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Date: Tue, 01 Mar 2011 01:22:16 +0000
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
Cc: linux-net-drivers@...arflare.com, netdev <netdev@...r.kernel.org>
Subject: [PATCH net-next-2.6 2/8] sfc: Reduce size of efx_rx_buffer further
by removing data member
From: Steve Hodgson <shodgson@...arflare.com>
Instead calculate the KVA of receive data. It's not like it's a hard sum.
[bwh: Fixed to work with GRO.]
Signed-off-by: Ben Hutchings <bhutchings@...arflare.com>
---
drivers/net/sfc/net_driver.h | 2 -
drivers/net/sfc/rx.c | 50 +++++++++++++++++++++++------------------
2 files changed, 28 insertions(+), 24 deletions(-)
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index 59ff32a..5b001c1 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -214,7 +214,6 @@ struct efx_tx_queue {
* If both this and page are %NULL, the buffer slot is currently free.
* @page: The associated page buffer, if any.
* If both this and skb are %NULL, the buffer slot is currently free.
- * @data: Pointer to ethernet header
* @len: Buffer length, in bytes.
* @is_page: Indicates if @page is valid. If false, @skb is valid.
*/
@@ -224,7 +223,6 @@ struct efx_rx_buffer {
struct sk_buff *skb;
struct page *page;
} u;
- char *data;
unsigned int len;
bool is_page;
};
diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c
index bcbd2ec..81bec87 100644
--- a/drivers/net/sfc/rx.c
+++ b/drivers/net/sfc/rx.c
@@ -89,24 +89,37 @@ static unsigned int rx_refill_limit = 95;
*/
#define EFX_RXD_HEAD_ROOM 2
-static inline unsigned int efx_rx_buf_offset(struct efx_rx_buffer *buf)
+/* Offset of ethernet header within page */
+static inline unsigned int efx_rx_buf_offset(struct efx_nic *efx,
+ struct efx_rx_buffer *buf)
{
/* Offset is always within one page, so we don't need to consider
* the page order.
*/
- return (__force unsigned long) buf->data & (PAGE_SIZE - 1);
+ return (((__force unsigned long) buf->dma_addr & (PAGE_SIZE - 1)) +
+ efx->type->rx_buffer_hash_size);
}
static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)
{
return PAGE_SIZE << efx->rx_buffer_order;
}
-static inline u32 efx_rx_buf_hash(struct efx_rx_buffer *buf)
+static u8 *efx_rx_buf_eh(struct efx_nic *efx, struct efx_rx_buffer *buf)
{
+ if (buf->is_page)
+ return page_address(buf->u.page) + efx_rx_buf_offset(efx, buf);
+ else
+ return ((u8 *)buf->u.skb->data +
+ efx->type->rx_buffer_hash_size);
+}
+
+static inline u32 efx_rx_buf_hash(const u8 *eh)
+{
+ /* The ethernet header is always directly after any hash. */
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || NET_IP_ALIGN % 4 == 0
- return __le32_to_cpup((const __le32 *)(buf->data - 4));
+ return __le32_to_cpup((const __le32 *)(eh - 4));
#else
- const u8 *data = (const u8 *)(buf->data - 4);
+ const u8 *data = eh - 4;
return ((u32)data[0] |
(u32)data[1] << 8 |
(u32)data[2] << 16 |
@@ -143,13 +156,12 @@ static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue)
/* Adjust the SKB for padding and checksum */
skb_reserve(skb, NET_IP_ALIGN);
- rx_buf->data = (char *)skb->data;
rx_buf->len = skb_len - NET_IP_ALIGN;
rx_buf->is_page = false;
skb->ip_summed = CHECKSUM_UNNECESSARY;
rx_buf->dma_addr = pci_map_single(efx->pci_dev,
- rx_buf->data, rx_buf->len,
+ skb->data, rx_buf->len,
PCI_DMA_FROMDEVICE);
if (unlikely(pci_dma_mapping_error(efx->pci_dev,
rx_buf->dma_addr))) {
@@ -213,7 +225,6 @@ static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
rx_buf = efx_rx_buffer(rx_queue, index);
rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN;
rx_buf->u.page = page;
- rx_buf->data = page_addr + EFX_PAGE_IP_ALIGN;
rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
rx_buf->is_page = true;
++rx_queue->added_count;
@@ -297,8 +308,6 @@ static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue,
new_buf = efx_rx_buffer(rx_queue, index);
new_buf->dma_addr = rx_buf->dma_addr ^ (PAGE_SIZE >> 1);
new_buf->u.page = rx_buf->u.page;
- new_buf->data = (void *)
- ((__force unsigned long)rx_buf->data ^ (PAGE_SIZE >> 1));
new_buf->len = rx_buf->len;
new_buf->is_page = true;
++rx_queue->added_count;
@@ -446,7 +455,7 @@ static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
*/
static void efx_rx_packet_gro(struct efx_channel *channel,
struct efx_rx_buffer *rx_buf,
- bool checksummed)
+ const u8 *eh, bool checksummed)
{
struct napi_struct *napi = &channel->napi_str;
gro_result_t gro_result;
@@ -466,11 +475,11 @@ static void efx_rx_packet_gro(struct efx_channel *channel,
}
if (efx->net_dev->features & NETIF_F_RXHASH)
- skb->rxhash = efx_rx_buf_hash(rx_buf);
+ skb->rxhash = efx_rx_buf_hash(eh);
skb_shinfo(skb)->frags[0].page = page;
skb_shinfo(skb)->frags[0].page_offset =
- efx_rx_buf_offset(rx_buf);
+ efx_rx_buf_offset(efx, rx_buf);
skb_shinfo(skb)->frags[0].size = rx_buf->len;
skb_shinfo(skb)->nr_frags = 1;
@@ -509,7 +518,6 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
bool leak_packet = false;
rx_buf = efx_rx_buffer(rx_queue, index);
- EFX_BUG_ON_PARANOID(!rx_buf->data);
/* This allows the refill path to post another buffer.
* EFX_RXD_HEAD_ROOM ensures that the slot we are using
@@ -548,12 +556,12 @@ void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
/* Prefetch nice and early so data will (hopefully) be in cache by
* the time we look at it.
*/
- prefetch(rx_buf->data);
+ prefetch(efx_rx_buf_eh(efx, rx_buf));
/* Pipeline receives so that we give time for packet headers to be
* prefetched into cache.
*/
- rx_buf->len = len;
+ rx_buf->len = len - efx->type->rx_buffer_hash_size;
out:
if (channel->rx_pkt)
__efx_rx_packet(channel,
@@ -568,15 +576,13 @@ void __efx_rx_packet(struct efx_channel *channel,
{
struct efx_nic *efx = channel->efx;
struct sk_buff *skb;
-
- rx_buf->data += efx->type->rx_buffer_hash_size;
- rx_buf->len -= efx->type->rx_buffer_hash_size;
+ u8 *eh = efx_rx_buf_eh(efx, rx_buf);
/* If we're in loopback test, then pass the packet directly to the
* loopback layer, and free the rx_buf here
*/
if (unlikely(efx->loopback_selftest)) {
- efx_loopback_rx_packet(efx, rx_buf->data, rx_buf->len);
+ efx_loopback_rx_packet(efx, eh, rx_buf->len);
efx_free_rx_buffer(efx, rx_buf);
return;
}
@@ -590,7 +596,7 @@ void __efx_rx_packet(struct efx_channel *channel,
skb_put(skb, rx_buf->len);
if (efx->net_dev->features & NETIF_F_RXHASH)
- skb->rxhash = efx_rx_buf_hash(rx_buf);
+ skb->rxhash = efx_rx_buf_hash(eh);
/* Move past the ethernet header. rx_buf->data still points
* at the ethernet header */
@@ -600,7 +606,7 @@ void __efx_rx_packet(struct efx_channel *channel,
}
if (likely(checksummed || rx_buf->is_page)) {
- efx_rx_packet_gro(channel, rx_buf, checksummed);
+ efx_rx_packet_gro(channel, rx_buf, eh, checksummed);
return;
}
--
1.5.4
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
--
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