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OpenCloudOS-Kernel/drivers/net/ethernet/sfc/tx.c

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/****************************************************************************
* Driver for Solarflare Solarstorm network controllers and boards
* Copyright 2005-2006 Fen Systems Ltd.
* Copyright 2005-2010 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 "net_driver.h"
#include "efx.h"
#include "nic.h"
#include "workarounds.h"
static void efx_dequeue_buffer(struct efx_tx_queue *tx_queue,
struct efx_tx_buffer *buffer,
unsigned int *pkts_compl,
unsigned int *bytes_compl)
{
if (buffer->unmap_len) {
struct device *dma_dev = &tx_queue->efx->pci_dev->dev;
dma_addr_t unmap_addr = (buffer->dma_addr + buffer->len -
buffer->unmap_len);
if (buffer->flags & EFX_TX_BUF_MAP_SINGLE)
dma_unmap_single(dma_dev, unmap_addr, buffer->unmap_len,
DMA_TO_DEVICE);
else
dma_unmap_page(dma_dev, unmap_addr, buffer->unmap_len,
DMA_TO_DEVICE);
buffer->unmap_len = 0;
}
if (buffer->flags & EFX_TX_BUF_SKB) {
(*pkts_compl)++;
(*bytes_compl) += buffer->skb->len;
dev_kfree_skb_any((struct sk_buff *) buffer->skb);
netif_vdbg(tx_queue->efx, tx_done, tx_queue->efx->net_dev,
"TX queue %d transmission id %x complete\n",
tx_queue->queue, tx_queue->read_count);
} else if (buffer->flags & EFX_TX_BUF_HEAP) {
kfree(buffer->heap_buf);
}
buffer->len = 0;
buffer->flags = 0;
}
static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
struct sk_buff *skb);
static inline unsigned
efx_max_tx_len(struct efx_nic *efx, dma_addr_t dma_addr)
{
/* Depending on the NIC revision, we can use descriptor
* lengths up to 8K or 8K-1. However, since PCI Express
* devices must split read requests at 4K boundaries, there is
* little benefit from using descriptors that cross those
* boundaries and we keep things simple by not doing so.
*/
unsigned len = (~dma_addr & (EFX_PAGE_SIZE - 1)) + 1;
/* Work around hardware bug for unaligned buffers. */
if (EFX_WORKAROUND_5391(efx) && (dma_addr & 0xf))
len = min_t(unsigned, len, 512 - (dma_addr & 0xf));
return len;
}
unsigned int efx_tx_max_skb_descs(struct efx_nic *efx)
{
/* Header and payload descriptor for each output segment, plus
* one for every input fragment boundary within a segment
*/
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))
max_descs += EFX_TSO_MAX_SEGS;
/* Possibly more for PCIe page boundaries within input fragments */
if (PAGE_SIZE > EFX_PAGE_SIZE)
max_descs += max_t(unsigned int, MAX_SKB_FRAGS,
DIV_ROUND_UP(GSO_MAX_SIZE, EFX_PAGE_SIZE));
return max_descs;
}
/* Get partner of a TX queue, seen as part of the same net core queue */
static struct efx_tx_queue *efx_tx_queue_partner(struct efx_tx_queue *tx_queue)
{
if (tx_queue->queue & EFX_TXQ_TYPE_OFFLOAD)
return tx_queue - EFX_TXQ_TYPE_OFFLOAD;
else
return tx_queue + EFX_TXQ_TYPE_OFFLOAD;
}
static void efx_tx_maybe_stop_queue(struct efx_tx_queue *txq1)
{
/* We need to consider both queues that the net core sees as one */
struct efx_tx_queue *txq2 = efx_tx_queue_partner(txq1);
struct efx_nic *efx = txq1->efx;
unsigned int fill_level;
fill_level = max(txq1->insert_count - txq1->old_read_count,
txq2->insert_count - txq2->old_read_count);
if (likely(fill_level < efx->txq_stop_thresh))
return;
/* We used the stale old_read_count above, which gives us a
* pessimistic estimate of the fill level (which may even
* validly be >= efx->txq_entries). Now try again using
* read_count (more likely to be a cache miss).
*
* If we read read_count and then conditionally stop the
* queue, it is possible for the completion path to race with
* us and complete all outstanding descriptors in the middle,
* after which there will be no more completions to wake it.
* Therefore we stop the queue first, then read read_count
* (with a memory barrier to ensure the ordering), then
* restart the queue if the fill level turns out to be low
* enough.
*/
netif_tx_stop_queue(txq1->core_txq);
smp_mb();
txq1->old_read_count = ACCESS_ONCE(txq1->read_count);
txq2->old_read_count = ACCESS_ONCE(txq2->read_count);
fill_level = max(txq1->insert_count - txq1->old_read_count,
txq2->insert_count - txq2->old_read_count);
EFX_BUG_ON_PARANOID(fill_level >= efx->txq_entries);
if (likely(fill_level < efx->txq_stop_thresh)) {
smp_mb();
if (likely(!efx->loopback_selftest))
netif_tx_start_queue(txq1->core_txq);
}
}
/*
* Add a socket buffer to a TX queue
*
* This maps all fragments of a socket buffer for DMA and adds them to
* the TX queue. The queue's insert pointer will be incremented by
* the number of fragments in the socket buffer.
*
* If any DMA mapping fails, any mapped fragments will be unmapped,
* the queue's insert pointer will be restored to its original value.
*
* This function is split out from efx_hard_start_xmit to allow the
* loopback test to direct packets via specific TX queues.
*
* Returns NETDEV_TX_OK.
* You must hold netif_tx_lock() to call this function.
*/
netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
{
struct efx_nic *efx = tx_queue->efx;
struct device *dma_dev = &efx->pci_dev->dev;
struct efx_tx_buffer *buffer;
skb_frag_t *fragment;
unsigned int len, unmap_len = 0, insert_ptr;
dma_addr_t dma_addr, unmap_addr = 0;
unsigned int dma_len;
unsigned short dma_flags;
int i = 0;
EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
if (skb_shinfo(skb)->gso_size)
return efx_enqueue_skb_tso(tx_queue, skb);
/* Get size of the initial fragment */
len = skb_headlen(skb);
/* Pad if necessary */
if (EFX_WORKAROUND_15592(efx) && skb->len <= 32) {
EFX_BUG_ON_PARANOID(skb->data_len);
len = 32 + 1;
if (skb_pad(skb, len - skb->len))
return NETDEV_TX_OK;
}
/* Map for DMA. Use dma_map_single rather than dma_map_page
* since this is more efficient on machines with sparse
* memory.
*/
dma_flags = EFX_TX_BUF_MAP_SINGLE;
dma_addr = dma_map_single(dma_dev, skb->data, len, PCI_DMA_TODEVICE);
/* Process all fragments */
while (1) {
if (unlikely(dma_mapping_error(dma_dev, dma_addr)))
goto dma_err;
/* Store fields for marking in the per-fragment final
* descriptor */
unmap_len = len;
unmap_addr = dma_addr;
/* Add to TX queue, splitting across DMA boundaries */
do {
insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
buffer = &tx_queue->buffer[insert_ptr];
EFX_BUG_ON_PARANOID(buffer->flags);
EFX_BUG_ON_PARANOID(buffer->len);
EFX_BUG_ON_PARANOID(buffer->unmap_len);
dma_len = efx_max_tx_len(efx, dma_addr);
if (likely(dma_len >= len))
dma_len = len;
/* Fill out per descriptor fields */
buffer->len = dma_len;
buffer->dma_addr = dma_addr;
buffer->flags = EFX_TX_BUF_CONT;
len -= dma_len;
dma_addr += dma_len;
++tx_queue->insert_count;
} while (len);
/* Transfer ownership of the unmapping to the final buffer */
buffer->flags = EFX_TX_BUF_CONT | dma_flags;
buffer->unmap_len = unmap_len;
unmap_len = 0;
/* Get address and size of next fragment */
if (i >= skb_shinfo(skb)->nr_frags)
break;
fragment = &skb_shinfo(skb)->frags[i];
len = skb_frag_size(fragment);
i++;
/* Map for DMA */
dma_flags = 0;
dma_addr = skb_frag_dma_map(dma_dev, fragment, 0, len,
DMA_TO_DEVICE);
}
/* Transfer ownership of the skb to the final buffer */
buffer->skb = skb;
buffer->flags = EFX_TX_BUF_SKB | dma_flags;
netdev_tx_sent_queue(tx_queue->core_txq, skb->len);
/* Pass off to hardware */
efx_nic_push_buffers(tx_queue);
efx_tx_maybe_stop_queue(tx_queue);
return NETDEV_TX_OK;
dma_err:
netif_err(efx, tx_err, efx->net_dev,
" TX queue %d could not map skb with %d bytes %d "
"fragments for DMA\n", tx_queue->queue, skb->len,
skb_shinfo(skb)->nr_frags + 1);
/* Mark the packet as transmitted, and free the SKB ourselves */
dev_kfree_skb_any(skb);
/* Work backwards until we hit the original insert pointer value */
while (tx_queue->insert_count != tx_queue->write_count) {
unsigned int pkts_compl = 0, bytes_compl = 0;
--tx_queue->insert_count;
insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
buffer = &tx_queue->buffer[insert_ptr];
efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl);
}
/* Free the fragment we were mid-way through pushing */
if (unmap_len) {
if (dma_flags & EFX_TX_BUF_MAP_SINGLE)
dma_unmap_single(dma_dev, unmap_addr, unmap_len,
DMA_TO_DEVICE);
else
dma_unmap_page(dma_dev, unmap_addr, unmap_len,
DMA_TO_DEVICE);
}
return NETDEV_TX_OK;
}
/* Remove packets from the TX queue
*
* This removes packets from the TX queue, up to and including the
* specified index.
*/
static void efx_dequeue_buffers(struct efx_tx_queue *tx_queue,
unsigned int index,
unsigned int *pkts_compl,
unsigned int *bytes_compl)
{
struct efx_nic *efx = tx_queue->efx;
unsigned int stop_index, read_ptr;
stop_index = (index + 1) & tx_queue->ptr_mask;
read_ptr = tx_queue->read_count & tx_queue->ptr_mask;
while (read_ptr != stop_index) {
struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr];
if (unlikely(buffer->len == 0)) {
netif_err(efx, tx_err, efx->net_dev,
"TX queue %d spurious TX completion id %x\n",
tx_queue->queue, read_ptr);
efx_schedule_reset(efx, RESET_TYPE_TX_SKIP);
return;
}
efx_dequeue_buffer(tx_queue, buffer, pkts_compl, bytes_compl);
++tx_queue->read_count;
read_ptr = tx_queue->read_count & tx_queue->ptr_mask;
}
}
/* Initiate a packet transmission. We use one channel per CPU
* (sharing when we have more CPUs than channels). On Falcon, the TX
* completion events will be directed back to the CPU that transmitted
* the packet, which should be cache-efficient.
*
* Context: non-blocking.
* Note that returning anything other than NETDEV_TX_OK will cause the
* OS to free the skb.
*/
netdev_tx_t efx_hard_start_xmit(struct sk_buff *skb,
struct net_device *net_dev)
{
struct efx_nic *efx = netdev_priv(net_dev);
struct efx_tx_queue *tx_queue;
unsigned index, type;
EFX_WARN_ON_PARANOID(!netif_device_present(net_dev));
/* PTP "event" packet */
if (unlikely(efx_xmit_with_hwtstamp(skb)) &&
unlikely(efx_ptp_is_ptp_tx(efx, skb))) {
return efx_ptp_tx(efx, skb);
}
index = skb_get_queue_mapping(skb);
type = skb->ip_summed == CHECKSUM_PARTIAL ? EFX_TXQ_TYPE_OFFLOAD : 0;
if (index >= efx->n_tx_channels) {
index -= efx->n_tx_channels;
type |= EFX_TXQ_TYPE_HIGHPRI;
}
tx_queue = efx_get_tx_queue(efx, index, type);
return efx_enqueue_skb(tx_queue, skb);
}
void efx_init_tx_queue_core_txq(struct efx_tx_queue *tx_queue)
{
struct efx_nic *efx = tx_queue->efx;
/* Must be inverse of queue lookup in efx_hard_start_xmit() */
tx_queue->core_txq =
netdev_get_tx_queue(efx->net_dev,
tx_queue->queue / EFX_TXQ_TYPES +
((tx_queue->queue & EFX_TXQ_TYPE_HIGHPRI) ?
efx->n_tx_channels : 0));
}
int efx_setup_tc(struct net_device *net_dev, u8 num_tc)
{
struct efx_nic *efx = netdev_priv(net_dev);
struct efx_channel *channel;
struct efx_tx_queue *tx_queue;
unsigned tc;
int rc;
if (efx_nic_rev(efx) < EFX_REV_FALCON_B0 || num_tc > EFX_MAX_TX_TC)
return -EINVAL;
if (num_tc == net_dev->num_tc)
return 0;
for (tc = 0; tc < num_tc; tc++) {
net_dev->tc_to_txq[tc].offset = tc * efx->n_tx_channels;
net_dev->tc_to_txq[tc].count = efx->n_tx_channels;
}
if (num_tc > net_dev->num_tc) {
/* Initialise high-priority queues as necessary */
efx_for_each_channel(channel, efx) {
efx_for_each_possible_channel_tx_queue(tx_queue,
channel) {
if (!(tx_queue->queue & EFX_TXQ_TYPE_HIGHPRI))
continue;
if (!tx_queue->buffer) {
rc = efx_probe_tx_queue(tx_queue);
if (rc)
return rc;
}
if (!tx_queue->initialised)
efx_init_tx_queue(tx_queue);
efx_init_tx_queue_core_txq(tx_queue);
}
}
} else {
/* Reduce number of classes before number of queues */
net_dev->num_tc = num_tc;
}
rc = netif_set_real_num_tx_queues(net_dev,
max_t(int, num_tc, 1) *
efx->n_tx_channels);
if (rc)
return rc;
/* Do not destroy high-priority queues when they become
* unused. We would have to flush them first, and it is
* fairly difficult to flush a subset of TX queues. Leave
* it to efx_fini_channels().
*/
net_dev->num_tc = num_tc;
return 0;
}
void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index)
{
unsigned fill_level;
struct efx_nic *efx = tx_queue->efx;
struct efx_tx_queue *txq2;
unsigned int pkts_compl = 0, bytes_compl = 0;
EFX_BUG_ON_PARANOID(index > tx_queue->ptr_mask);
efx_dequeue_buffers(tx_queue, index, &pkts_compl, &bytes_compl);
netdev_tx_completed_queue(tx_queue->core_txq, pkts_compl, bytes_compl);
/* See if we need to restart the netif queue. This memory
* barrier ensures that we write read_count (inside
* efx_dequeue_buffers()) before reading the queue status.
*/
smp_mb();
if (unlikely(netif_tx_queue_stopped(tx_queue->core_txq)) &&
likely(efx->port_enabled) &&
likely(netif_device_present(efx->net_dev))) {
txq2 = efx_tx_queue_partner(tx_queue);
fill_level = max(tx_queue->insert_count - tx_queue->read_count,
txq2->insert_count - txq2->read_count);
if (fill_level <= efx->txq_wake_thresh)
netif_tx_wake_queue(tx_queue->core_txq);
}
/* Check whether the hardware queue is now empty */
if ((int)(tx_queue->read_count - tx_queue->old_write_count) >= 0) {
tx_queue->old_write_count = ACCESS_ONCE(tx_queue->write_count);
if (tx_queue->read_count == tx_queue->old_write_count) {
smp_mb();
tx_queue->empty_read_count =
tx_queue->read_count | EFX_EMPTY_COUNT_VALID;
}
}
}
/* Size of page-based TSO header buffers. Larger blocks must be
* allocated from the heap.
*/
#define TSOH_STD_SIZE 128
#define TSOH_PER_PAGE (PAGE_SIZE / TSOH_STD_SIZE)
/* At most half the descriptors in the queue at any time will refer to
* a TSO header buffer, since they must always be followed by a
* payload descriptor referring to an skb.
*/
static unsigned int efx_tsoh_page_count(struct efx_tx_queue *tx_queue)
{
return DIV_ROUND_UP(tx_queue->ptr_mask + 1, 2 * TSOH_PER_PAGE);
}
int efx_probe_tx_queue(struct efx_tx_queue *tx_queue)
{
struct efx_nic *efx = tx_queue->efx;
unsigned int entries;
int rc;
/* Create the smallest power-of-two aligned ring */
entries = max(roundup_pow_of_two(efx->txq_entries), EFX_MIN_DMAQ_SIZE);
EFX_BUG_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE);
tx_queue->ptr_mask = entries - 1;
netif_dbg(efx, probe, efx->net_dev,
"creating TX queue %d size %#x mask %#x\n",
tx_queue->queue, efx->txq_entries, tx_queue->ptr_mask);
/* Allocate software ring */
tx_queue->buffer = kcalloc(entries, sizeof(*tx_queue->buffer),
GFP_KERNEL);
if (!tx_queue->buffer)
return -ENOMEM;
if (tx_queue->queue & EFX_TXQ_TYPE_OFFLOAD) {
tx_queue->tsoh_page =
kcalloc(efx_tsoh_page_count(tx_queue),
sizeof(tx_queue->tsoh_page[0]), GFP_KERNEL);
if (!tx_queue->tsoh_page) {
rc = -ENOMEM;
goto fail1;
}
}
/* Allocate hardware ring */
rc = efx_nic_probe_tx(tx_queue);
if (rc)
goto fail2;
return 0;
fail2:
kfree(tx_queue->tsoh_page);
tx_queue->tsoh_page = NULL;
fail1:
kfree(tx_queue->buffer);
tx_queue->buffer = NULL;
return rc;
}
void efx_init_tx_queue(struct efx_tx_queue *tx_queue)
{
netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev,
"initialising TX queue %d\n", tx_queue->queue);
tx_queue->insert_count = 0;
tx_queue->write_count = 0;
tx_queue->old_write_count = 0;
tx_queue->read_count = 0;
tx_queue->old_read_count = 0;
tx_queue->empty_read_count = 0 | EFX_EMPTY_COUNT_VALID;
/* Set up TX descriptor ring */
efx_nic_init_tx(tx_queue);
tx_queue->initialised = true;
}
void efx_release_tx_buffers(struct efx_tx_queue *tx_queue)
{
struct efx_tx_buffer *buffer;
if (!tx_queue->buffer)
return;
/* Free any buffers left in the ring */
while (tx_queue->read_count != tx_queue->write_count) {
unsigned int pkts_compl = 0, bytes_compl = 0;
buffer = &tx_queue->buffer[tx_queue->read_count & tx_queue->ptr_mask];
efx_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl);
++tx_queue->read_count;
}
netdev_tx_reset_queue(tx_queue->core_txq);
}
void efx_fini_tx_queue(struct efx_tx_queue *tx_queue)
{
if (!tx_queue->initialised)
return;
netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev,
"shutting down TX queue %d\n", tx_queue->queue);
tx_queue->initialised = false;
/* Flush TX queue, remove descriptor ring */
efx_nic_fini_tx(tx_queue);
efx_release_tx_buffers(tx_queue);
}
void efx_remove_tx_queue(struct efx_tx_queue *tx_queue)
{
int i;
if (!tx_queue->buffer)
return;
netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev,
"destroying TX queue %d\n", tx_queue->queue);
efx_nic_remove_tx(tx_queue);
if (tx_queue->tsoh_page) {
for (i = 0; i < efx_tsoh_page_count(tx_queue); i++)
efx_nic_free_buffer(tx_queue->efx,
&tx_queue->tsoh_page[i]);
kfree(tx_queue->tsoh_page);
tx_queue->tsoh_page = NULL;
}
kfree(tx_queue->buffer);
tx_queue->buffer = NULL;
}
/* Efx 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.
*/
/* Number of bytes inserted at the start of a TSO header buffer,
* similar to NET_IP_ALIGN.
*/
#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
#define TSOH_OFFSET 0
#else
#define TSOH_OFFSET NET_IP_ALIGN
#endif
#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
*
* 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 out_len;
unsigned seqnum;
unsigned ipv4_id;
unsigned packet_space;
/* Input position */
dma_addr_t dma_addr;
unsigned in_len;
unsigned unmap_len;
dma_addr_t unmap_addr;
unsigned short dma_flags;
__be16 protocol;
unsigned int ip_off;
unsigned int tcp_off;
unsigned header_len;
unsigned int ip_base_len;
};
/*
* 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);
if (likely(len <= TSOH_STD_SIZE - TSOH_OFFSET)) {
unsigned index =
(tx_queue->insert_count & tx_queue->ptr_mask) / 2;
struct efx_buffer *page_buf =
&tx_queue->tsoh_page[index / TSOH_PER_PAGE];
unsigned offset =
TSOH_STD_SIZE * (index % TSOH_PER_PAGE) + TSOH_OFFSET;
if (unlikely(!page_buf->addr) &&
efx_nic_alloc_buffer(tx_queue->efx, page_buf, PAGE_SIZE))
return NULL;
result = (u8 *)page_buf->addr + offset;
buffer->dma_addr = page_buf->dma_addr + offset;
buffer->flags = EFX_TX_BUF_CONT;
} else {
tx_queue->tso_long_headers++;
buffer->heap_buf = kmalloc(TSOH_OFFSET + len, GFP_ATOMIC);
if (unlikely(!buffer->heap_buf))
return NULL;
result = (u8 *)buffer->heap_buf + TSOH_OFFSET;
buffer->flags = EFX_TX_BUF_CONT | EFX_TX_BUF_HEAP;
}
buffer->len = len;
return result;
}
/**
* 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 len,
struct efx_tx_buffer **final_buffer)
{
struct efx_tx_buffer *buffer;
struct efx_nic *efx = tx_queue->efx;
unsigned dma_len, insert_ptr;
EFX_BUG_ON_PARANOID(len <= 0);
while (1) {
insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
buffer = &tx_queue->buffer[insert_ptr];
++tx_queue->insert_count;
EFX_BUG_ON_PARANOID(tx_queue->insert_count -
tx_queue->read_count >=
efx->txq_entries);
EFX_BUG_ON_PARANOID(buffer->len);
EFX_BUG_ON_PARANOID(buffer->unmap_len);
EFX_BUG_ON_PARANOID(buffer->flags);
buffer->dma_addr = dma_addr;
dma_len = efx_max_tx_len(efx, dma_addr);
/* If there is enough space to send then do so */
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;
}
/*
* 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->flags |= EFX_TX_BUF_MAP_SINGLE;
}
++tx_queue->insert_count;
return 0;
}
/* Remove buffers put into a tx_queue. None of the buffers must have
* an skb attached.
*/
static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
{
struct efx_tx_buffer *buffer;
/* Work backwards until we hit the original insert pointer value */
while (tx_queue->insert_count != tx_queue->write_count) {
--tx_queue->insert_count;
buffer = &tx_queue->buffer[tx_queue->insert_count &
tx_queue->ptr_mask];
efx_dequeue_buffer(tx_queue, buffer, NULL, NULL);
}
}
/* Parse the SKB header and initialise state. */
static void tso_start(struct tso_state *st, const struct sk_buff *skb)
{
st->ip_off = skb_network_header(skb) - skb->data;
st->tcp_off = skb_transport_header(skb) - skb->data;
st->header_len = st->tcp_off + (tcp_hdr(skb)->doff << 2u);
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 - st->header_len;
st->unmap_len = 0;
st->dma_flags = 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;
}
static int tso_get_head_fragment(struct tso_state *st, struct efx_nic *efx,
const struct sk_buff *skb)
{
int hl = st->header_len;
int len = skb_headlen(skb) - hl;
st->unmap_addr = dma_map_single(&efx->pci_dev->dev, skb->data + hl,
len, DMA_TO_DEVICE);
if (likely(!dma_mapping_error(&efx->pci_dev->dev, st->unmap_addr))) {
st->dma_flags = EFX_TX_BUF_MAP_SINGLE;
st->unmap_len = len;
st->in_len = len;
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->flags |= st->dma_flags;
st->unmap_len = 0;
}
st->dma_addr += n;
}
/**
* 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 =
&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;
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. */
st->packet_space = skb_shinfo(skb)->gso_size;
tsoh_th->fin = 0;
tsoh_th->psh = 0;
} 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;
}
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);
/* Linux leaves suitable gaps in the IP ID space for us to fill. */
tsoh_iph->id = htons(st->ipv4_id);
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;
++tx_queue->tso_packets;
return 0;
}
/**
* efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
* @tx_queue: Efx TX queue
* @skb: Socket buffer
*
* 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.
*/
static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
struct sk_buff *skb)
{
struct efx_nic *efx = tx_queue->efx;
int frag_i, rc;
struct tso_state state;
/* 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);
tso_start(&state, skb);
/* Assume that skb header area contains exactly the headers, and
* all payload is in the frag list.
*/
if (skb_headlen(skb) == state.header_len) {
/* 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 {
rc = tso_get_head_fragment(&state, efx, skb);
if (rc)
goto mem_err;
frag_i = -1;
}
if (tso_start_new_packet(tx_queue, skb, &state) < 0)
goto mem_err;
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;
}
netdev_tx_sent_queue(tx_queue->core_txq, skb->len);
/* Pass off to hardware */
efx_nic_push_buffers(tx_queue);
efx_tx_maybe_stop_queue(tx_queue);
tx_queue->tso_bursts++;
return NETDEV_TX_OK;
mem_err:
netif_err(efx, tx_err, efx->net_dev,
"Out of memory for TSO headers, or DMA mapping error\n");
dev_kfree_skb_any(skb);
/* 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);
}
efx_enqueue_unwind(tx_queue);
return NETDEV_TX_OK;
}
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