diff options
| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2007-04-19 20:29:13 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-04-25 22:26:28 -0700 |
| commit | 27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26 (patch) | |
| tree | 5a267e40f9b94014be38dad5de0a52b6628834e0 /drivers/usb/atm/usbatm.c | |
| parent | be8bd86321fa7f06359d866ef61fb4d2f3e9dce9 (diff) | |
| download | linux-27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26.tar.bz2 | |
[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/usb/atm/usbatm.c')
| -rw-r--r-- | drivers/usb/atm/usbatm.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c index ec63b0ee0743..4d8f282b23d1 100644 --- a/drivers/usb/atm/usbatm.c +++ b/drivers/usb/atm/usbatm.c @@ -335,15 +335,15 @@ static void usbatm_extract_one_cell(struct usbatm_data *instance, unsigned char sarb = instance->cached_vcc->sarb; - if (sarb->tail + ATM_CELL_PAYLOAD > sarb->end) { + if (skb_tail_pointer(sarb) + ATM_CELL_PAYLOAD > sarb->end) { atm_rldbg(instance, "%s: buffer overrun (sarb->len %u, vcc: 0x%p)!\n", __func__, sarb->len, vcc); /* discard cells already received */ skb_trim(sarb, 0); - UDSL_ASSERT(sarb->tail + ATM_CELL_PAYLOAD <= sarb->end); + UDSL_ASSERT(skb_tail_pointer(sarb) + ATM_CELL_PAYLOAD <= sarb->end); } - memcpy(sarb->tail, source + ATM_CELL_HEADER, ATM_CELL_PAYLOAD); + memcpy(skb_tail_pointer(sarb), source + ATM_CELL_HEADER, ATM_CELL_PAYLOAD); __skb_put(sarb, ATM_CELL_PAYLOAD); if (pti & 1) { @@ -370,7 +370,7 @@ static void usbatm_extract_one_cell(struct usbatm_data *instance, unsigned char goto out; } - if (crc32_be(~0, sarb->tail - pdu_length, pdu_length) != 0xc704dd7b) { + if (crc32_be(~0, skb_tail_pointer(sarb) - pdu_length, pdu_length) != 0xc704dd7b) { atm_rldbg(instance, "%s: packet failed crc check (vcc: 0x%p)!\n", __func__, vcc); atomic_inc(&vcc->stats->rx_err); @@ -396,7 +396,7 @@ static void usbatm_extract_one_cell(struct usbatm_data *instance, unsigned char goto out; /* atm_charge increments rx_drop */ } - memcpy(skb->data, sarb->tail - pdu_length, length); + memcpy(skb->data, skb_tail_pointer(sarb) - pdu_length, length); __skb_put(skb, length); vdbg("%s: sending skb 0x%p, skb->len %u, skb->truesize %u", |