diff options
| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2007-04-20 05:29:13 +0200 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-04-26 07:26:28 +0200 |
| commit | 27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26 (patch) | |
| tree | 5a267e40f9b94014be38dad5de0a52b6628834e0 /drivers/media | |
| parent | [VLAN] vlan_dev: Use skb_reset_network_header(). (diff) | |
| download | linux-27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26.tar.xz linux-27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26.zip | |
[SK_BUFF]: Convert skb->tail to sk_buff_data_t
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)
Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/dvb/dvb-core/dvb_net.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/media/dvb/dvb-core/dvb_net.c b/drivers/media/dvb/dvb-core/dvb_net.c index c6b004182d91..9de177a5b9f1 100644 --- a/drivers/media/dvb/dvb-core/dvb_net.c +++ b/drivers/media/dvb/dvb-core/dvb_net.c @@ -600,6 +600,7 @@ static void dvb_net_ule( struct net_device *dev, const u8 *buf, size_t buf_len ) /* Check CRC32, we've got it in our skb already. */ unsigned short ulen = htons(priv->ule_sndu_len); unsigned short utype = htons(priv->ule_sndu_type); + const u8 *tail; struct kvec iov[3] = { { &ulen, sizeof ulen }, { &utype, sizeof utype }, @@ -613,10 +614,11 @@ static void dvb_net_ule( struct net_device *dev, const u8 *buf, size_t buf_len ) } ule_crc = iov_crc32(ule_crc, iov, 3); - expected_crc = *((u8 *)priv->ule_skb->tail - 4) << 24 | - *((u8 *)priv->ule_skb->tail - 3) << 16 | - *((u8 *)priv->ule_skb->tail - 2) << 8 | - *((u8 *)priv->ule_skb->tail - 1); + tail = skb_tail_pointer(priv->ule_skb); + expected_crc = *(tail - 4) << 24 | + *(tail - 3) << 16 | + *(tail - 2) << 8 | + *(tail - 1); if (ule_crc != expected_crc) { printk(KERN_WARNING "%lu: CRC32 check FAILED: %08x / %08x, SNDU len %d type %#x, ts_remain %d, next 2: %x.\n", priv->ts_count, ule_crc, expected_crc, priv->ule_sndu_len, priv->ule_sndu_type, ts_remain, ts_remain > 2 ? *(unsigned short *)from_where : 0); |