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Date: Sat, 21 Sep 2013 19:34:28 +0100
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
CC: <netdev@...r.kernel.org>, <linux-net-drivers@...arflare.com>
Subject: [PATCH net-next 05/11] 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@...arflare.com>
---
drivers/net/ethernet/sfc/tx.c | 173 +++++++++++++++++++++++++++++-------------
1 file changed, 121 insertions(+), 52 deletions(-)
diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index 9025356..a23ba0d 100644
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -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;
-
- /* Allocate and insert a DMA-mapped header buffer. */
- header = efx_tsoh_get_buffer(tx_queue, buffer, st->header_len);
- if (!header)
- return -ENOMEM;
+ bool is_last = st->out_len <= skb_shinfo(skb)->gso_size;
+ u8 tcp_flags_clear;
- 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;
+
+ 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;
- tsoh_iph->payload_len = htons(ip_length);
+ /* 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;
}
--
Ben Hutchings, Staff Engineer, Solarflare
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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