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path: root/drivers/net/ethernet/sfc/tx_tso.c
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Diffstat (limited to 'drivers/net/ethernet/sfc/tx_tso.c')
-rw-r--r--drivers/net/ethernet/sfc/tx_tso.c570
1 files changed, 570 insertions, 0 deletions
diff --git a/drivers/net/ethernet/sfc/tx_tso.c b/drivers/net/ethernet/sfc/tx_tso.c
new file mode 100644
index 000000000000..99936d70ed71
--- /dev/null
+++ b/drivers/net/ethernet/sfc/tx_tso.c
@@ -0,0 +1,570 @@
+/****************************************************************************
+ * Driver for Solarflare network controllers and boards
+ * Copyright 2005-2006 Fen Systems Ltd.
+ * Copyright 2005-2015 Solarflare Communications Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation, incorporated herein by reference.
+ */
+
+#include <linux/pci.h>
+#include <linux/tcp.h>
+#include <linux/ip.h>
+#include <linux/in.h>
+#include <linux/ipv6.h>
+#include <linux/slab.h>
+#include <net/ipv6.h>
+#include <linux/if_ether.h>
+#include <linux/highmem.h>
+#include <linux/moduleparam.h>
+#include <linux/cache.h>
+#include "net_driver.h"
+#include "efx.h"
+#include "io.h"
+#include "nic.h"
+#include "tx.h"
+#include "workarounds.h"
+#include "ef10_regs.h"
+
+/* Efx legacy TCP segmentation acceleration.
+ *
+ * Why? Because by doing it here in the driver we can go significantly
+ * faster than the GSO.
+ *
+ * Requires TX checksum offload support.
+ */
+
+#define PTR_DIFF(p1, p2) ((u8 *)(p1) - (u8 *)(p2))
+
+/**
+ * struct tso_state - TSO state for an SKB
+ * @out_len: Remaining length in current segment
+ * @seqnum: Current sequence number
+ * @ipv4_id: Current IPv4 ID, host endian
+ * @packet_space: Remaining space in current packet
+ * @dma_addr: DMA address of current position
+ * @in_len: Remaining length in current SKB fragment
+ * @unmap_len: Length of SKB fragment
+ * @unmap_addr: DMA address of SKB fragment
+ * @dma_flags: TX buffer flags for DMA mapping - %EFX_TX_BUF_MAP_SINGLE or 0
+ * @protocol: Network protocol (after any VLAN header)
+ * @ip_off: Offset of IP header
+ * @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.
+ */
+struct tso_state {
+ /* Output position */
+ unsigned int out_len;
+ unsigned int seqnum;
+ u16 ipv4_id;
+ unsigned int packet_space;
+
+ /* Input position */
+ dma_addr_t dma_addr;
+ unsigned int in_len;
+ unsigned int unmap_len;
+ dma_addr_t unmap_addr;
+ unsigned short dma_flags;
+
+ __be16 protocol;
+ unsigned int ip_off;
+ unsigned int tcp_off;
+ unsigned int header_len;
+ unsigned int ip_base_len;
+ dma_addr_t header_dma_addr;
+ unsigned int header_unmap_len;
+};
+
+static inline void prefetch_ptr(struct efx_tx_queue *tx_queue)
+{
+ unsigned int insert_ptr = efx_tx_queue_get_insert_index(tx_queue);
+ char *ptr;
+
+ ptr = (char *) (tx_queue->buffer + insert_ptr);
+ prefetch(ptr);
+ prefetch(ptr + 0x80);
+
+ ptr = (char *) (((efx_qword_t *)tx_queue->txd.buf.addr) + insert_ptr);
+ prefetch(ptr);
+ prefetch(ptr + 0x80);
+}
+
+/**
+ * efx_tx_queue_insert - push descriptors onto the TX queue
+ * @tx_queue: Efx TX queue
+ * @dma_addr: DMA address of fragment
+ * @len: Length of fragment
+ * @final_buffer: The final buffer inserted into the queue
+ *
+ * Push descriptors onto the TX queue.
+ */
+static void efx_tx_queue_insert(struct efx_tx_queue *tx_queue,
+ dma_addr_t dma_addr, unsigned int len,
+ struct efx_tx_buffer **final_buffer)
+{
+ struct efx_tx_buffer *buffer;
+ unsigned int dma_len;
+
+ EFX_BUG_ON_PARANOID(len <= 0);
+
+ while (1) {
+ buffer = efx_tx_queue_get_insert_buffer(tx_queue);
+ ++tx_queue->insert_count;
+
+ EFX_BUG_ON_PARANOID(tx_queue->insert_count -
+ tx_queue->read_count >=
+ tx_queue->efx->txq_entries);
+
+ buffer->dma_addr = dma_addr;
+
+ dma_len = tx_queue->efx->type->tx_limit_len(tx_queue,
+ dma_addr, len);
+
+ /* If there's space for everything this is our last buffer. */
+ if (dma_len >= len)
+ break;
+
+ buffer->len = dma_len;
+ buffer->flags = EFX_TX_BUF_CONT;
+ dma_addr += dma_len;
+ len -= dma_len;
+ }
+
+ EFX_BUG_ON_PARANOID(!len);
+ buffer->len = len;
+ *final_buffer = buffer;
+}
+
+/*
+ * Verify that our various assumptions about sk_buffs and the conditions
+ * under which TSO will be attempted hold true. Return the protocol number.
+ */
+static __be16 efx_tso_check_protocol(struct sk_buff *skb)
+{
+ __be16 protocol = skb->protocol;
+
+ EFX_BUG_ON_PARANOID(((struct ethhdr *)skb->data)->h_proto !=
+ protocol);
+ if (protocol == htons(ETH_P_8021Q)) {
+ struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
+
+ protocol = veh->h_vlan_encapsulated_proto;
+ }
+
+ if (protocol == htons(ETH_P_IP)) {
+ EFX_BUG_ON_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP);
+ } else {
+ EFX_BUG_ON_PARANOID(protocol != htons(ETH_P_IPV6));
+ EFX_BUG_ON_PARANOID(ipv6_hdr(skb)->nexthdr != NEXTHDR_TCP);
+ }
+ EFX_BUG_ON_PARANOID((PTR_DIFF(tcp_hdr(skb), skb->data)
+ + (tcp_hdr(skb)->doff << 2u)) >
+ skb_headlen(skb));
+
+ return protocol;
+}
+
+static u8 *efx_tsoh_get_buffer(struct efx_tx_queue *tx_queue,
+ struct efx_tx_buffer *buffer, unsigned int len)
+{
+ u8 *result;
+
+ EFX_BUG_ON_PARANOID(buffer->len);
+ EFX_BUG_ON_PARANOID(buffer->flags);
+ EFX_BUG_ON_PARANOID(buffer->unmap_len);
+
+ result = efx_tx_get_copy_buffer_limited(tx_queue, buffer, len);
+
+ if (result) {
+ buffer->flags = EFX_TX_BUF_CONT;
+ } else {
+ buffer->heap_buf = kmalloc(NET_IP_ALIGN + len, GFP_ATOMIC);
+ if (unlikely(!buffer->heap_buf))
+ return NULL;
+ tx_queue->tso_long_headers++;
+ result = (u8 *)buffer->heap_buf + NET_IP_ALIGN;
+ buffer->flags = EFX_TX_BUF_CONT | EFX_TX_BUF_HEAP;
+ }
+
+ buffer->len = len;
+
+ return result;
+}
+
+/*
+ * Put a TSO header into the TX queue.
+ *
+ * This is special-cased because we know that it is small enough to fit in
+ * a single fragment, and we know it doesn't cross a page boundary. It
+ * also allows us to not worry about end-of-packet etc.
+ */
+static int efx_tso_put_header(struct efx_tx_queue *tx_queue,
+ struct efx_tx_buffer *buffer, u8 *header)
+{
+ if (unlikely(buffer->flags & EFX_TX_BUF_HEAP)) {
+ buffer->dma_addr = dma_map_single(&tx_queue->efx->pci_dev->dev,
+ header, buffer->len,
+ DMA_TO_DEVICE);
+ if (unlikely(dma_mapping_error(&tx_queue->efx->pci_dev->dev,
+ buffer->dma_addr))) {
+ kfree(buffer->heap_buf);
+ buffer->len = 0;
+ buffer->flags = 0;
+ return -ENOMEM;
+ }
+ buffer->unmap_len = buffer->len;
+ buffer->dma_offset = 0;
+ buffer->flags |= EFX_TX_BUF_MAP_SINGLE;
+ }
+
+ ++tx_queue->insert_count;
+ return 0;
+}
+
+
+/* Parse the SKB header and initialise state. */
+static int tso_start(struct tso_state *st, struct efx_nic *efx,
+ struct efx_tx_queue *tx_queue,
+ const struct sk_buff *skb)
+{
+ struct device *dma_dev = &efx->pci_dev->dev;
+ unsigned int header_len, in_len;
+ bool use_opt_desc = false;
+ dma_addr_t dma_addr;
+
+ if (tx_queue->tso_version == 1)
+ use_opt_desc = true;
+
+ st->ip_off = skb_network_header(skb) - skb->data;
+ st->tcp_off = skb_transport_header(skb) - skb->data;
+ header_len = st->tcp_off + (tcp_hdr(skb)->doff << 2u);
+ in_len = skb_headlen(skb) - header_len;
+ st->header_len = header_len;
+ st->in_len = in_len;
+ if (st->protocol == htons(ETH_P_IP)) {
+ st->ip_base_len = st->header_len - st->ip_off;
+ st->ipv4_id = ntohs(ip_hdr(skb)->id);
+ } else {
+ st->ip_base_len = st->header_len - st->tcp_off;
+ st->ipv4_id = 0;
+ }
+ st->seqnum = ntohl(tcp_hdr(skb)->seq);
+
+ EFX_BUG_ON_PARANOID(tcp_hdr(skb)->urg);
+ EFX_BUG_ON_PARANOID(tcp_hdr(skb)->syn);
+ EFX_BUG_ON_PARANOID(tcp_hdr(skb)->rst);
+
+ st->out_len = skb->len - header_len;
+
+ if (!use_opt_desc) {
+ 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;
+ st->dma_addr = dma_addr + header_len;
+ st->unmap_len = 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,
+ skb_frag_t *frag)
+{
+ st->unmap_addr = skb_frag_dma_map(&efx->pci_dev->dev, frag, 0,
+ skb_frag_size(frag), DMA_TO_DEVICE);
+ if (likely(!dma_mapping_error(&efx->pci_dev->dev, st->unmap_addr))) {
+ st->dma_flags = 0;
+ st->unmap_len = skb_frag_size(frag);
+ st->in_len = skb_frag_size(frag);
+ st->dma_addr = st->unmap_addr;
+ return 0;
+ }
+ return -ENOMEM;
+}
+
+
+/**
+ * tso_fill_packet_with_fragment - form descriptors for the current fragment
+ * @tx_queue: Efx TX queue
+ * @skb: Socket buffer
+ * @st: TSO state
+ *
+ * Form descriptors for the current fragment, until we reach the end
+ * of fragment or end-of-packet.
+ */
+static void tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue,
+ const struct sk_buff *skb,
+ struct tso_state *st)
+{
+ struct efx_tx_buffer *buffer;
+ int n;
+
+ if (st->in_len == 0)
+ return;
+ if (st->packet_space == 0)
+ return;
+
+ EFX_BUG_ON_PARANOID(st->in_len <= 0);
+ EFX_BUG_ON_PARANOID(st->packet_space <= 0);
+
+ n = min(st->in_len, st->packet_space);
+
+ st->packet_space -= n;
+ st->out_len -= n;
+ st->in_len -= n;
+
+ efx_tx_queue_insert(tx_queue, st->dma_addr, n, &buffer);
+
+ if (st->out_len == 0) {
+ /* Transfer ownership of the skb */
+ buffer->skb = skb;
+ buffer->flags = EFX_TX_BUF_SKB;
+ } else if (st->packet_space != 0) {
+ buffer->flags = EFX_TX_BUF_CONT;
+ }
+
+ if (st->in_len == 0) {
+ /* Transfer ownership of the DMA mapping */
+ buffer->unmap_len = st->unmap_len;
+ buffer->dma_offset = buffer->unmap_len - buffer->len;
+ buffer->flags |= st->dma_flags;
+ st->unmap_len = 0;
+ }
+
+ st->dma_addr += n;
+}
+
+
+#define TCP_FLAGS_OFFSET 13
+
+/**
+ * tso_start_new_packet - generate a new header and prepare for the new packet
+ * @tx_queue: Efx TX queue
+ * @skb: Socket buffer
+ * @st: TSO state
+ *
+ * Generate a new header and prepare for the new packet. Return 0 on
+ * success, or -%ENOMEM if failed to alloc header.
+ */
+static int tso_start_new_packet(struct efx_tx_queue *tx_queue,
+ const struct sk_buff *skb,
+ struct tso_state *st)
+{
+ struct efx_tx_buffer *buffer =
+ efx_tx_queue_get_insert_buffer(tx_queue);
+ bool is_last = st->out_len <= skb_shinfo(skb)->gso_size;
+ u8 tcp_flags_mask;
+
+ if (!is_last) {
+ st->packet_space = skb_shinfo(skb)->gso_size;
+ tcp_flags_mask = 0x09; /* mask out FIN and PSH */
+ } else {
+ st->packet_space = st->out_len;
+ tcp_flags_mask = 0x00;
+ }
+
+ if (!st->header_unmap_len) {
+ /* Allocate and insert a DMA-mapped header buffer. */
+ struct tcphdr *tsoh_th;
+ unsigned int ip_length;
+ u8 *header;
+ int rc;
+
+ 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);
+ ((u8 *)tsoh_th)[TCP_FLAGS_OFFSET] &= ~tcp_flags_mask;
+
+ 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 {
+ /* Send the original headers with a TSO option descriptor
+ * in front
+ */
+ u8 tcp_flags = ((u8 *)tcp_hdr(skb))[TCP_FLAGS_OFFSET] &
+ ~tcp_flags_mask;
+
+ 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 = efx_tx_queue_get_insert_buffer(tx_queue);
+ 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;
+ buffer->dma_offset = 0;
+ /* 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;
+ }
+
+ st->seqnum += skb_shinfo(skb)->gso_size;
+
+ /* Linux leaves suitable gaps in the IP ID space for us to fill. */
+ ++st->ipv4_id;
+
+ return 0;
+}
+
+/**
+ * efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
+ * @tx_queue: Efx TX queue
+ * @skb: Socket buffer
+ * @data_mapped: Did we map the data? Always set to true
+ * by this on success.
+ *
+ * Context: You must hold netif_tx_lock() to call this function.
+ *
+ * Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
+ * @skb was not enqueued. In all cases @skb is consumed. Return
+ * %NETDEV_TX_OK.
+ */
+int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
+ struct sk_buff *skb,
+ bool *data_mapped)
+{
+ struct efx_nic *efx = tx_queue->efx;
+ int frag_i, rc;
+ struct tso_state state;
+
+ prefetch(skb->data);
+
+ /* Find the packet protocol and sanity-check it */
+ state.protocol = efx_tso_check_protocol(skb);
+
+ EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
+
+ rc = tso_start(&state, efx, tx_queue, skb);
+ if (rc)
+ goto mem_err;
+
+ if (likely(state.in_len == 0)) {
+ /* Grab the first payload fragment. */
+ EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1);
+ frag_i = 0;
+ rc = tso_get_fragment(&state, efx,
+ skb_shinfo(skb)->frags + frag_i);
+ if (rc)
+ goto mem_err;
+ } else {
+ /* Payload starts in the header area. */
+ frag_i = -1;
+ }
+
+ if (tso_start_new_packet(tx_queue, skb, &state) < 0)
+ goto mem_err;
+
+ prefetch_ptr(tx_queue);
+
+ while (1) {
+ tso_fill_packet_with_fragment(tx_queue, skb, &state);
+
+ /* Move onto the next fragment? */
+ if (state.in_len == 0) {
+ if (++frag_i >= skb_shinfo(skb)->nr_frags)
+ /* End of payload reached. */
+ break;
+ rc = tso_get_fragment(&state, efx,
+ skb_shinfo(skb)->frags + frag_i);
+ if (rc)
+ goto mem_err;
+ }
+
+ /* Start at new packet? */
+ if (state.packet_space == 0 &&
+ tso_start_new_packet(tx_queue, skb, &state) < 0)
+ goto mem_err;
+ }
+
+ *data_mapped = true;
+
+ return 0;
+
+ mem_err:
+ netif_err(efx, tx_err, efx->net_dev,
+ "Out of memory for TSO headers, or DMA mapping error\n");
+
+ /* Free the DMA mapping we were in the process of writing out */
+ if (state.unmap_len) {
+ if (state.dma_flags & EFX_TX_BUF_MAP_SINGLE)
+ dma_unmap_single(&efx->pci_dev->dev, state.unmap_addr,
+ state.unmap_len, DMA_TO_DEVICE);
+ else
+ dma_unmap_page(&efx->pci_dev->dev, state.unmap_addr,
+ 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);
+
+ return -ENOMEM;
+}
generated by cgit v1.2.3 (git 2.39.0) at 2025-01-06 19:17:34 +0300