

 *	only possible when GSO is used for verifying header integrity.

 */

struct sk_buff *skb_gso_segment(struct sk_buff *skb,

	netdev_features_t features)

struct sk_buff *__skb_gso_segment(struct sk_buff *skb,

				  netdev_features_t features, bool tx_path)

{

	struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);

	struct packet_offload *ptype;
@@ -2361,7 +2372,7 @@ struct sk_buff *skb_gso_segment(struct sk_buff *skb, 
	skb->mac_len = skb->network_header - skb->mac_header;

	__skb_pull(skb, skb->mac_len);



	if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {

	if (unlikely(skb_needs_check(skb, tx_path))) {

		skb_warn_bad_offload(skb);



		if (skb_header_cloned(skb) &&
@@ -2390,7 +2401,7 @@ struct sk_buff *skb_gso_segment(struct sk_buff *skb, 


	return segs;

}

EXPORT_SYMBOL(skb_gso_segment);

EXPORT_SYMBOL(__skb_gso_segment);



/* Take action when hardware reception checksum errors are detected. */

#ifdef CONFIG_BUG

net/openvswitch/datapath.c

+1 −1
Original line number Diff line number Diff line
@@ -301,7 +301,7 @@ static int queue_gso_packets(struct net *net, int dp_ifindex, 
	struct sk_buff *segs, *nskb;

	int err;



	segs = skb_gso_segment(skb, NETIF_F_SG | NETIF_F_HW_CSUM);

	segs = __skb_gso_segment(skb, NETIF_F_SG | NETIF_F_HW_CSUM, false);

	if (IS_ERR(segs))

		return PTR_ERR(segs);

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