From: lxlenovostar@gmail.com (lx)
To: kernelnewbies@lists.kernelnewbies.org
Subject: hi , question function of net_rx(struct net_device *dev)
Date: Fri, 18 Jul 2014 17:04:38 +0800 [thread overview]
Message-ID: <53C8E326.5080805@gmail.com> (raw)
hi :
the source code of net_rx(struct net_device *dev) is:
http://lxr.oss.org.cn/source/drivers/net/ethernet/cirrus/cs89x0.c#L670
I can't understand codes about malloc buffer.
##########################################
684 /* Malloc up new buffer. */
685 skb = netdev_alloc_skb(dev, length + 2);
686 if (skb == NULL) {
687 dev->stats.rx_dropped++;
688 return;
689 }
690 skb_reserve(skb, 2); /* longword align L3 header */
##########################################
How to explain 'length + 2' in line of 685? Why add 2 ?
Thank you.
next reply other threads:[~2014-07-18 9:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-18 9:04 lx [this message]
2014-07-18 10:05 ` hi , question function of net_rx(struct net_device *dev) Denis Kirjanov
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