From 27a884dc3cb63b93c2b3b643f5b31eed5f8a4d26 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 19 Apr 2007 20:29:13 -0700 Subject: [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 Signed-off-by: David S. Miller --- drivers/usb/atm/usbatm.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/usb/atm') diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c index ec63b0ee074..4d8f282b23d 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", -- cgit v1.2.3