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Commit 87151b86 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: allow pskb_expand_head() to get maximum tailroom 



Marc Merlin reported many order-1 allocations failures in TX path on its
wireless setup, that dont make any sense with MTU=1500 network, and non
SG capable hardware.

Turns out part of the problem comes from pskb_expand_head() not using
ksize() to get exact head size given by kmalloc(). Doing the same thing
than __alloc_skb() allows more tailroom in skb and can prevent future
reallocations.

As a bonus, struct skb_shared_info becomes cache line aligned.

Reported-by: default avatarMarc MERLIN <marc@merlins.org>
Tested-by: default avatarMarc MERLIN <marc@merlins.org>
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 996304bb

net/core/skbuff.c

+3 −1
Original line number Diff line number Diff line
@@ -952,9 +952,11 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, 
		goto adjust_others;

	}



	data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);

	data = kmalloc(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),

		       gfp_mask);

	if (!data)

		goto nodata;

	size = SKB_WITH_OVERHEAD(ksize(data));



	/* Copy only real data... and, alas, header. This should be

	 * optimized for the cases when header is void.