linux-stable/drivers/net/ethernet/sfc/tx.c
Jon Cooper daf37b556e sfc: PIO:Restrict to 64bit arch and use 64-bit writes.
Fixes:ee45fd92c739
("sfc: Use TX PIO for sufficiently small packets")

The linux net driver uses memcpy_toio() in order to copy into
the PIO buffers.
Even on a 64bit machine this causes 32bit accesses to a write-
combined memory region.
There are hardware limitations that mean that only 64bit
naturally aligned accesses are safe in all cases.
Due to being write-combined memory region two 32bit accesses
may be coalesced to form a 64bit non 64bit aligned access.
Solution was to open-code the memory copy routines using pointers
and to only enable PIO for x86_64 machines.

Not tested on platforms other than x86_64 because this patch
disables the PIO feature on other platforms.
Compile-tested on x86 to ensure that works.

The WARN_ON_ONCE() code in the previous version of this patch
has been moved into the internal sfc debug driver as the
assertion was unnecessary in the upstream kernel code.

This bug fix applies to v3.13 and v3.14 stable branches.

Signed-off-by: Shradha Shah <sshah@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-11 15:36:21 -07:00

1347 lines
37 KiB
C

/****************************************************************************
* Driver for Solarflare network controllers and boards
* Copyright 2005-2006 Fen Systems Ltd.
* Copyright 2005-2013 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/cache.h>
#include "net_driver.h"
#include "efx.h"
#include "io.h"
#include "nic.h"
#include "workarounds.h"
#include "ef10_regs.h"
#ifdef EFX_USE_PIO
#define EFX_PIOBUF_SIZE_MAX ER_DZ_TX_PIOBUF_SIZE
#define EFX_PIOBUF_SIZE_DEF ALIGN(256, L1_CACHE_BYTES)
unsigned int efx_piobuf_size __read_mostly = EFX_PIOBUF_SIZE_DEF;
#endif /* EFX_USE_PIO */
static inline unsigned int
efx_tx_queue_get_insert_index(const struct efx_tx_queue *tx_queue)
{
return tx_queue->insert_count & tx_queue->ptr_mask;
}
static inline struct efx_tx_buffer *
__efx_tx_queue_get_insert_buffer(const struct efx_tx_queue *tx_queue)
{
return &tx_queue->buffer[efx_tx_queue_get_insert_index(tx_queue)];
}
static inline struct efx_tx_buffer *
efx_tx_queue_get_insert_buffer(const struct efx_tx_queue *tx_queue)
{
struct efx_tx_buffer *buffer =
__efx_tx_queue_get_insert_buffer(tx_queue);
EFX_BUG_ON_PARANOID(buffer->len);
EFX_BUG_ON_PARANOID(buffer->flags);
EFX_BUG_ON_PARANOID(buffer->unmap_len);
return buffer;
}
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->dma_offset;
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,
* 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 */
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);
}
}
#ifdef EFX_USE_PIO
struct efx_short_copy_buffer {
int used;
u8 buf[L1_CACHE_BYTES];
};
/* Copy in explicit 64-bit writes. */
static void efx_memcpy_64(void __iomem *dest, void *src, size_t len)
{
u64 *src64 = src;
u64 __iomem *dest64 = dest;
size_t l64 = len / 8;
size_t i;
for (i = 0; i < l64; i++)
writeq(src64[i], &dest64[i]);
}
/* Copy to PIO, respecting that writes to PIO buffers must be dword aligned.
* Advances piobuf pointer. Leaves additional data in the copy buffer.
*/
static void efx_memcpy_toio_aligned(struct efx_nic *efx, u8 __iomem **piobuf,
u8 *data, int len,
struct efx_short_copy_buffer *copy_buf)
{
int block_len = len & ~(sizeof(copy_buf->buf) - 1);
efx_memcpy_64(*piobuf, data, block_len);
*piobuf += block_len;
len -= block_len;
if (len) {
data += block_len;
BUG_ON(copy_buf->used);
BUG_ON(len > sizeof(copy_buf->buf));
memcpy(copy_buf->buf, data, len);
copy_buf->used = len;
}
}
/* Copy to PIO, respecting dword alignment, popping data from copy buffer first.
* Advances piobuf pointer. Leaves additional data in the copy buffer.
*/
static void efx_memcpy_toio_aligned_cb(struct efx_nic *efx, u8 __iomem **piobuf,
u8 *data, int len,
struct efx_short_copy_buffer *copy_buf)
{
if (copy_buf->used) {
/* if the copy buffer is partially full, fill it up and write */
int copy_to_buf =
min_t(int, sizeof(copy_buf->buf) - copy_buf->used, len);
memcpy(copy_buf->buf + copy_buf->used, data, copy_to_buf);
copy_buf->used += copy_to_buf;
/* if we didn't fill it up then we're done for now */
if (copy_buf->used < sizeof(copy_buf->buf))
return;
efx_memcpy_64(*piobuf, copy_buf->buf, sizeof(copy_buf->buf));
*piobuf += sizeof(copy_buf->buf);
data += copy_to_buf;
len -= copy_to_buf;
copy_buf->used = 0;
}
efx_memcpy_toio_aligned(efx, piobuf, data, len, copy_buf);
}
static void efx_flush_copy_buffer(struct efx_nic *efx, u8 __iomem *piobuf,
struct efx_short_copy_buffer *copy_buf)
{
/* if there's anything in it, write the whole buffer, including junk */
if (copy_buf->used)
efx_memcpy_64(piobuf, copy_buf->buf, sizeof(copy_buf->buf));
}
/* Traverse skb structure and copy fragments in to PIO buffer.
* Advances piobuf pointer.
*/
static void efx_skb_copy_bits_to_pio(struct efx_nic *efx, struct sk_buff *skb,
u8 __iomem **piobuf,
struct efx_short_copy_buffer *copy_buf)
{
int i;
efx_memcpy_toio_aligned(efx, piobuf, skb->data, skb_headlen(skb),
copy_buf);
for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
skb_frag_t *f = &skb_shinfo(skb)->frags[i];
u8 *vaddr;
vaddr = kmap_atomic(skb_frag_page(f));
efx_memcpy_toio_aligned_cb(efx, piobuf, vaddr + f->page_offset,
skb_frag_size(f), copy_buf);
kunmap_atomic(vaddr);
}
EFX_BUG_ON_PARANOID(skb_shinfo(skb)->frag_list);
}
static struct efx_tx_buffer *
efx_enqueue_skb_pio(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
{
struct efx_tx_buffer *buffer =
efx_tx_queue_get_insert_buffer(tx_queue);
u8 __iomem *piobuf = tx_queue->piobuf;
/* Copy to PIO buffer. Ensure the writes are padded to the end
* of a cache line, as this is required for write-combining to be
* effective on at least x86.
*/
if (skb_shinfo(skb)->nr_frags) {
/* The size of the copy buffer will ensure all writes
* are the size of a cache line.
*/
struct efx_short_copy_buffer copy_buf;
copy_buf.used = 0;
efx_skb_copy_bits_to_pio(tx_queue->efx, skb,
&piobuf, &copy_buf);
efx_flush_copy_buffer(tx_queue->efx, piobuf, &copy_buf);
} else {
/* Pad the write to the size of a cache line.
* We can do this because we know the skb_shared_info sruct is
* after the source, and the destination buffer is big enough.
*/
BUILD_BUG_ON(L1_CACHE_BYTES >
SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
efx_memcpy_64(tx_queue->piobuf, skb->data,
ALIGN(skb->len, L1_CACHE_BYTES));
}
EFX_POPULATE_QWORD_5(buffer->option,
ESF_DZ_TX_DESC_IS_OPT, 1,
ESF_DZ_TX_OPTION_TYPE, ESE_DZ_TX_OPTION_DESC_PIO,
ESF_DZ_TX_PIO_CONT, 0,
ESF_DZ_TX_PIO_BYTE_CNT, skb->len,
ESF_DZ_TX_PIO_BUF_ADDR,
tx_queue->piobuf_offset);
++tx_queue->pio_packets;
++tx_queue->insert_count;
return buffer;
}
#endif /* EFX_USE_PIO */
/*
* 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;
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;
}
/* Consider using PIO for short packets */
#ifdef EFX_USE_PIO
if (skb->len <= efx_piobuf_size && tx_queue->piobuf &&
efx_nic_tx_is_empty(tx_queue) &&
efx_nic_tx_is_empty(efx_tx_queue_partner(tx_queue))) {
buffer = efx_enqueue_skb_pio(tx_queue, skb);
dma_flags = EFX_TX_BUF_OPTION;
goto finish_packet;
}
#endif
/* 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 {
buffer = efx_tx_queue_get_insert_buffer(tx_queue);
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;
buffer->dma_offset = buffer->dma_addr - unmap_addr;
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 */
#ifdef EFX_USE_PIO
finish_packet:
#endif
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;
buffer = __efx_tx_queue_get_insert_buffer(tx_queue);
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 (!(buffer->flags & EFX_TX_BUF_OPTION) &&
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);
if (pkts_compl > 1)
++tx_queue->merge_events;
/* 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_fini_tx_queue(struct efx_tx_queue *tx_queue)
{
struct efx_tx_buffer *buffer;
netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev,
"shutting down TX queue %d\n", tx_queue->queue);
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_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.
*/
#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 out_len;
unsigned seqnum;
u16 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;
dma_addr_t header_dma_addr;
unsigned int header_unmap_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 - NET_IP_ALIGN)) {
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) + NET_IP_ALIGN;
if (unlikely(!page_buf->addr) &&
efx_nic_alloc_buffer(tx_queue->efx, page_buf, PAGE_SIZE,
GFP_ATOMIC))
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(NET_IP_ALIGN + len, GFP_ATOMIC);
if (unlikely(!buffer->heap_buf))
return NULL;
result = (u8 *)buffer->heap_buf + NET_IP_ALIGN;
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;
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 >=
efx->txq_entries);
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->dma_offset = 0;
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 = __efx_tx_queue_get_insert_buffer(tx_queue);
efx_dequeue_buffer(tx_queue, buffer, NULL, NULL);
}
}
/* Parse the SKB header and initialise state. */
static int tso_start(struct tso_state *st, struct efx_nic *efx,
const struct sk_buff *skb)
{
bool use_opt_desc = 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;
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;
}
/**
* 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_clear;
if (!is_last) {
st->packet_space = skb_shinfo(skb)->gso_size;
tcp_flags_clear = 0x09; /* mask out FIN and PSH */
} else {
st->packet_space = st->out_len;
tcp_flags_clear = 0x00;
}
if (!st->header_unmap_len) {
/* Allocate and insert a DMA-mapped header buffer. */
struct tcphdr *tsoh_th;
unsigned 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)[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 {
/* 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;
/* 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;
++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);
rc = tso_start(&state, efx, 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;
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);
}
/* 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;
}