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sfc: Implement firmware-assisted TSO for EF10 

Segmentation remains in the driver, but we generate option descriptors
describing the required packet editing rather than making our own
copies.

Reduce tso_state::ipv4_id to 16 bits, so it doesn't overflow into the
TCP_FLAGS field of the option descriptor.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
This commit is contained in:
Ben Hutchings 2013-03-08 21:20:09 +00:00
parent c78c39e67c
commit dfa50be95c
1 changed files with 121 additions and 52 deletions
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173
drivers/net/ethernet/sfc/tx.c
View File

@ -21,6 +21,7 @@
#include "efx.h"
#include "nic.h"
#include "workarounds.h"
#include "ef10_regs.h"
static void efx_dequeue_buffer(struct efx_tx_queue *tx_queue,
struct efx_tx_buffer *buffer,
@ -83,8 +84,10 @@ unsigned int efx_tx_max_skb_descs(struct efx_nic *efx)
*/
unsigned int max_descs = EFX_TSO_MAX_SEGS * 2 + MAX_SKB_FRAGS;
/* Possibly one more per segment for the alignment workaround */
if (EFX_WORKAROUND_5391(efx))
/* Possibly one more per segment for the alignment workaround,
* or for option descriptors
*/
if (EFX_WORKAROUND_5391(efx) || efx_nic_rev(efx) >= EFX_REV_HUNT_A0)
max_descs += EFX_TSO_MAX_SEGS;
/* Possibly more for PCIe page boundaries within input fragments */
@ -628,6 +631,9 @@ void efx_remove_tx_queue(struct efx_tx_queue *tx_queue)
* @tcp_off: Offset of TCP header
* @header_len: Number of bytes of header
* @ip_base_len: IPv4 tot_len or IPv6 payload_len, before TCP payload
* @header_dma_addr: Header DMA address, when using option descriptors
* @header_unmap_len: Header DMA mapped length, or 0 if not using option
* descriptors
*
* The state used during segmentation. It is put into this data structure
* just to make it easy to pass into inline functions.
@ -636,7 +642,7 @@ struct tso_state {
/* Output position */
unsigned out_len;
unsigned seqnum;
unsigned ipv4_id;
u16 ipv4_id;
unsigned packet_space;
/* Input position */
@ -651,6 +657,8 @@ struct tso_state {
unsigned int tcp_off;
unsigned header_len;
unsigned int ip_base_len;
dma_addr_t header_dma_addr;
unsigned int header_unmap_len;
};
@ -825,7 +833,10 @@ static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
static int tso_start(struct tso_state *st, struct efx_nic *efx,
const struct sk_buff *skb)
{
bool use_options = efx_nic_rev(efx) >= EFX_REV_HUNT_A0;
struct device *dma_dev = &efx->pci_dev->dev;
unsigned int header_len, in_len;
dma_addr_t dma_addr;
st->ip_off = skb_network_header(skb) - skb->data;
st->tcp_off = skb_transport_header(skb) - skb->data;
@ -848,22 +859,32 @@ static int tso_start(struct tso_state *st, struct efx_nic *efx,
st->out_len = skb->len - header_len;
if (likely(in_len == 0)) {
st->unmap_len = 0;
if (!use_options) {
st->header_unmap_len = 0;
if (likely(in_len == 0)) {
st->dma_flags = 0;
st->unmap_len = 0;
return 0;
}
dma_addr = dma_map_single(dma_dev, skb->data + header_len,
in_len, DMA_TO_DEVICE);
st->dma_flags = EFX_TX_BUF_MAP_SINGLE;
st->dma_addr = dma_addr;
st->unmap_addr = dma_addr;
st->unmap_len = in_len;
} else {
dma_addr = dma_map_single(dma_dev, skb->data,
skb_headlen(skb), DMA_TO_DEVICE);
st->header_dma_addr = dma_addr;
st->header_unmap_len = skb_headlen(skb);
st->dma_flags = 0;
return 0;
st->dma_addr = dma_addr + header_len;
st->unmap_len = 0;
}
st->unmap_addr = dma_map_single(&efx->pci_dev->dev,
skb->data + header_len, in_len,
DMA_TO_DEVICE);
if (unlikely(dma_mapping_error(&efx->pci_dev->dev, st->unmap_addr)))
return -ENOMEM;
st->dma_flags = EFX_TX_BUF_MAP_SINGLE;
st->unmap_len = in_len;
st->dma_addr = st->unmap_addr;
return 0;
return unlikely(dma_mapping_error(dma_dev, dma_addr)) ? -ENOMEM : 0;
}
static int tso_get_fragment(struct tso_state *st, struct efx_nic *efx,
@ -948,54 +969,97 @@ static int tso_start_new_packet(struct efx_tx_queue *tx_queue,
{
struct efx_tx_buffer *buffer =
&tx_queue->buffer[tx_queue->insert_count & tx_queue->ptr_mask];
struct tcphdr *tsoh_th;
unsigned ip_length;
u8 *header;
int rc;
bool is_last = st->out_len <= skb_shinfo(skb)->gso_size;
u8 tcp_flags_clear;
/* Allocate and insert a DMA-mapped header buffer. */
header = efx_tsoh_get_buffer(tx_queue, buffer, st->header_len);
if (!header)
return -ENOMEM;
tsoh_th = (struct tcphdr *)(header + st->tcp_off);
/* Copy and update the headers. */
memcpy(header, skb->data, st->header_len);
tsoh_th->seq = htonl(st->seqnum);
st->seqnum += skb_shinfo(skb)->gso_size;
if (st->out_len > skb_shinfo(skb)->gso_size) {
/* This packet will not finish the TSO burst. */
if (!is_last) {
st->packet_space = skb_shinfo(skb)->gso_size;
tsoh_th->fin = 0;
tsoh_th->psh = 0;
tcp_flags_clear = 0x09; /* mask out FIN and PSH */
} else {
/* This packet will be the last in the TSO burst. */
st->packet_space = st->out_len;
tsoh_th->fin = tcp_hdr(skb)->fin;
tsoh_th->psh = tcp_hdr(skb)->psh;
tcp_flags_clear = 0x00;
}
ip_length = st->ip_base_len + st->packet_space;
if (st->protocol == htons(ETH_P_IP)) {
struct iphdr *tsoh_iph = (struct iphdr *)(header + st->ip_off);
if (!st->header_unmap_len) {
/* Allocate and insert a DMA-mapped header buffer. */
struct tcphdr *tsoh_th;
unsigned ip_length;
u8 *header;
int rc;
tsoh_iph->tot_len = htons(ip_length);
header = efx_tsoh_get_buffer(tx_queue, buffer, st->header_len);
if (!header)
return -ENOMEM;
/* Linux leaves suitable gaps in the IP ID space for us to fill. */
tsoh_iph->id = htons(st->ipv4_id);
st->ipv4_id++;
tsoh_th = (struct tcphdr *)(header + st->tcp_off);
/* Copy and update the headers. */
memcpy(header, skb->data, st->header_len);
tsoh_th->seq = htonl(st->seqnum);
((u8 *)tsoh_th)[13] &= ~tcp_flags_clear;
ip_length = st->ip_base_len + st->packet_space;
if (st->protocol == htons(ETH_P_IP)) {
struct iphdr *tsoh_iph =
(struct iphdr *)(header + st->ip_off);
tsoh_iph->tot_len = htons(ip_length);
tsoh_iph->id = htons(st->ipv4_id);
} else {
struct ipv6hdr *tsoh_iph =
(struct ipv6hdr *)(header + st->ip_off);
tsoh_iph->payload_len = htons(ip_length);
}
rc = efx_tso_put_header(tx_queue, buffer, header);
if (unlikely(rc))
return rc;
} else {
struct ipv6hdr *tsoh_iph =
(struct ipv6hdr *)(header + st->ip_off);
/* Send the original headers with a TSO option descriptor
* in front
*/
u8 tcp_flags = ((u8 *)tcp_hdr(skb))[13] & ~tcp_flags_clear;
tsoh_iph->payload_len = htons(ip_length);
buffer->flags = EFX_TX_BUF_OPTION;
buffer->len = 0;
buffer->unmap_len = 0;
EFX_POPULATE_QWORD_5(buffer->option,
ESF_DZ_TX_DESC_IS_OPT, 1,
ESF_DZ_TX_OPTION_TYPE,
ESE_DZ_TX_OPTION_DESC_TSO,
ESF_DZ_TX_TSO_TCP_FLAGS, tcp_flags,
ESF_DZ_TX_TSO_IP_ID, st->ipv4_id,
ESF_DZ_TX_TSO_TCP_SEQNO, st->seqnum);
++tx_queue->insert_count;
/* We mapped the headers in tso_start(). Unmap them
* when the last segment is completed.
*/
buffer = &tx_queue->buffer[tx_queue->insert_count &
tx_queue->ptr_mask];
buffer->dma_addr = st->header_dma_addr;
buffer->len = st->header_len;
if (is_last) {
buffer->flags = EFX_TX_BUF_CONT | EFX_TX_BUF_MAP_SINGLE;
buffer->unmap_len = st->header_unmap_len;
/* Ensure we only unmap them once in case of a
* later DMA mapping error and rollback
*/
st->header_unmap_len = 0;
} else {
buffer->flags = EFX_TX_BUF_CONT;
buffer->unmap_len = 0;
}
++tx_queue->insert_count;
}
rc = efx_tso_put_header(tx_queue, buffer, header);
if (unlikely(rc))
return rc;
st->seqnum += skb_shinfo(skb)->gso_size;
/* Linux leaves suitable gaps in the IP ID space for us to fill. */
++st->ipv4_id;
++tx_queue->tso_packets;
@ -1091,6 +1155,11 @@ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
state.unmap_len, DMA_TO_DEVICE);
}
/* Free the header DMA mapping, if using option descriptors */
if (state.header_unmap_len)
dma_unmap_single(&efx->pci_dev->dev, state.header_dma_addr,
state.header_unmap_len, DMA_TO_DEVICE);
efx_enqueue_unwind(tx_queue);
return NETDEV_TX_OK;
}