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authorArnaldo Carvalho de Melo <acme@redhat.com>2007-04-19 20:29:13 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-25 22:26:28 -0700
commit27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26 (patch)
tree5a267e40f9b94014be38dad5de0a52b6628834e0 /drivers/media/dvb/dvb-core
parentbe8bd86321fa7f06359d866ef61fb4d2f3e9dce9 (diff)
[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/dvb/dvb-core')
-rw-r--r--drivers/media/dvb/dvb-core/dvb_net.c10
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 c6b004182d9..9de177a5b9f 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);