Commit 715dc1f3 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: Fix truesize accounting in skb_gro_receive() 



GRO is very optimistic in skb truesize estimates, only taking into
account the used part of fragments.

Be conservative, and use more precise computation, so that bloated GRO
skbs can be collapsed eventually.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent af94bf6d

net/core/skbuff.c

+8 −3
Original line number Diff line number Diff line
@@ -2871,6 +2871,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) 
	unsigned int len = skb_gro_len(skb);

	unsigned int offset = skb_gro_offset(skb);

	unsigned int headlen = skb_headlen(skb);

	unsigned int delta_truesize;



	if (p->len + len >= 65536)

		return -E2BIG;
@@ -2900,11 +2901,14 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) 
		frag->page_offset += offset;

		skb_frag_size_sub(frag, offset);



		/* all fragments truesize : remove (head size + sk_buff) */

		delta_truesize = skb->truesize - SKB_TRUESIZE(skb_end_pointer(skb) - skb->head);



		skb->truesize -= skb->data_len;

		skb->len -= skb->data_len;

		skb->data_len = 0;



		NAPI_GRO_CB(skb)->free = 1;

		NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;

		goto done;

	} else if (skb->head_frag) {

		int nr_frags = pinfo->nr_frags;
@@ -2929,6 +2933,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) 
		memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);

		/* We dont need to clear skbinfo->nr_frags here */



		delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));

		NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;

		goto done;

	} else if (skb_gro_len(p) != pinfo->gso_size)
@@ -2971,7 +2976,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) 
	p = nskb;



merge:

	p->truesize += skb->truesize - len;

	delta_truesize = skb->truesize;

	if (offset > headlen) {

		unsigned int eat = offset - headlen;
@@ -2991,7 +2996,7 @@ merge: 
done:

	NAPI_GRO_CB(p)->count++;

	p->data_len += len;

	p->truesize += len;

	p->truesize += delta_truesize;

	p->len += len;



	NAPI_GRO_CB(skb)->same_flow = 1;

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