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OpenCloudOS-Kernel/drivers/net/sfc/rx.c

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/****************************************************************************
* Driver for Solarflare Solarstorm network controllers and boards
* Copyright 2005-2006 Fen Systems Ltd.
* Copyright 2005-2008 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/socket.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <net/ip.h>
#include <net/checksum.h>
#include "net_driver.h"
#include "rx.h"
#include "efx.h"
#include "falcon.h"
#include "selftest.h"
#include "workarounds.h"
/* Number of RX descriptors pushed at once. */
#define EFX_RX_BATCH 8
/* Size of buffer allocated for skb header area. */
#define EFX_SKB_HEADERS 64u
/*
* rx_alloc_method - RX buffer allocation method
*
* This driver supports two methods for allocating and using RX buffers:
* each RX buffer may be backed by an skb or by an order-n page.
*
* When LRO is in use then the second method has a lower overhead,
* since we don't have to allocate then free skbs on reassembled frames.
*
* Values:
* - RX_ALLOC_METHOD_AUTO = 0
* - RX_ALLOC_METHOD_SKB = 1
* - RX_ALLOC_METHOD_PAGE = 2
*
* The heuristic for %RX_ALLOC_METHOD_AUTO is a simple hysteresis count
* controlled by the parameters below.
*
* - Since pushing and popping descriptors are separated by the rx_queue
* size, so the watermarks should be ~rxd_size.
* - The performance win by using page-based allocation for LRO is less
* than the performance hit of using page-based allocation of non-LRO,
* so the watermarks should reflect this.
*
* Per channel we maintain a single variable, updated by each channel:
*
* rx_alloc_level += (lro_performed ? RX_ALLOC_FACTOR_LRO :
* RX_ALLOC_FACTOR_SKB)
* Per NAPI poll interval, we constrain rx_alloc_level to 0..MAX (which
* limits the hysteresis), and update the allocation strategy:
*
* rx_alloc_method = (rx_alloc_level > RX_ALLOC_LEVEL_LRO ?
* RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB)
*/
static int rx_alloc_method = RX_ALLOC_METHOD_PAGE;
#define RX_ALLOC_LEVEL_LRO 0x2000
#define RX_ALLOC_LEVEL_MAX 0x3000
#define RX_ALLOC_FACTOR_LRO 1
#define RX_ALLOC_FACTOR_SKB (-2)
/* This is the percentage fill level below which new RX descriptors
* will be added to the RX descriptor ring.
*/
static unsigned int rx_refill_threshold = 90;
/* This is the percentage fill level to which an RX queue will be refilled
* when the "RX refill threshold" is reached.
*/
static unsigned int rx_refill_limit = 95;
/*
* RX maximum head room required.
*
* This must be at least 1 to prevent overflow and at least 2 to allow
* pipelined receives.
*/
#define EFX_RXD_HEAD_ROOM 2
static inline unsigned int efx_rx_buf_offset(struct efx_rx_buffer *buf)
{
/* Offset is always within one page, so we don't need to consider
* the page order.
*/
return (__force unsigned long) buf->data & (PAGE_SIZE - 1);
}
static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)
{
return PAGE_SIZE << efx->rx_buffer_order;
}
/**
* efx_init_rx_buffer_skb - create new RX buffer using skb-based allocation
*
* @rx_queue: Efx RX queue
* @rx_buf: RX buffer structure to populate
*
* This allocates memory for a new receive buffer, maps it for DMA,
* and populates a struct efx_rx_buffer with the relevant
* information. Return a negative error code or 0 on success.
*/
static int efx_init_rx_buffer_skb(struct efx_rx_queue *rx_queue,
struct efx_rx_buffer *rx_buf)
{
struct efx_nic *efx = rx_queue->efx;
struct net_device *net_dev = efx->net_dev;
int skb_len = efx->rx_buffer_len;
rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);
if (unlikely(!rx_buf->skb))
return -ENOMEM;
/* Adjust the SKB for padding and checksum */
skb_reserve(rx_buf->skb, NET_IP_ALIGN);
rx_buf->len = skb_len - NET_IP_ALIGN;
rx_buf->data = (char *)rx_buf->skb->data;
rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY;
rx_buf->dma_addr = pci_map_single(efx->pci_dev,
rx_buf->data, rx_buf->len,
PCI_DMA_FROMDEVICE);
if (unlikely(pci_dma_mapping_error(efx->pci_dev, rx_buf->dma_addr))) {
dev_kfree_skb_any(rx_buf->skb);
rx_buf->skb = NULL;
return -EIO;
}
return 0;
}
/**
* efx_init_rx_buffer_page - create new RX buffer using page-based allocation
*
* @rx_queue: Efx RX queue
* @rx_buf: RX buffer structure to populate
*
* This allocates memory for a new receive buffer, maps it for DMA,
* and populates a struct efx_rx_buffer with the relevant
* information. Return a negative error code or 0 on success.
*/
static int efx_init_rx_buffer_page(struct efx_rx_queue *rx_queue,
struct efx_rx_buffer *rx_buf)
{
struct efx_nic *efx = rx_queue->efx;
int bytes, space, offset;
bytes = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
/* If there is space left in the previously allocated page,
* then use it. Otherwise allocate a new one */
rx_buf->page = rx_queue->buf_page;
if (rx_buf->page == NULL) {
dma_addr_t dma_addr;
rx_buf->page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
efx->rx_buffer_order);
if (unlikely(rx_buf->page == NULL))
return -ENOMEM;
dma_addr = pci_map_page(efx->pci_dev, rx_buf->page,
0, efx_rx_buf_size(efx),
PCI_DMA_FROMDEVICE);
if (unlikely(pci_dma_mapping_error(efx->pci_dev, dma_addr))) {
__free_pages(rx_buf->page, efx->rx_buffer_order);
rx_buf->page = NULL;
return -EIO;
}
rx_queue->buf_page = rx_buf->page;
rx_queue->buf_dma_addr = dma_addr;
rx_queue->buf_data = (page_address(rx_buf->page) +
EFX_PAGE_IP_ALIGN);
}
rx_buf->len = bytes;
rx_buf->data = rx_queue->buf_data;
offset = efx_rx_buf_offset(rx_buf);
rx_buf->dma_addr = rx_queue->buf_dma_addr + offset;
/* Try to pack multiple buffers per page */
if (efx->rx_buffer_order == 0) {
/* The next buffer starts on the next 512 byte boundary */
rx_queue->buf_data += ((bytes + 0x1ff) & ~0x1ff);
offset += ((bytes + 0x1ff) & ~0x1ff);
space = efx_rx_buf_size(efx) - offset;
if (space >= bytes) {
/* Refs dropped on kernel releasing each skb */
get_page(rx_queue->buf_page);
goto out;
}
}
/* This is the final RX buffer for this page, so mark it for
* unmapping */
rx_queue->buf_page = NULL;
rx_buf->unmap_addr = rx_queue->buf_dma_addr;
out:
return 0;
}
/* This allocates memory for a new receive buffer, maps it for DMA,
* and populates a struct efx_rx_buffer with the relevant
* information.
*/
static int efx_init_rx_buffer(struct efx_rx_queue *rx_queue,
struct efx_rx_buffer *new_rx_buf)
{
int rc = 0;
if (rx_queue->channel->rx_alloc_push_pages) {
new_rx_buf->skb = NULL;
rc = efx_init_rx_buffer_page(rx_queue, new_rx_buf);
rx_queue->alloc_page_count++;
} else {
new_rx_buf->page = NULL;
rc = efx_init_rx_buffer_skb(rx_queue, new_rx_buf);
rx_queue->alloc_skb_count++;
}
if (unlikely(rc < 0))
EFX_LOG_RL(rx_queue->efx, "%s RXQ[%d] =%d\n", __func__,
rx_queue->queue, rc);
return rc;
}
static void efx_unmap_rx_buffer(struct efx_nic *efx,
struct efx_rx_buffer *rx_buf)
{
if (rx_buf->page) {
EFX_BUG_ON_PARANOID(rx_buf->skb);
if (rx_buf->unmap_addr) {
pci_unmap_page(efx->pci_dev, rx_buf->unmap_addr,
efx_rx_buf_size(efx),
PCI_DMA_FROMDEVICE);
rx_buf->unmap_addr = 0;
}
} else if (likely(rx_buf->skb)) {
pci_unmap_single(efx->pci_dev, rx_buf->dma_addr,
rx_buf->len, PCI_DMA_FROMDEVICE);
}
}
static void efx_free_rx_buffer(struct efx_nic *efx,
struct efx_rx_buffer *rx_buf)
{
if (rx_buf->page) {
__free_pages(rx_buf->page, efx->rx_buffer_order);
rx_buf->page = NULL;
} else if (likely(rx_buf->skb)) {
dev_kfree_skb_any(rx_buf->skb);
rx_buf->skb = NULL;
}
}
static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
struct efx_rx_buffer *rx_buf)
{
efx_unmap_rx_buffer(rx_queue->efx, rx_buf);
efx_free_rx_buffer(rx_queue->efx, rx_buf);
}
/**
* efx_fast_push_rx_descriptors - push new RX descriptors quickly
* @rx_queue: RX descriptor queue
* @retry: Recheck the fill level
* This will aim to fill the RX descriptor queue up to
* @rx_queue->@fast_fill_limit. If there is insufficient atomic
* memory to do so, the caller should retry.
*/
static int __efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue,
int retry)
{
struct efx_rx_buffer *rx_buf;
unsigned fill_level, index;
int i, space, rc = 0;
/* Calculate current fill level. Do this outside the lock,
* because most of the time we'll end up not wanting to do the
* fill anyway.
*/
fill_level = (rx_queue->added_count - rx_queue->removed_count);
EFX_BUG_ON_PARANOID(fill_level >
rx_queue->efx->type->rxd_ring_mask + 1);
/* Don't fill if we don't need to */
if (fill_level >= rx_queue->fast_fill_trigger)
return 0;
/* Record minimum fill level */
if (unlikely(fill_level < rx_queue->min_fill)) {
if (fill_level)
rx_queue->min_fill = fill_level;
}
/* Acquire RX add lock. If this lock is contended, then a fast
* fill must already be in progress (e.g. in the refill
* tasklet), so we don't need to do anything
*/
if (!spin_trylock_bh(&rx_queue->add_lock))
return -1;
retry:
/* Recalculate current fill level now that we have the lock */
fill_level = (rx_queue->added_count - rx_queue->removed_count);
EFX_BUG_ON_PARANOID(fill_level >
rx_queue->efx->type->rxd_ring_mask + 1);
space = rx_queue->fast_fill_limit - fill_level;
if (space < EFX_RX_BATCH)
goto out_unlock;
EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from"
" level %d to level %d using %s allocation\n",
rx_queue->queue, fill_level, rx_queue->fast_fill_limit,
rx_queue->channel->rx_alloc_push_pages ? "page" : "skb");
do {
for (i = 0; i < EFX_RX_BATCH; ++i) {
index = (rx_queue->added_count &
rx_queue->efx->type->rxd_ring_mask);
rx_buf = efx_rx_buffer(rx_queue, index);
rc = efx_init_rx_buffer(rx_queue, rx_buf);
if (unlikely(rc))
goto out;
++rx_queue->added_count;
}
} while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH);
EFX_TRACE(rx_queue->efx, "RX queue %d fast-filled descriptor ring "
"to level %d\n", rx_queue->queue,
rx_queue->added_count - rx_queue->removed_count);
out:
/* Send write pointer to card. */
falcon_notify_rx_desc(rx_queue);
/* If the fast fill is running inside from the refill tasklet, then
* for SMP systems it may be running on a different CPU to
* RX event processing, which means that the fill level may now be
* out of date. */
if (unlikely(retry && (rc == 0)))
goto retry;
out_unlock:
spin_unlock_bh(&rx_queue->add_lock);
return rc;
}
/**
* efx_fast_push_rx_descriptors - push new RX descriptors quickly
* @rx_queue: RX descriptor queue
*
* This will aim to fill the RX descriptor queue up to
* @rx_queue->@fast_fill_limit. If there is insufficient memory to do so,
* it will schedule a work item to immediately continue the fast fill
*/
void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
{
int rc;
rc = __efx_fast_push_rx_descriptors(rx_queue, 0);
if (unlikely(rc)) {
/* Schedule the work item to run immediately. The hope is
* that work is immediately pending to free some memory
* (e.g. an RX event or TX completion)
*/
efx_schedule_slow_fill(rx_queue, 0);
}
}
void efx_rx_work(struct work_struct *data)
{
struct efx_rx_queue *rx_queue;
int rc;
rx_queue = container_of(data, struct efx_rx_queue, work.work);
if (unlikely(!rx_queue->channel->enabled))
return;
EFX_TRACE(rx_queue->efx, "RX queue %d worker thread executing on CPU "
"%d\n", rx_queue->queue, raw_smp_processor_id());
++rx_queue->slow_fill_count;
/* Push new RX descriptors, allowing at least 1 jiffy for
* the kernel to free some more memory. */
rc = __efx_fast_push_rx_descriptors(rx_queue, 1);
if (rc)
efx_schedule_slow_fill(rx_queue, 1);
}
static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
struct efx_rx_buffer *rx_buf,
int len, bool *discard,
bool *leak_packet)
{
struct efx_nic *efx = rx_queue->efx;
unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;
if (likely(len <= max_len))
return;
/* The packet must be discarded, but this is only a fatal error
* if the caller indicated it was
*/
*discard = true;
if ((len > rx_buf->len) && EFX_WORKAROUND_8071(efx)) {
EFX_ERR_RL(efx, " RX queue %d seriously overlength "
"RX event (0x%x > 0x%x+0x%x). Leaking\n",
rx_queue->queue, len, max_len,
efx->type->rx_buffer_padding);
/* If this buffer was skb-allocated, then the meta
* data at the end of the skb will be trashed. So
* we have no choice but to leak the fragment.
*/
*leak_packet = (rx_buf->skb != NULL);
efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY);
} else {
EFX_ERR_RL(efx, " RX queue %d overlength RX event "
"(0x%x > 0x%x)\n", rx_queue->queue, len, max_len);
}
rx_queue->channel->n_rx_overlength++;
}
/* Pass a received packet up through the generic LRO stack
*
* Handles driverlink veto, and passes the fragment up via
* the appropriate LRO method
*/
static void efx_rx_packet_lro(struct efx_channel *channel,
struct efx_rx_buffer *rx_buf)
{
struct napi_struct *napi = &channel->napi_str;
/* Pass the skb/page into the LRO engine */
if (rx_buf->page) {
struct napi_gro_fraginfo info;
info.frags[0].page = rx_buf->page;
info.frags[0].page_offset = efx_rx_buf_offset(rx_buf);
info.frags[0].size = rx_buf->len;
info.nr_frags = 1;
info.ip_summed = CHECKSUM_UNNECESSARY;
info.len = rx_buf->len;
napi_gro_frags(napi, &info);
EFX_BUG_ON_PARANOID(rx_buf->skb);
rx_buf->page = NULL;
} else {
EFX_BUG_ON_PARANOID(!rx_buf->skb);
napi_gro_receive(napi, rx_buf->skb);
rx_buf->skb = NULL;
}
}
void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
unsigned int len, bool checksummed, bool discard)
{
struct efx_nic *efx = rx_queue->efx;
struct efx_rx_buffer *rx_buf;
bool leak_packet = false;
rx_buf = efx_rx_buffer(rx_queue, index);
EFX_BUG_ON_PARANOID(!rx_buf->data);
EFX_BUG_ON_PARANOID(rx_buf->skb && rx_buf->page);
EFX_BUG_ON_PARANOID(!(rx_buf->skb || rx_buf->page));
/* This allows the refill path to post another buffer.
* EFX_RXD_HEAD_ROOM ensures that the slot we are using
* isn't overwritten yet.
*/
rx_queue->removed_count++;
/* Validate the length encoded in the event vs the descriptor pushed */
efx_rx_packet__check_len(rx_queue, rx_buf, len,
&discard, &leak_packet);
EFX_TRACE(efx, "RX queue %d received id %x at %llx+%x %s%s\n",
rx_queue->queue, index,
(unsigned long long)rx_buf->dma_addr, len,
(checksummed ? " [SUMMED]" : ""),
(discard ? " [DISCARD]" : ""));
/* Discard packet, if instructed to do so */
if (unlikely(discard)) {
if (unlikely(leak_packet))
rx_queue->channel->n_skbuff_leaks++;
else
/* We haven't called efx_unmap_rx_buffer yet,
* so fini the entire rx_buffer here */
efx_fini_rx_buffer(rx_queue, rx_buf);
return;
}
/* Release card resources - assumes all RX buffers consumed in-order
* per RX queue
*/
efx_unmap_rx_buffer(efx, rx_buf);
/* Prefetch nice and early so data will (hopefully) be in cache by
* the time we look at it.
*/
prefetch(rx_buf->data);
/* Pipeline receives so that we give time for packet headers to be
* prefetched into cache.
*/
rx_buf->len = len;
if (rx_queue->channel->rx_pkt)
__efx_rx_packet(rx_queue->channel,
rx_queue->channel->rx_pkt,
rx_queue->channel->rx_pkt_csummed);
rx_queue->channel->rx_pkt = rx_buf;
rx_queue->channel->rx_pkt_csummed = checksummed;
}
/* Handle a received packet. Second half: Touches packet payload. */
void __efx_rx_packet(struct efx_channel *channel,
struct efx_rx_buffer *rx_buf, bool checksummed)
{
struct efx_nic *efx = channel->efx;
struct sk_buff *skb;
/* If we're in loopback test, then pass the packet directly to the
* loopback layer, and free the rx_buf here
*/
if (unlikely(efx->loopback_selftest)) {
efx_loopback_rx_packet(efx, rx_buf->data, rx_buf->len);
efx_free_rx_buffer(efx, rx_buf);
goto done;
}
if (rx_buf->skb) {
prefetch(skb_shinfo(rx_buf->skb));
skb_put(rx_buf->skb, rx_buf->len);
/* Move past the ethernet header. rx_buf->data still points
* at the ethernet header */
rx_buf->skb->protocol = eth_type_trans(rx_buf->skb,
efx->net_dev);
}
if (likely(checksummed || rx_buf->page)) {
efx_rx_packet_lro(channel, rx_buf);
goto done;
}
/* We now own the SKB */
skb = rx_buf->skb;
rx_buf->skb = NULL;
EFX_BUG_ON_PARANOID(rx_buf->page);
EFX_BUG_ON_PARANOID(rx_buf->skb);
EFX_BUG_ON_PARANOID(!skb);
/* Set the SKB flags */
skb->ip_summed = CHECKSUM_NONE;
skb_record_rx_queue(skb, channel->channel);
/* Pass the packet up */
netif_receive_skb(skb);
/* Update allocation strategy method */
channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
done:
;
}
void efx_rx_strategy(struct efx_channel *channel)
{
enum efx_rx_alloc_method method = rx_alloc_method;
/* Only makes sense to use page based allocation if LRO is enabled */
if (!(channel->efx->net_dev->features & NETIF_F_GRO)) {
method = RX_ALLOC_METHOD_SKB;
} else if (method == RX_ALLOC_METHOD_AUTO) {
/* Constrain the rx_alloc_level */
if (channel->rx_alloc_level < 0)
channel->rx_alloc_level = 0;
else if (channel->rx_alloc_level > RX_ALLOC_LEVEL_MAX)
channel->rx_alloc_level = RX_ALLOC_LEVEL_MAX;
/* Decide on the allocation method */
method = ((channel->rx_alloc_level > RX_ALLOC_LEVEL_LRO) ?
RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB);
}
/* Push the option */
channel->rx_alloc_push_pages = (method == RX_ALLOC_METHOD_PAGE);
}
int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
{
struct efx_nic *efx = rx_queue->efx;
unsigned int rxq_size;
int rc;
EFX_LOG(efx, "creating RX queue %d\n", rx_queue->queue);
/* Allocate RX buffers */
rxq_size = (efx->type->rxd_ring_mask + 1) * sizeof(*rx_queue->buffer);
rx_queue->buffer = kzalloc(rxq_size, GFP_KERNEL);
if (!rx_queue->buffer)
return -ENOMEM;
rc = falcon_probe_rx(rx_queue);
if (rc) {
kfree(rx_queue->buffer);
rx_queue->buffer = NULL;
}
return rc;
}
void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
{
struct efx_nic *efx = rx_queue->efx;
unsigned int max_fill, trigger, limit;
EFX_LOG(rx_queue->efx, "initialising RX queue %d\n", rx_queue->queue);
/* Initialise ptr fields */
rx_queue->added_count = 0;
rx_queue->notified_count = 0;
rx_queue->removed_count = 0;
rx_queue->min_fill = -1U;
rx_queue->min_overfill = -1U;
/* Initialise limit fields */
max_fill = efx->type->rxd_ring_mask + 1 - EFX_RXD_HEAD_ROOM;
trigger = max_fill * min(rx_refill_threshold, 100U) / 100U;
limit = max_fill * min(rx_refill_limit, 100U) / 100U;
rx_queue->max_fill = max_fill;
rx_queue->fast_fill_trigger = trigger;
rx_queue->fast_fill_limit = limit;
/* Set up RX descriptor ring */
falcon_init_rx(rx_queue);
}
void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
{
int i;
struct efx_rx_buffer *rx_buf;
EFX_LOG(rx_queue->efx, "shutting down RX queue %d\n", rx_queue->queue);
falcon_fini_rx(rx_queue);
/* Release RX buffers NB start at index 0 not current HW ptr */
if (rx_queue->buffer) {
for (i = 0; i <= rx_queue->efx->type->rxd_ring_mask; i++) {
rx_buf = efx_rx_buffer(rx_queue, i);
efx_fini_rx_buffer(rx_queue, rx_buf);
}
}
/* For a page that is part-way through splitting into RX buffers */
if (rx_queue->buf_page != NULL) {
pci_unmap_page(rx_queue->efx->pci_dev, rx_queue->buf_dma_addr,
efx_rx_buf_size(rx_queue->efx),
PCI_DMA_FROMDEVICE);
__free_pages(rx_queue->buf_page,
rx_queue->efx->rx_buffer_order);
rx_queue->buf_page = NULL;
}
}
void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)
{
EFX_LOG(rx_queue->efx, "destroying RX queue %d\n", rx_queue->queue);
falcon_remove_rx(rx_queue);
kfree(rx_queue->buffer);
rx_queue->buffer = NULL;
}
module_param(rx_alloc_method, int, 0644);
MODULE_PARM_DESC(rx_alloc_method, "Allocation method used for RX buffers");
module_param(rx_refill_threshold, uint, 0444);
MODULE_PARM_DESC(rx_refill_threshold,
"RX descriptor ring fast/slow fill threshold (%)");
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