/*******************************************************************************
*
* Intel Ethernet Controller XL710 Family Linux Virtual Function Driver
* Copyright(c) 2013 - 2016 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see .
*
* The full GNU General Public License is included in this distribution in
* the file called "COPYING".
*
* Contact Information:
* e1000-devel Mailing List
* Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
*
******************************************************************************/
#include
#include
#include "i40evf.h"
#include "i40e_prototype.h"
static inline __le64 build_ctob(u32 td_cmd, u32 td_offset, unsigned int size,
u32 td_tag)
{
return cpu_to_le64(I40E_TX_DESC_DTYPE_DATA |
((u64)td_cmd << I40E_TXD_QW1_CMD_SHIFT) |
((u64)td_offset << I40E_TXD_QW1_OFFSET_SHIFT) |
((u64)size << I40E_TXD_QW1_TX_BUF_SZ_SHIFT) |
((u64)td_tag << I40E_TXD_QW1_L2TAG1_SHIFT));
}
#define I40E_TXD_CMD (I40E_TX_DESC_CMD_EOP | I40E_TX_DESC_CMD_RS)
/**
* i40e_unmap_and_free_tx_resource - Release a Tx buffer
* @ring: the ring that owns the buffer
* @tx_buffer: the buffer to free
**/
static void i40e_unmap_and_free_tx_resource(struct i40e_ring *ring,
struct i40e_tx_buffer *tx_buffer)
{
if (tx_buffer->skb) {
if (tx_buffer->tx_flags & I40E_TX_FLAGS_FD_SB)
kfree(tx_buffer->raw_buf);
else
dev_kfree_skb_any(tx_buffer->skb);
if (dma_unmap_len(tx_buffer, len))
dma_unmap_single(ring->dev,
dma_unmap_addr(tx_buffer, dma),
dma_unmap_len(tx_buffer, len),
DMA_TO_DEVICE);
} else if (dma_unmap_len(tx_buffer, len)) {
dma_unmap_page(ring->dev,
dma_unmap_addr(tx_buffer, dma),
dma_unmap_len(tx_buffer, len),
DMA_TO_DEVICE);
}
tx_buffer->next_to_watch = NULL;
tx_buffer->skb = NULL;
dma_unmap_len_set(tx_buffer, len, 0);
/* tx_buffer must be completely set up in the transmit path */
}
/**
* i40evf_clean_tx_ring - Free any empty Tx buffers
* @tx_ring: ring to be cleaned
**/
void i40evf_clean_tx_ring(struct i40e_ring *tx_ring)
{
unsigned long bi_size;
u16 i;
/* ring already cleared, nothing to do */
if (!tx_ring->tx_bi)
return;
/* Free all the Tx ring sk_buffs */
for (i = 0; i < tx_ring->count; i++)
i40e_unmap_and_free_tx_resource(tx_ring, &tx_ring->tx_bi[i]);
bi_size = sizeof(struct i40e_tx_buffer) * tx_ring->count;
memset(tx_ring->tx_bi, 0, bi_size);
/* Zero out the descriptor ring */
memset(tx_ring->desc, 0, tx_ring->size);
tx_ring->next_to_use = 0;
tx_ring->next_to_clean = 0;
if (!tx_ring->netdev)
return;
/* cleanup Tx queue statistics */
netdev_tx_reset_queue(txring_txq(tx_ring));
}
/**
* i40evf_free_tx_resources - Free Tx resources per queue
* @tx_ring: Tx descriptor ring for a specific queue
*
* Free all transmit software resources
**/
void i40evf_free_tx_resources(struct i40e_ring *tx_ring)
{
i40evf_clean_tx_ring(tx_ring);
kfree(tx_ring->tx_bi);
tx_ring->tx_bi = NULL;
if (tx_ring->desc) {
dma_free_coherent(tx_ring->dev, tx_ring->size,
tx_ring->desc, tx_ring->dma);
tx_ring->desc = NULL;
}
}
/**
* i40evf_get_tx_pending - how many Tx descriptors not processed
* @tx_ring: the ring of descriptors
* @in_sw: is tx_pending being checked in SW or HW
*
* Since there is no access to the ring head register
* in XL710, we need to use our local copies
**/
u32 i40evf_get_tx_pending(struct i40e_ring *ring, bool in_sw)
{
u32 head, tail;
if (!in_sw)
head = i40e_get_head(ring);
else
head = ring->next_to_clean;
tail = readl(ring->tail);
if (head != tail)
return (head < tail) ?
tail - head : (tail + ring->count - head);
return 0;
}
#define WB_STRIDE 0x3
/**
* i40e_clean_tx_irq - Reclaim resources after transmit completes
* @vsi: the VSI we care about
* @tx_ring: Tx ring to clean
* @napi_budget: Used to determine if we are in netpoll
*
* Returns true if there's any budget left (e.g. the clean is finished)
**/
static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
struct i40e_ring *tx_ring, int napi_budget)
{
u16 i = tx_ring->next_to_clean;
struct i40e_tx_buffer *tx_buf;
struct i40e_tx_desc *tx_head;
struct i40e_tx_desc *tx_desc;
unsigned int total_bytes = 0, total_packets = 0;
unsigned int budget = vsi->work_limit;
tx_buf = &tx_ring->tx_bi[i];
tx_desc = I40E_TX_DESC(tx_ring, i);
i -= tx_ring->count;
tx_head = I40E_TX_DESC(tx_ring, i40e_get_head(tx_ring));
do {
struct i40e_tx_desc *eop_desc = tx_buf->next_to_watch;
/* if next_to_watch is not set then there is no work pending */
if (!eop_desc)
break;
/* prevent any other reads prior to eop_desc */
read_barrier_depends();
/* we have caught up to head, no work left to do */
if (tx_head == tx_desc)
break;
/* clear next_to_watch to prevent false hangs */
tx_buf->next_to_watch = NULL;
/* update the statistics for this packet */
total_bytes += tx_buf->bytecount;
total_packets += tx_buf->gso_segs;
/* free the skb */
napi_consume_skb(tx_buf->skb, napi_budget);
/* unmap skb header data */
dma_unmap_single(tx_ring->dev,
dma_unmap_addr(tx_buf, dma),
dma_unmap_len(tx_buf, len),
DMA_TO_DEVICE);
/* clear tx_buffer data */
tx_buf->skb = NULL;
dma_unmap_len_set(tx_buf, len, 0);
/* unmap remaining buffers */
while (tx_desc != eop_desc) {
tx_buf++;
tx_desc++;
i++;
if (unlikely(!i)) {
i -= tx_ring->count;
tx_buf = tx_ring->tx_bi;
tx_desc = I40E_TX_DESC(tx_ring, 0);
}
/* unmap any remaining paged data */
if (dma_unmap_len(tx_buf, len)) {
dma_unmap_page(tx_ring->dev,
dma_unmap_addr(tx_buf, dma),
dma_unmap_len(tx_buf, len),
DMA_TO_DEVICE);
dma_unmap_len_set(tx_buf, len, 0);
}
}
/* move us one more past the eop_desc for start of next pkt */
tx_buf++;
tx_desc++;
i++;
if (unlikely(!i)) {
i -= tx_ring->count;
tx_buf = tx_ring->tx_bi;
tx_desc = I40E_TX_DESC(tx_ring, 0);
}
prefetch(tx_desc);
/* update budget accounting */
budget--;
} while (likely(budget));
i += tx_ring->count;
tx_ring->next_to_clean = i;
u64_stats_update_begin(&tx_ring->syncp);
tx_ring->stats.bytes += total_bytes;
tx_ring->stats.packets += total_packets;
u64_stats_update_end(&tx_ring->syncp);
tx_ring->q_vector->tx.total_bytes += total_bytes;
tx_ring->q_vector->tx.total_packets += total_packets;
if (tx_ring->flags & I40E_TXR_FLAGS_WB_ON_ITR) {
/* check to see if there are < 4 descriptors
* waiting to be written back, then kick the hardware to force
* them to be written back in case we stay in NAPI.
* In this mode on X722 we do not enable Interrupt.
*/
unsigned int j = i40evf_get_tx_pending(tx_ring, false);
if (budget &&
((j / (WB_STRIDE + 1)) == 0) && (j > 0) &&
!test_bit(__I40E_DOWN, &vsi->state) &&
(I40E_DESC_UNUSED(tx_ring) != tx_ring->count))
tx_ring->arm_wb = true;
}
/* notify netdev of completed buffers */
netdev_tx_completed_queue(txring_txq(tx_ring),
total_packets, total_bytes);
#define TX_WAKE_THRESHOLD (DESC_NEEDED * 2)
if (unlikely(total_packets && netif_carrier_ok(tx_ring->netdev) &&
(I40E_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD))) {
/* Make sure that anybody stopping the queue after this
* sees the new next_to_clean.
*/
smp_mb();
if (__netif_subqueue_stopped(tx_ring->netdev,
tx_ring->queue_index) &&
!test_bit(__I40E_DOWN, &vsi->state)) {
netif_wake_subqueue(tx_ring->netdev,
tx_ring->queue_index);
++tx_ring->tx_stats.restart_queue;
}
}
return !!budget;
}
/**
* i40evf_enable_wb_on_itr - Arm hardware to do a wb, interrupts are not enabled
* @vsi: the VSI we care about
* @q_vector: the vector on which to enable writeback
*
**/
static void i40e_enable_wb_on_itr(struct i40e_vsi *vsi,
struct i40e_q_vector *q_vector)
{
u16 flags = q_vector->tx.ring[0].flags;
u32 val;
if (!(flags & I40E_TXR_FLAGS_WB_ON_ITR))
return;
if (q_vector->arm_wb_state)
return;
val = I40E_VFINT_DYN_CTLN1_WB_ON_ITR_MASK |
I40E_VFINT_DYN_CTLN1_ITR_INDX_MASK; /* set noitr */
wr32(&vsi->back->hw,
I40E_VFINT_DYN_CTLN1(q_vector->v_idx +
vsi->base_vector - 1), val);
q_vector->arm_wb_state = true;
}
/**
* i40evf_force_wb - Issue SW Interrupt so HW does a wb
* @vsi: the VSI we care about
* @q_vector: the vector on which to force writeback
*
**/
void i40evf_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector)
{
u32 val = I40E_VFINT_DYN_CTLN1_INTENA_MASK |
I40E_VFINT_DYN_CTLN1_ITR_INDX_MASK | /* set noitr */
I40E_VFINT_DYN_CTLN1_SWINT_TRIG_MASK |
I40E_VFINT_DYN_CTLN1_SW_ITR_INDX_ENA_MASK
/* allow 00 to be written to the index */;
wr32(&vsi->back->hw,
I40E_VFINT_DYN_CTLN1(q_vector->v_idx + vsi->base_vector - 1),
val);
}
/**
* i40e_set_new_dynamic_itr - Find new ITR level
* @rc: structure containing ring performance data
*
* Returns true if ITR changed, false if not
*
* Stores a new ITR value based on packets and byte counts during
* the last interrupt. The advantage of per interrupt computation
* is faster updates and more accurate ITR for the current traffic
* pattern. Constants in this function were computed based on
* theoretical maximum wire speed and thresholds were set based on
* testing data as well as attempting to minimize response time
* while increasing bulk throughput.
**/
static bool i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
{
enum i40e_latency_range new_latency_range = rc->latency_range;
struct i40e_q_vector *qv = rc->ring->q_vector;
u32 new_itr = rc->itr;
int bytes_per_int;
int usecs;
if (rc->total_packets == 0 || !rc->itr)
return false;
/* simple throttlerate management
* 0-10MB/s lowest (50000 ints/s)
* 10-20MB/s low (20000 ints/s)
* 20-1249MB/s bulk (18000 ints/s)
* > 40000 Rx packets per second (8000 ints/s)
*
* The math works out because the divisor is in 10^(-6) which
* turns the bytes/us input value into MB/s values, but
* make sure to use usecs, as the register values written
* are in 2 usec increments in the ITR registers, and make sure
* to use the smoothed values that the countdown timer gives us.
*/
usecs = (rc->itr << 1) * ITR_COUNTDOWN_START;
bytes_per_int = rc->total_bytes / usecs;
switch (new_latency_range) {
case I40E_LOWEST_LATENCY:
if (bytes_per_int > 10)
new_latency_range = I40E_LOW_LATENCY;
break;
case I40E_LOW_LATENCY:
if (bytes_per_int > 20)
new_latency_range = I40E_BULK_LATENCY;
else if (bytes_per_int <= 10)
new_latency_range = I40E_LOWEST_LATENCY;
break;
case I40E_BULK_LATENCY:
case I40E_ULTRA_LATENCY:
default:
if (bytes_per_int <= 20)
new_latency_range = I40E_LOW_LATENCY;
break;
}
/* this is to adjust RX more aggressively when streaming small
* packets. The value of 40000 was picked as it is just beyond
* what the hardware can receive per second if in low latency
* mode.
*/
#define RX_ULTRA_PACKET_RATE 40000
if ((((rc->total_packets * 1000000) / usecs) > RX_ULTRA_PACKET_RATE) &&
(&qv->rx == rc))
new_latency_range = I40E_ULTRA_LATENCY;
rc->latency_range = new_latency_range;
switch (new_latency_range) {
case I40E_LOWEST_LATENCY:
new_itr = I40E_ITR_50K;
break;
case I40E_LOW_LATENCY:
new_itr = I40E_ITR_20K;
break;
case I40E_BULK_LATENCY:
new_itr = I40E_ITR_18K;
break;
case I40E_ULTRA_LATENCY:
new_itr = I40E_ITR_8K;
break;
default:
break;
}
rc->total_bytes = 0;
rc->total_packets = 0;
if (new_itr != rc->itr) {
rc->itr = new_itr;
return true;
}
return false;
}
/**
* i40evf_setup_tx_descriptors - Allocate the Tx descriptors
* @tx_ring: the tx ring to set up
*
* Return 0 on success, negative on error
**/
int i40evf_setup_tx_descriptors(struct i40e_ring *tx_ring)
{
struct device *dev = tx_ring->dev;
int bi_size;
if (!dev)
return -ENOMEM;
/* warn if we are about to overwrite the pointer */
WARN_ON(tx_ring->tx_bi);
bi_size = sizeof(struct i40e_tx_buffer) * tx_ring->count;
tx_ring->tx_bi = kzalloc(bi_size, GFP_KERNEL);
if (!tx_ring->tx_bi)
goto err;
/* round up to nearest 4K */
tx_ring->size = tx_ring->count * sizeof(struct i40e_tx_desc);
/* add u32 for head writeback, align after this takes care of
* guaranteeing this is at least one cache line in size
*/
tx_ring->size += sizeof(u32);
tx_ring->size = ALIGN(tx_ring->size, 4096);
tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size,
&tx_ring->dma, GFP_KERNEL);
if (!tx_ring->desc) {
dev_info(dev, "Unable to allocate memory for the Tx descriptor ring, size=%d\n",
tx_ring->size);
goto err;
}
tx_ring->next_to_use = 0;
tx_ring->next_to_clean = 0;
return 0;
err:
kfree(tx_ring->tx_bi);
tx_ring->tx_bi = NULL;
return -ENOMEM;
}
/**
* i40evf_clean_rx_ring - Free Rx buffers
* @rx_ring: ring to be cleaned
**/
void i40evf_clean_rx_ring(struct i40e_ring *rx_ring)
{
struct device *dev = rx_ring->dev;
unsigned long bi_size;
u16 i;
/* ring already cleared, nothing to do */
if (!rx_ring->rx_bi)
return;
/* Free all the Rx ring sk_buffs */
for (i = 0; i < rx_ring->count; i++) {
struct i40e_rx_buffer *rx_bi = &rx_ring->rx_bi[i];
if (rx_bi->skb) {
dev_kfree_skb(rx_bi->skb);
rx_bi->skb = NULL;
}
if (!rx_bi->page)
continue;
dma_unmap_page(dev, rx_bi->dma, PAGE_SIZE, DMA_FROM_DEVICE);
__free_pages(rx_bi->page, 0);
rx_bi->page = NULL;
rx_bi->page_offset = 0;
}
bi_size = sizeof(struct i40e_rx_buffer) * rx_ring->count;
memset(rx_ring->rx_bi, 0, bi_size);
/* Zero out the descriptor ring */
memset(rx_ring->desc, 0, rx_ring->size);
rx_ring->next_to_alloc = 0;
rx_ring->next_to_clean = 0;
rx_ring->next_to_use = 0;
}
/**
* i40evf_free_rx_resources - Free Rx resources
* @rx_ring: ring to clean the resources from
*
* Free all receive software resources
**/
void i40evf_free_rx_resources(struct i40e_ring *rx_ring)
{
i40evf_clean_rx_ring(rx_ring);
kfree(rx_ring->rx_bi);
rx_ring->rx_bi = NULL;
if (rx_ring->desc) {
dma_free_coherent(rx_ring->dev, rx_ring->size,
rx_ring->desc, rx_ring->dma);
rx_ring->desc = NULL;
}
}
/**
* i40evf_setup_rx_descriptors - Allocate Rx descriptors
* @rx_ring: Rx descriptor ring (for a specific queue) to setup
*
* Returns 0 on success, negative on failure
**/
int i40evf_setup_rx_descriptors(struct i40e_ring *rx_ring)
{
struct device *dev = rx_ring->dev;
int bi_size;
/* warn if we are about to overwrite the pointer */
WARN_ON(rx_ring->rx_bi);
bi_size = sizeof(struct i40e_rx_buffer) * rx_ring->count;
rx_ring->rx_bi = kzalloc(bi_size, GFP_KERNEL);
if (!rx_ring->rx_bi)
goto err;
u64_stats_init(&rx_ring->syncp);
/* Round up to nearest 4K */
rx_ring->size = rx_ring->count * sizeof(union i40e_32byte_rx_desc);
rx_ring->size = ALIGN(rx_ring->size, 4096);
rx_ring->desc = dma_alloc_coherent(dev, rx_ring->size,
&rx_ring->dma, GFP_KERNEL);
if (!rx_ring->desc) {
dev_info(dev, "Unable to allocate memory for the Rx descriptor ring, size=%d\n",
rx_ring->size);
goto err;
}
rx_ring->next_to_alloc = 0;
rx_ring->next_to_clean = 0;
rx_ring->next_to_use = 0;
return 0;
err:
kfree(rx_ring->rx_bi);
rx_ring->rx_bi = NULL;
return -ENOMEM;
}
/**
* i40e_release_rx_desc - Store the new tail and head values
* @rx_ring: ring to bump
* @val: new head index
**/
static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val)
{
rx_ring->next_to_use = val;
/* update next to alloc since we have filled the ring */
rx_ring->next_to_alloc = val;
/* Force memory writes to complete before letting h/w
* know there are new descriptors to fetch. (Only
* applicable for weak-ordered memory model archs,
* such as IA-64).
*/
wmb();
writel(val, rx_ring->tail);
}
/**
* i40e_alloc_mapped_page - recycle or make a new page
* @rx_ring: ring to use
* @bi: rx_buffer struct to modify
*
* Returns true if the page was successfully allocated or
* reused.
**/
static bool i40e_alloc_mapped_page(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *bi)
{
struct page *page = bi->page;
dma_addr_t dma;
/* since we are recycling buffers we should seldom need to alloc */
if (likely(page)) {
rx_ring->rx_stats.page_reuse_count++;
return true;
}
/* alloc new page for storage */
page = dev_alloc_page();
if (unlikely(!page)) {
rx_ring->rx_stats.alloc_page_failed++;
return false;
}
/* map page for use */
dma = dma_map_page(rx_ring->dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE);
/* if mapping failed free memory back to system since
* there isn't much point in holding memory we can't use
*/
if (dma_mapping_error(rx_ring->dev, dma)) {
__free_pages(page, 0);
rx_ring->rx_stats.alloc_page_failed++;
return false;
}
bi->dma = dma;
bi->page = page;
bi->page_offset = 0;
return true;
}
/**
* i40e_receive_skb - Send a completed packet up the stack
* @rx_ring: rx ring in play
* @skb: packet to send up
* @vlan_tag: vlan tag for packet
**/
static void i40e_receive_skb(struct i40e_ring *rx_ring,
struct sk_buff *skb, u16 vlan_tag)
{
struct i40e_q_vector *q_vector = rx_ring->q_vector;
if ((rx_ring->netdev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
(vlan_tag & VLAN_VID_MASK))
__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tag);
napi_gro_receive(&q_vector->napi, skb);
}
/**
* i40evf_alloc_rx_buffers - Replace used receive buffers
* @rx_ring: ring to place buffers on
* @cleaned_count: number of buffers to replace
*
* Returns false if all allocations were successful, true if any fail
**/
bool i40evf_alloc_rx_buffers(struct i40e_ring *rx_ring, u16 cleaned_count)
{
u16 ntu = rx_ring->next_to_use;
union i40e_rx_desc *rx_desc;
struct i40e_rx_buffer *bi;
/* do nothing if no valid netdev defined */
if (!rx_ring->netdev || !cleaned_count)
return false;
rx_desc = I40E_RX_DESC(rx_ring, ntu);
bi = &rx_ring->rx_bi[ntu];
do {
if (!i40e_alloc_mapped_page(rx_ring, bi))
goto no_buffers;
/* Refresh the desc even if buffer_addrs didn't change
* because each write-back erases this info.
*/
rx_desc->read.pkt_addr = cpu_to_le64(bi->dma + bi->page_offset);
rx_desc->read.hdr_addr = 0;
rx_desc++;
bi++;
ntu++;
if (unlikely(ntu == rx_ring->count)) {
rx_desc = I40E_RX_DESC(rx_ring, 0);
bi = rx_ring->rx_bi;
ntu = 0;
}
/* clear the status bits for the next_to_use descriptor */
rx_desc->wb.qword1.status_error_len = 0;
cleaned_count--;
} while (cleaned_count);
if (rx_ring->next_to_use != ntu)
i40e_release_rx_desc(rx_ring, ntu);
return false;
no_buffers:
if (rx_ring->next_to_use != ntu)
i40e_release_rx_desc(rx_ring, ntu);
/* make sure to come back via polling to try again after
* allocation failure
*/
return true;
}
/**
* i40e_rx_checksum - Indicate in skb if hw indicated a good cksum
* @vsi: the VSI we care about
* @skb: skb currently being received and modified
* @rx_desc: the receive descriptor
*
* skb->protocol must be set before this function is called
**/
static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
struct sk_buff *skb,
union i40e_rx_desc *rx_desc)
{
struct i40e_rx_ptype_decoded decoded;
u32 rx_error, rx_status;
bool ipv4, ipv6;
u8 ptype;
u64 qword;
qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
ptype = (qword & I40E_RXD_QW1_PTYPE_MASK) >> I40E_RXD_QW1_PTYPE_SHIFT;
rx_error = (qword & I40E_RXD_QW1_ERROR_MASK) >>
I40E_RXD_QW1_ERROR_SHIFT;
rx_status = (qword & I40E_RXD_QW1_STATUS_MASK) >>
I40E_RXD_QW1_STATUS_SHIFT;
decoded = decode_rx_desc_ptype(ptype);
skb->ip_summed = CHECKSUM_NONE;
skb_checksum_none_assert(skb);
/* Rx csum enabled and ip headers found? */
if (!(vsi->netdev->features & NETIF_F_RXCSUM))
return;
/* did the hardware decode the packet and checksum? */
if (!(rx_status & BIT(I40E_RX_DESC_STATUS_L3L4P_SHIFT)))
return;
/* both known and outer_ip must be set for the below code to work */
if (!(decoded.known && decoded.outer_ip))
return;
ipv4 = (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP) &&
(decoded.outer_ip_ver == I40E_RX_PTYPE_OUTER_IPV4);
ipv6 = (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP) &&
(decoded.outer_ip_ver == I40E_RX_PTYPE_OUTER_IPV6);
if (ipv4 &&
(rx_error & (BIT(I40E_RX_DESC_ERROR_IPE_SHIFT) |
BIT(I40E_RX_DESC_ERROR_EIPE_SHIFT))))
goto checksum_fail;
/* likely incorrect csum if alternate IP extension headers found */
if (ipv6 &&
rx_status & BIT(I40E_RX_DESC_STATUS_IPV6EXADD_SHIFT))
/* don't increment checksum err here, non-fatal err */
return;
/* there was some L4 error, count error and punt packet to the stack */
if (rx_error & BIT(I40E_RX_DESC_ERROR_L4E_SHIFT))
goto checksum_fail;
/* handle packets that were not able to be checksummed due
* to arrival speed, in this case the stack can compute
* the csum.
*/
if (rx_error & BIT(I40E_RX_DESC_ERROR_PPRS_SHIFT))
return;
/* If there is an outer header present that might contain a checksum
* we need to bump the checksum level by 1 to reflect the fact that
* we are indicating we validated the inner checksum.
*/
if (decoded.tunnel_type >= I40E_RX_PTYPE_TUNNEL_IP_GRENAT)
skb->csum_level = 1;
/* Only report checksum unnecessary for TCP, UDP, or SCTP */
switch (decoded.inner_prot) {
case I40E_RX_PTYPE_INNER_PROT_TCP:
case I40E_RX_PTYPE_INNER_PROT_UDP:
case I40E_RX_PTYPE_INNER_PROT_SCTP:
skb->ip_summed = CHECKSUM_UNNECESSARY;
/* fall though */
default:
break;
}
return;
checksum_fail:
vsi->back->hw_csum_rx_error++;
}
/**
* i40e_ptype_to_htype - get a hash type
* @ptype: the ptype value from the descriptor
*
* Returns a hash type to be used by skb_set_hash
**/
static inline int i40e_ptype_to_htype(u8 ptype)
{
struct i40e_rx_ptype_decoded decoded = decode_rx_desc_ptype(ptype);
if (!decoded.known)
return PKT_HASH_TYPE_NONE;
if (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP &&
decoded.payload_layer == I40E_RX_PTYPE_PAYLOAD_LAYER_PAY4)
return PKT_HASH_TYPE_L4;
else if (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP &&
decoded.payload_layer == I40E_RX_PTYPE_PAYLOAD_LAYER_PAY3)
return PKT_HASH_TYPE_L3;
else
return PKT_HASH_TYPE_L2;
}
/**
* i40e_rx_hash - set the hash value in the skb
* @ring: descriptor ring
* @rx_desc: specific descriptor
**/
static inline void i40e_rx_hash(struct i40e_ring *ring,
union i40e_rx_desc *rx_desc,
struct sk_buff *skb,
u8 rx_ptype)
{
u32 hash;
const __le64 rss_mask =
cpu_to_le64((u64)I40E_RX_DESC_FLTSTAT_RSS_HASH <<
I40E_RX_DESC_STATUS_FLTSTAT_SHIFT);
if (ring->netdev->features & NETIF_F_RXHASH)
return;
if ((rx_desc->wb.qword1.status_error_len & rss_mask) == rss_mask) {
hash = le32_to_cpu(rx_desc->wb.qword0.hi_dword.rss);
skb_set_hash(skb, hash, i40e_ptype_to_htype(rx_ptype));
}
}
/**
* i40evf_process_skb_fields - Populate skb header fields from Rx descriptor
* @rx_ring: rx descriptor ring packet is being transacted on
* @rx_desc: pointer to the EOP Rx descriptor
* @skb: pointer to current skb being populated
* @rx_ptype: the packet type decoded by hardware
*
* This function checks the ring, descriptor, and packet information in
* order to populate the hash, checksum, VLAN, protocol, and
* other fields within the skb.
**/
static inline
void i40evf_process_skb_fields(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc, struct sk_buff *skb,
u8 rx_ptype)
{
i40e_rx_hash(rx_ring, rx_desc, skb, rx_ptype);
/* modifies the skb - consumes the enet header */
skb->protocol = eth_type_trans(skb, rx_ring->netdev);
i40e_rx_checksum(rx_ring->vsi, skb, rx_desc);
skb_record_rx_queue(skb, rx_ring->queue_index);
}
/**
* i40e_pull_tail - i40e specific version of skb_pull_tail
* @rx_ring: rx descriptor ring packet is being transacted on
* @skb: pointer to current skb being adjusted
*
* This function is an i40e specific version of __pskb_pull_tail. The
* main difference between this version and the original function is that
* this function can make several assumptions about the state of things
* that allow for significant optimizations versus the standard function.
* As a result we can do things like drop a frag and maintain an accurate
* truesize for the skb.
*/
static void i40e_pull_tail(struct i40e_ring *rx_ring, struct sk_buff *skb)
{
struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];
unsigned char *va;
unsigned int pull_len;
/* it is valid to use page_address instead of kmap since we are
* working with pages allocated out of the lomem pool per
* alloc_page(GFP_ATOMIC)
*/
va = skb_frag_address(frag);
/* we need the header to contain the greater of either ETH_HLEN or
* 60 bytes if the skb->len is less than 60 for skb_pad.
*/
pull_len = eth_get_headlen(va, I40E_RX_HDR_SIZE);
/* align pull length to size of long to optimize memcpy performance */
skb_copy_to_linear_data(skb, va, ALIGN(pull_len, sizeof(long)));
/* update all of the pointers */
skb_frag_size_sub(frag, pull_len);
frag->page_offset += pull_len;
skb->data_len -= pull_len;
skb->tail += pull_len;
}
/**
* i40e_cleanup_headers - Correct empty headers
* @rx_ring: rx descriptor ring packet is being transacted on
* @skb: pointer to current skb being fixed
*
* Also address the case where we are pulling data in on pages only
* and as such no data is present in the skb header.
*
* In addition if skb is not at least 60 bytes we need to pad it so that
* it is large enough to qualify as a valid Ethernet frame.
*
* Returns true if an error was encountered and skb was freed.
**/
static bool i40e_cleanup_headers(struct i40e_ring *rx_ring, struct sk_buff *skb)
{
/* place header in linear portion of buffer */
if (skb_is_nonlinear(skb))
i40e_pull_tail(rx_ring, skb);
/* if eth_skb_pad returns an error the skb was freed */
if (eth_skb_pad(skb))
return true;
return false;
}
/**
* i40e_reuse_rx_page - page flip buffer and store it back on the ring
* @rx_ring: rx descriptor ring to store buffers on
* @old_buff: donor buffer to have page reused
*
* Synchronizes page for reuse by the adapter
**/
static void i40e_reuse_rx_page(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *old_buff)
{
struct i40e_rx_buffer *new_buff;
u16 nta = rx_ring->next_to_alloc;
new_buff = &rx_ring->rx_bi[nta];
/* update, and store next to alloc */
nta++;
rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0;
/* transfer page from old buffer to new buffer */
*new_buff = *old_buff;
}
/**
* i40e_page_is_reserved - check if reuse is possible
* @page: page struct to check
*/
static inline bool i40e_page_is_reserved(struct page *page)
{
return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
}
/**
* i40e_add_rx_frag - Add contents of Rx buffer to sk_buff
* @rx_ring: rx descriptor ring to transact packets on
* @rx_buffer: buffer containing page to add
* @rx_desc: descriptor containing length of buffer written by hardware
* @skb: sk_buff to place the data into
*
* This function will add the data contained in rx_buffer->page to the skb.
* This is done either through a direct copy if the data in the buffer is
* less than the skb header size, otherwise it will just attach the page as
* a frag to the skb.
*
* The function will then update the page offset if necessary and return
* true if the buffer can be reused by the adapter.
**/
static bool i40e_add_rx_frag(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer,
union i40e_rx_desc *rx_desc,
struct sk_buff *skb)
{
struct page *page = rx_buffer->page;
u64 qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
unsigned int size = (qword & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
I40E_RXD_QW1_LENGTH_PBUF_SHIFT;
#if (PAGE_SIZE < 8192)
unsigned int truesize = I40E_RXBUFFER_2048;
#else
unsigned int truesize = ALIGN(size, L1_CACHE_BYTES);
unsigned int last_offset = PAGE_SIZE - I40E_RXBUFFER_2048;
#endif
/* will the data fit in the skb we allocated? if so, just
* copy it as it is pretty small anyway
*/
if ((size <= I40E_RX_HDR_SIZE) && !skb_is_nonlinear(skb)) {
unsigned char *va = page_address(page) + rx_buffer->page_offset;
memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long)));
/* page is not reserved, we can reuse buffer as-is */
if (likely(!i40e_page_is_reserved(page)))
return true;
/* this page cannot be reused so discard it */
__free_pages(page, 0);
return false;
}
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
rx_buffer->page_offset, size, truesize);
/* avoid re-using remote pages */
if (unlikely(i40e_page_is_reserved(page)))
return false;
#if (PAGE_SIZE < 8192)
/* if we are only owner of page we can reuse it */
if (unlikely(page_count(page) != 1))
return false;
/* flip page offset to other buffer */
rx_buffer->page_offset ^= truesize;
#else
/* move offset up to the next cache line */
rx_buffer->page_offset += truesize;
if (rx_buffer->page_offset > last_offset)
return false;
#endif
/* Even if we own the page, we are not allowed to use atomic_set()
* This would break get_page_unless_zero() users.
*/
get_page(rx_buffer->page);
return true;
}
/**
* i40evf_fetch_rx_buffer - Allocate skb and populate it
* @rx_ring: rx descriptor ring to transact packets on
* @rx_desc: descriptor containing info written by hardware
*
* This function allocates an skb on the fly, and populates it with the page
* data from the current receive descriptor, taking care to set up the skb
* correctly, as well as handling calling the page recycle function if
* necessary.
*/
static inline
struct sk_buff *i40evf_fetch_rx_buffer(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc)
{
struct i40e_rx_buffer *rx_buffer;
struct sk_buff *skb;
struct page *page;
rx_buffer = &rx_ring->rx_bi[rx_ring->next_to_clean];
page = rx_buffer->page;
prefetchw(page);
skb = rx_buffer->skb;
if (likely(!skb)) {
void *page_addr = page_address(page) + rx_buffer->page_offset;
/* prefetch first cache line of first page */
prefetch(page_addr);
#if L1_CACHE_BYTES < 128
prefetch(page_addr + L1_CACHE_BYTES);
#endif
/* allocate a skb to store the frags */
skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
I40E_RX_HDR_SIZE,
GFP_ATOMIC | __GFP_NOWARN);
if (unlikely(!skb)) {
rx_ring->rx_stats.alloc_buff_failed++;
return NULL;
}
/* we will be copying header into skb->data in
* pskb_may_pull so it is in our interest to prefetch
* it now to avoid a possible cache miss
*/
prefetchw(skb->data);
} else {
rx_buffer->skb = NULL;
}
/* we are reusing so sync this buffer for CPU use */
dma_sync_single_range_for_cpu(rx_ring->dev,
rx_buffer->dma,
rx_buffer->page_offset,
I40E_RXBUFFER_2048,
DMA_FROM_DEVICE);
/* pull page into skb */
if (i40e_add_rx_frag(rx_ring, rx_buffer, rx_desc, skb)) {
/* hand second half of page back to the ring */
i40e_reuse_rx_page(rx_ring, rx_buffer);
rx_ring->rx_stats.page_reuse_count++;
} else {
/* we are not reusing the buffer so unmap it */
dma_unmap_page(rx_ring->dev, rx_buffer->dma, PAGE_SIZE,
DMA_FROM_DEVICE);
}
/* clear contents of buffer_info */
rx_buffer->page = NULL;
return skb;
}
/**
* i40e_is_non_eop - process handling of non-EOP buffers
* @rx_ring: Rx ring being processed
* @rx_desc: Rx descriptor for current buffer
* @skb: Current socket buffer containing buffer in progress
*
* This function updates next to clean. If the buffer is an EOP buffer
* this function exits returning false, otherwise it will place the
* sk_buff in the next buffer to be chained and return true indicating
* that this is in fact a non-EOP buffer.
**/
static bool i40e_is_non_eop(struct i40e_ring *rx_ring,
union i40e_rx_desc *rx_desc,
struct sk_buff *skb)
{
u32 ntc = rx_ring->next_to_clean + 1;
/* fetch, update, and store next to clean */
ntc = (ntc < rx_ring->count) ? ntc : 0;
rx_ring->next_to_clean = ntc;
prefetch(I40E_RX_DESC(rx_ring, ntc));
/* if we are the last buffer then there is nothing else to do */
#define I40E_RXD_EOF BIT(I40E_RX_DESC_STATUS_EOF_SHIFT)
if (likely(i40e_test_staterr(rx_desc, I40E_RXD_EOF)))
return false;
/* place skb in next buffer to be received */
rx_ring->rx_bi[ntc].skb = skb;
rx_ring->rx_stats.non_eop_descs++;
return true;
}
/**
* i40e_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
* @rx_ring: rx descriptor ring to transact packets on
* @budget: Total limit on number of packets to process
*
* This function provides a "bounce buffer" approach to Rx interrupt
* processing. The advantage to this is that on systems that have
* expensive overhead for IOMMU access this provides a means of avoiding
* it by maintaining the mapping of the page to the system.
*
* Returns amount of work completed
**/
static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
{
unsigned int total_rx_bytes = 0, total_rx_packets = 0;
u16 cleaned_count = I40E_DESC_UNUSED(rx_ring);
bool failure = false;
while (likely(total_rx_packets < budget)) {
union i40e_rx_desc *rx_desc;
struct sk_buff *skb;
u32 rx_status;
u16 vlan_tag;
u8 rx_ptype;
u64 qword;
/* return some buffers to hardware, one at a time is too slow */
if (cleaned_count >= I40E_RX_BUFFER_WRITE) {
failure = failure ||
i40evf_alloc_rx_buffers(rx_ring, cleaned_count);
cleaned_count = 0;
}
rx_desc = I40E_RX_DESC(rx_ring, rx_ring->next_to_clean);
qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
rx_ptype = (qword & I40E_RXD_QW1_PTYPE_MASK) >>
I40E_RXD_QW1_PTYPE_SHIFT;
rx_status = (qword & I40E_RXD_QW1_STATUS_MASK) >>
I40E_RXD_QW1_STATUS_SHIFT;
if (!(rx_status & BIT(I40E_RX_DESC_STATUS_DD_SHIFT)))
break;
/* status_error_len will always be zero for unused descriptors
* because it's cleared in cleanup, and overlaps with hdr_addr
* which is always zero because packet split isn't used, if the
* hardware wrote DD then it will be non-zero
*/
if (!rx_desc->wb.qword1.status_error_len)
break;
/* This memory barrier is needed to keep us from reading
* any other fields out of the rx_desc until we know the
* DD bit is set.
*/
dma_rmb();
skb = i40evf_fetch_rx_buffer(rx_ring, rx_desc);
if (!skb)
break;
cleaned_count++;
if (i40e_is_non_eop(rx_ring, rx_desc, skb))
continue;
/* ERR_MASK will only have valid bits if EOP set, and
* what we are doing here is actually checking
* I40E_RX_DESC_ERROR_RXE_SHIFT, since it is the zeroth bit in
* the error field
*/
if (unlikely(i40e_test_staterr(rx_desc, BIT(I40E_RXD_QW1_ERROR_SHIFT)))) {
dev_kfree_skb_any(skb);
continue;
}
if (i40e_cleanup_headers(rx_ring, skb))
continue;
/* probably a little skewed due to removing CRC */
total_rx_bytes += skb->len;
/* populate checksum, VLAN, and protocol */
i40evf_process_skb_fields(rx_ring, rx_desc, skb, rx_ptype);
vlan_tag = (qword & BIT(I40E_RX_DESC_STATUS_L2TAG1P_SHIFT)) ?
le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1) : 0;
i40e_receive_skb(rx_ring, skb, vlan_tag);
/* update budget accounting */
total_rx_packets++;
}
u64_stats_update_begin(&rx_ring->syncp);
rx_ring->stats.packets += total_rx_packets;
rx_ring->stats.bytes += total_rx_bytes;
u64_stats_update_end(&rx_ring->syncp);
rx_ring->q_vector->rx.total_packets += total_rx_packets;
rx_ring->q_vector->rx.total_bytes += total_rx_bytes;
/* guarantee a trip back through this routine if there was a failure */
return failure ? budget : total_rx_packets;
}
static u32 i40e_buildreg_itr(const int type, const u16 itr)
{
u32 val;
val = I40E_VFINT_DYN_CTLN1_INTENA_MASK |
/* Don't clear PBA because that can cause lost interrupts that
* came in while we were cleaning/polling
*/
(type << I40E_VFINT_DYN_CTLN1_ITR_INDX_SHIFT) |
(itr << I40E_VFINT_DYN_CTLN1_INTERVAL_SHIFT);
return val;
}
/* a small macro to shorten up some long lines */
#define INTREG I40E_VFINT_DYN_CTLN1
static inline int get_rx_itr_enabled(struct i40e_vsi *vsi, int idx)
{
struct i40evf_adapter *adapter = vsi->back;
return !!(adapter->rx_rings[idx].rx_itr_setting);
}
static inline int get_tx_itr_enabled(struct i40e_vsi *vsi, int idx)
{
struct i40evf_adapter *adapter = vsi->back;
return !!(adapter->tx_rings[idx].tx_itr_setting);
}
/**
* i40e_update_enable_itr - Update itr and re-enable MSIX interrupt
* @vsi: the VSI we care about
* @q_vector: q_vector for which itr is being updated and interrupt enabled
*
**/
static inline void i40e_update_enable_itr(struct i40e_vsi *vsi,
struct i40e_q_vector *q_vector)
{
struct i40e_hw *hw = &vsi->back->hw;
bool rx = false, tx = false;
u32 rxval, txval;
int vector;
int idx = q_vector->v_idx;
int rx_itr_setting, tx_itr_setting;
vector = (q_vector->v_idx + vsi->base_vector);
/* avoid dynamic calculation if in countdown mode OR if
* all dynamic is disabled
*/
rxval = txval = i40e_buildreg_itr(I40E_ITR_NONE, 0);
rx_itr_setting = get_rx_itr_enabled(vsi, idx);
tx_itr_setting = get_tx_itr_enabled(vsi, idx);
if (q_vector->itr_countdown > 0 ||
(!ITR_IS_DYNAMIC(rx_itr_setting) &&
!ITR_IS_DYNAMIC(tx_itr_setting))) {
goto enable_int;
}
if (ITR_IS_DYNAMIC(rx_itr_setting)) {
rx = i40e_set_new_dynamic_itr(&q_vector->rx);
rxval = i40e_buildreg_itr(I40E_RX_ITR, q_vector->rx.itr);
}
if (ITR_IS_DYNAMIC(tx_itr_setting)) {
tx = i40e_set_new_dynamic_itr(&q_vector->tx);
txval = i40e_buildreg_itr(I40E_TX_ITR, q_vector->tx.itr);
}
if (rx || tx) {
/* get the higher of the two ITR adjustments and
* use the same value for both ITR registers
* when in adaptive mode (Rx and/or Tx)
*/
u16 itr = max(q_vector->tx.itr, q_vector->rx.itr);
q_vector->tx.itr = q_vector->rx.itr = itr;
txval = i40e_buildreg_itr(I40E_TX_ITR, itr);
tx = true;
rxval = i40e_buildreg_itr(I40E_RX_ITR, itr);
rx = true;
}
/* only need to enable the interrupt once, but need
* to possibly update both ITR values
*/
if (rx) {
/* set the INTENA_MSK_MASK so that this first write
* won't actually enable the interrupt, instead just
* updating the ITR (it's bit 31 PF and VF)
*/
rxval |= BIT(31);
/* don't check _DOWN because interrupt isn't being enabled */
wr32(hw, INTREG(vector - 1), rxval);
}
enable_int:
if (!test_bit(__I40E_DOWN, &vsi->state))
wr32(hw, INTREG(vector - 1), txval);
if (q_vector->itr_countdown)
q_vector->itr_countdown--;
else
q_vector->itr_countdown = ITR_COUNTDOWN_START;
}
/**
* i40evf_napi_poll - NAPI polling Rx/Tx cleanup routine
* @napi: napi struct with our devices info in it
* @budget: amount of work driver is allowed to do this pass, in packets
*
* This function will clean all queues associated with a q_vector.
*
* Returns the amount of work done
**/
int i40evf_napi_poll(struct napi_struct *napi, int budget)
{
struct i40e_q_vector *q_vector =
container_of(napi, struct i40e_q_vector, napi);
struct i40e_vsi *vsi = q_vector->vsi;
struct i40e_ring *ring;
bool clean_complete = true;
bool arm_wb = false;
int budget_per_ring;
int work_done = 0;
if (test_bit(__I40E_DOWN, &vsi->state)) {
napi_complete(napi);
return 0;
}
/* Since the actual Tx work is minimal, we can give the Tx a larger
* budget and be more aggressive about cleaning up the Tx descriptors.
*/
i40e_for_each_ring(ring, q_vector->tx) {
if (!i40e_clean_tx_irq(vsi, ring, budget)) {
clean_complete = false;
continue;
}
arm_wb |= ring->arm_wb;
ring->arm_wb = false;
}
/* Handle case where we are called by netpoll with a budget of 0 */
if (budget <= 0)
goto tx_only;
/* We attempt to distribute budget to each Rx queue fairly, but don't
* allow the budget to go below 1 because that would exit polling early.
*/
budget_per_ring = max(budget/q_vector->num_ringpairs, 1);
i40e_for_each_ring(ring, q_vector->rx) {
int cleaned = i40e_clean_rx_irq(ring, budget_per_ring);
work_done += cleaned;
/* if we clean as many as budgeted, we must not be done */
if (cleaned >= budget_per_ring)
clean_complete = false;
}
/* If work not completed, return budget and polling will return */
if (!clean_complete) {
tx_only:
if (arm_wb) {
q_vector->tx.ring[0].tx_stats.tx_force_wb++;
i40e_enable_wb_on_itr(vsi, q_vector);
}
return budget;
}
if (vsi->back->flags & I40E_TXR_FLAGS_WB_ON_ITR)
q_vector->arm_wb_state = false;
/* Work is done so exit the polling mode and re-enable the interrupt */
napi_complete_done(napi, work_done);
i40e_update_enable_itr(vsi, q_vector);
return 0;
}
/**
* i40evf_tx_prepare_vlan_flags - prepare generic TX VLAN tagging flags for HW
* @skb: send buffer
* @tx_ring: ring to send buffer on
* @flags: the tx flags to be set
*
* Checks the skb and set up correspondingly several generic transmit flags
* related to VLAN tagging for the HW, such as VLAN, DCB, etc.
*
* Returns error code indicate the frame should be dropped upon error and the
* otherwise returns 0 to indicate the flags has been set properly.
**/
static inline int i40evf_tx_prepare_vlan_flags(struct sk_buff *skb,
struct i40e_ring *tx_ring,
u32 *flags)
{
__be16 protocol = skb->protocol;
u32 tx_flags = 0;
if (protocol == htons(ETH_P_8021Q) &&
!(tx_ring->netdev->features & NETIF_F_HW_VLAN_CTAG_TX)) {
/* When HW VLAN acceleration is turned off by the user the
* stack sets the protocol to 8021q so that the driver
* can take any steps required to support the SW only
* VLAN handling. In our case the driver doesn't need
* to take any further steps so just set the protocol
* to the encapsulated ethertype.
*/
skb->protocol = vlan_get_protocol(skb);
goto out;
}
/* if we have a HW VLAN tag being added, default to the HW one */
if (skb_vlan_tag_present(skb)) {
tx_flags |= skb_vlan_tag_get(skb) << I40E_TX_FLAGS_VLAN_SHIFT;
tx_flags |= I40E_TX_FLAGS_HW_VLAN;
/* else if it is a SW VLAN, check the next protocol and store the tag */
} else if (protocol == htons(ETH_P_8021Q)) {
struct vlan_hdr *vhdr, _vhdr;
vhdr = skb_header_pointer(skb, ETH_HLEN, sizeof(_vhdr), &_vhdr);
if (!vhdr)
return -EINVAL;
protocol = vhdr->h_vlan_encapsulated_proto;
tx_flags |= ntohs(vhdr->h_vlan_TCI) << I40E_TX_FLAGS_VLAN_SHIFT;
tx_flags |= I40E_TX_FLAGS_SW_VLAN;
}
out:
*flags = tx_flags;
return 0;
}
/**
* i40e_tso - set up the tso context descriptor
* @skb: ptr to the skb we're sending
* @hdr_len: ptr to the size of the packet header
* @cd_type_cmd_tso_mss: Quad Word 1
*
* Returns 0 if no TSO can happen, 1 if tso is going, or error
**/
static int i40e_tso(struct sk_buff *skb, u8 *hdr_len, u64 *cd_type_cmd_tso_mss)
{
u64 cd_cmd, cd_tso_len, cd_mss;
union {
struct iphdr *v4;
struct ipv6hdr *v6;
unsigned char *hdr;
} ip;
union {
struct tcphdr *tcp;
struct udphdr *udp;
unsigned char *hdr;
} l4;
u32 paylen, l4_offset;
int err;
if (skb->ip_summed != CHECKSUM_PARTIAL)
return 0;
if (!skb_is_gso(skb))
return 0;
err = skb_cow_head(skb, 0);
if (err < 0)
return err;
ip.hdr = skb_network_header(skb);
l4.hdr = skb_transport_header(skb);
/* initialize outer IP header fields */
if (ip.v4->version == 4) {
ip.v4->tot_len = 0;
ip.v4->check = 0;
} else {
ip.v6->payload_len = 0;
}
if (skb_shinfo(skb)->gso_type & (SKB_GSO_GRE |
SKB_GSO_GRE_CSUM |
SKB_GSO_IPXIP4 |
SKB_GSO_IPXIP6 |
SKB_GSO_UDP_TUNNEL |
SKB_GSO_UDP_TUNNEL_CSUM)) {
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) &&
(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)) {
l4.udp->len = 0;
/* determine offset of outer transport header */
l4_offset = l4.hdr - skb->data;
/* remove payload length from outer checksum */
paylen = skb->len - l4_offset;
csum_replace_by_diff(&l4.udp->check, htonl(paylen));
}
/* reset pointers to inner headers */
ip.hdr = skb_inner_network_header(skb);
l4.hdr = skb_inner_transport_header(skb);
/* initialize inner IP header fields */
if (ip.v4->version == 4) {
ip.v4->tot_len = 0;
ip.v4->check = 0;
} else {
ip.v6->payload_len = 0;
}
}
/* determine offset of inner transport header */
l4_offset = l4.hdr - skb->data;
/* remove payload length from inner checksum */
paylen = skb->len - l4_offset;
csum_replace_by_diff(&l4.tcp->check, htonl(paylen));
/* compute length of segmentation header */
*hdr_len = (l4.tcp->doff * 4) + l4_offset;
/* find the field values */
cd_cmd = I40E_TX_CTX_DESC_TSO;
cd_tso_len = skb->len - *hdr_len;
cd_mss = skb_shinfo(skb)->gso_size;
*cd_type_cmd_tso_mss |= (cd_cmd << I40E_TXD_CTX_QW1_CMD_SHIFT) |
(cd_tso_len << I40E_TXD_CTX_QW1_TSO_LEN_SHIFT) |
(cd_mss << I40E_TXD_CTX_QW1_MSS_SHIFT);
return 1;
}
/**
* i40e_tx_enable_csum - Enable Tx checksum offloads
* @skb: send buffer
* @tx_flags: pointer to Tx flags currently set
* @td_cmd: Tx descriptor command bits to set
* @td_offset: Tx descriptor header offsets to set
* @tx_ring: Tx descriptor ring
* @cd_tunneling: ptr to context desc bits
**/
static int i40e_tx_enable_csum(struct sk_buff *skb, u32 *tx_flags,
u32 *td_cmd, u32 *td_offset,
struct i40e_ring *tx_ring,
u32 *cd_tunneling)
{
union {
struct iphdr *v4;
struct ipv6hdr *v6;
unsigned char *hdr;
} ip;
union {
struct tcphdr *tcp;
struct udphdr *udp;
unsigned char *hdr;
} l4;
unsigned char *exthdr;
u32 offset, cmd = 0;
__be16 frag_off;
u8 l4_proto = 0;
if (skb->ip_summed != CHECKSUM_PARTIAL)
return 0;
ip.hdr = skb_network_header(skb);
l4.hdr = skb_transport_header(skb);
/* compute outer L2 header size */
offset = ((ip.hdr - skb->data) / 2) << I40E_TX_DESC_LENGTH_MACLEN_SHIFT;
if (skb->encapsulation) {
u32 tunnel = 0;
/* define outer network header type */
if (*tx_flags & I40E_TX_FLAGS_IPV4) {
tunnel |= (*tx_flags & I40E_TX_FLAGS_TSO) ?
I40E_TX_CTX_EXT_IP_IPV4 :
I40E_TX_CTX_EXT_IP_IPV4_NO_CSUM;
l4_proto = ip.v4->protocol;
} else if (*tx_flags & I40E_TX_FLAGS_IPV6) {
tunnel |= I40E_TX_CTX_EXT_IP_IPV6;
exthdr = ip.hdr + sizeof(*ip.v6);
l4_proto = ip.v6->nexthdr;
if (l4.hdr != exthdr)
ipv6_skip_exthdr(skb, exthdr - skb->data,
&l4_proto, &frag_off);
}
/* define outer transport */
switch (l4_proto) {
case IPPROTO_UDP:
tunnel |= I40E_TXD_CTX_UDP_TUNNELING;
*tx_flags |= I40E_TX_FLAGS_VXLAN_TUNNEL;
break;
case IPPROTO_GRE:
tunnel |= I40E_TXD_CTX_GRE_TUNNELING;
*tx_flags |= I40E_TX_FLAGS_VXLAN_TUNNEL;
break;
case IPPROTO_IPIP:
case IPPROTO_IPV6:
*tx_flags |= I40E_TX_FLAGS_VXLAN_TUNNEL;
l4.hdr = skb_inner_network_header(skb);
break;
default:
if (*tx_flags & I40E_TX_FLAGS_TSO)
return -1;
skb_checksum_help(skb);
return 0;
}
/* compute outer L3 header size */
tunnel |= ((l4.hdr - ip.hdr) / 4) <<
I40E_TXD_CTX_QW0_EXT_IPLEN_SHIFT;
/* switch IP header pointer from outer to inner header */
ip.hdr = skb_inner_network_header(skb);
/* compute tunnel header size */
tunnel |= ((ip.hdr - l4.hdr) / 2) <<
I40E_TXD_CTX_QW0_NATLEN_SHIFT;
/* indicate if we need to offload outer UDP header */
if ((*tx_flags & I40E_TX_FLAGS_TSO) &&
!(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) &&
(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM))
tunnel |= I40E_TXD_CTX_QW0_L4T_CS_MASK;
/* record tunnel offload values */
*cd_tunneling |= tunnel;
/* switch L4 header pointer from outer to inner */
l4.hdr = skb_inner_transport_header(skb);
l4_proto = 0;
/* reset type as we transition from outer to inner headers */
*tx_flags &= ~(I40E_TX_FLAGS_IPV4 | I40E_TX_FLAGS_IPV6);
if (ip.v4->version == 4)
*tx_flags |= I40E_TX_FLAGS_IPV4;
if (ip.v6->version == 6)
*tx_flags |= I40E_TX_FLAGS_IPV6;
}
/* Enable IP checksum offloads */
if (*tx_flags & I40E_TX_FLAGS_IPV4) {
l4_proto = ip.v4->protocol;
/* the stack computes the IP header already, the only time we
* need the hardware to recompute it is in the case of TSO.
*/
cmd |= (*tx_flags & I40E_TX_FLAGS_TSO) ?
I40E_TX_DESC_CMD_IIPT_IPV4_CSUM :
I40E_TX_DESC_CMD_IIPT_IPV4;
} else if (*tx_flags & I40E_TX_FLAGS_IPV6) {
cmd |= I40E_TX_DESC_CMD_IIPT_IPV6;
exthdr = ip.hdr + sizeof(*ip.v6);
l4_proto = ip.v6->nexthdr;
if (l4.hdr != exthdr)
ipv6_skip_exthdr(skb, exthdr - skb->data,
&l4_proto, &frag_off);
}
/* compute inner L3 header size */
offset |= ((l4.hdr - ip.hdr) / 4) << I40E_TX_DESC_LENGTH_IPLEN_SHIFT;
/* Enable L4 checksum offloads */
switch (l4_proto) {
case IPPROTO_TCP:
/* enable checksum offloads */
cmd |= I40E_TX_DESC_CMD_L4T_EOFT_TCP;
offset |= l4.tcp->doff << I40E_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
break;
case IPPROTO_SCTP:
/* enable SCTP checksum offload */
cmd |= I40E_TX_DESC_CMD_L4T_EOFT_SCTP;
offset |= (sizeof(struct sctphdr) >> 2) <<
I40E_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
break;
case IPPROTO_UDP:
/* enable UDP checksum offload */
cmd |= I40E_TX_DESC_CMD_L4T_EOFT_UDP;
offset |= (sizeof(struct udphdr) >> 2) <<
I40E_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
break;
default:
if (*tx_flags & I40E_TX_FLAGS_TSO)
return -1;
skb_checksum_help(skb);
return 0;
}
*td_cmd |= cmd;
*td_offset |= offset;
return 1;
}
/**
* i40e_create_tx_ctx Build the Tx context descriptor
* @tx_ring: ring to create the descriptor on
* @cd_type_cmd_tso_mss: Quad Word 1
* @cd_tunneling: Quad Word 0 - bits 0-31
* @cd_l2tag2: Quad Word 0 - bits 32-63
**/
static void i40e_create_tx_ctx(struct i40e_ring *tx_ring,
const u64 cd_type_cmd_tso_mss,
const u32 cd_tunneling, const u32 cd_l2tag2)
{
struct i40e_tx_context_desc *context_desc;
int i = tx_ring->next_to_use;
if ((cd_type_cmd_tso_mss == I40E_TX_DESC_DTYPE_CONTEXT) &&
!cd_tunneling && !cd_l2tag2)
return;
/* grab the next descriptor */
context_desc = I40E_TX_CTXTDESC(tx_ring, i);
i++;
tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;
/* cpu_to_le32 and assign to struct fields */
context_desc->tunneling_params = cpu_to_le32(cd_tunneling);
context_desc->l2tag2 = cpu_to_le16(cd_l2tag2);
context_desc->rsvd = cpu_to_le16(0);
context_desc->type_cmd_tso_mss = cpu_to_le64(cd_type_cmd_tso_mss);
}
/**
* __i40evf_chk_linearize - Check if there are more than 8 buffers per packet
* @skb: send buffer
*
* Note: Our HW can't DMA more than 8 buffers to build a packet on the wire
* and so we need to figure out the cases where we need to linearize the skb.
*
* For TSO we need to count the TSO header and segment payload separately.
* As such we need to check cases where we have 7 fragments or more as we
* can potentially require 9 DMA transactions, 1 for the TSO header, 1 for
* the segment payload in the first descriptor, and another 7 for the
* fragments.
**/
bool __i40evf_chk_linearize(struct sk_buff *skb)
{
const struct skb_frag_struct *frag, *stale;
int nr_frags, sum;
/* no need to check if number of frags is less than 7 */
nr_frags = skb_shinfo(skb)->nr_frags;
if (nr_frags < (I40E_MAX_BUFFER_TXD - 1))
return false;
/* We need to walk through the list and validate that each group
* of 6 fragments totals at least gso_size.
*/
nr_frags -= I40E_MAX_BUFFER_TXD - 2;
frag = &skb_shinfo(skb)->frags[0];
/* Initialize size to the negative value of gso_size minus 1. We
* use this as the worst case scenerio in which the frag ahead
* of us only provides one byte which is why we are limited to 6
* descriptors for a single transmit as the header and previous
* fragment are already consuming 2 descriptors.
*/
sum = 1 - skb_shinfo(skb)->gso_size;
/* Add size of frags 0 through 4 to create our initial sum */
sum += skb_frag_size(frag++);
sum += skb_frag_size(frag++);
sum += skb_frag_size(frag++);
sum += skb_frag_size(frag++);
sum += skb_frag_size(frag++);
/* Walk through fragments adding latest fragment, testing it, and
* then removing stale fragments from the sum.
*/
stale = &skb_shinfo(skb)->frags[0];
for (;;) {
sum += skb_frag_size(frag++);
/* if sum is negative we failed to make sufficient progress */
if (sum < 0)
return true;
if (!nr_frags--)
break;
sum -= skb_frag_size(stale++);
}
return false;
}
/**
* __i40evf_maybe_stop_tx - 2nd level check for tx stop conditions
* @tx_ring: the ring to be checked
* @size: the size buffer we want to assure is available
*
* Returns -EBUSY if a stop is needed, else 0
**/
int __i40evf_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
{
netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);
/* Memory barrier before checking head and tail */
smp_mb();
/* Check again in a case another CPU has just made room available. */
if (likely(I40E_DESC_UNUSED(tx_ring) < size))
return -EBUSY;
/* A reprieve! - use start_queue because it doesn't call schedule */
netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);
++tx_ring->tx_stats.restart_queue;
return 0;
}
/**
* i40evf_tx_map - Build the Tx descriptor
* @tx_ring: ring to send buffer on
* @skb: send buffer
* @first: first buffer info buffer to use
* @tx_flags: collected send information
* @hdr_len: size of the packet header
* @td_cmd: the command field in the descriptor
* @td_offset: offset for checksum or crc
**/
static inline void i40evf_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb,
struct i40e_tx_buffer *first, u32 tx_flags,
const u8 hdr_len, u32 td_cmd, u32 td_offset)
{
unsigned int data_len = skb->data_len;
unsigned int size = skb_headlen(skb);
struct skb_frag_struct *frag;
struct i40e_tx_buffer *tx_bi;
struct i40e_tx_desc *tx_desc;
u16 i = tx_ring->next_to_use;
u32 td_tag = 0;
dma_addr_t dma;
u16 gso_segs;
u16 desc_count = 0;
bool tail_bump = true;
bool do_rs = false;
if (tx_flags & I40E_TX_FLAGS_HW_VLAN) {
td_cmd |= I40E_TX_DESC_CMD_IL2TAG1;
td_tag = (tx_flags & I40E_TX_FLAGS_VLAN_MASK) >>
I40E_TX_FLAGS_VLAN_SHIFT;
}
if (tx_flags & (I40E_TX_FLAGS_TSO | I40E_TX_FLAGS_FSO))
gso_segs = skb_shinfo(skb)->gso_segs;
else
gso_segs = 1;
/* multiply data chunks by size of headers */
first->bytecount = skb->len - hdr_len + (gso_segs * hdr_len);
first->gso_segs = gso_segs;
first->skb = skb;
first->tx_flags = tx_flags;
dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE);
tx_desc = I40E_TX_DESC(tx_ring, i);
tx_bi = first;
for (frag = &skb_shinfo(skb)->frags[0];; frag++) {
unsigned int max_data = I40E_MAX_DATA_PER_TXD_ALIGNED;
if (dma_mapping_error(tx_ring->dev, dma))
goto dma_error;
/* record length, and DMA address */
dma_unmap_len_set(tx_bi, len, size);
dma_unmap_addr_set(tx_bi, dma, dma);
/* align size to end of page */
max_data += -dma & (I40E_MAX_READ_REQ_SIZE - 1);
tx_desc->buffer_addr = cpu_to_le64(dma);
while (unlikely(size > I40E_MAX_DATA_PER_TXD)) {
tx_desc->cmd_type_offset_bsz =
build_ctob(td_cmd, td_offset,
max_data, td_tag);
tx_desc++;
i++;
desc_count++;
if (i == tx_ring->count) {
tx_desc = I40E_TX_DESC(tx_ring, 0);
i = 0;
}
dma += max_data;
size -= max_data;
max_data = I40E_MAX_DATA_PER_TXD_ALIGNED;
tx_desc->buffer_addr = cpu_to_le64(dma);
}
if (likely(!data_len))
break;
tx_desc->cmd_type_offset_bsz = build_ctob(td_cmd, td_offset,
size, td_tag);
tx_desc++;
i++;
desc_count++;
if (i == tx_ring->count) {
tx_desc = I40E_TX_DESC(tx_ring, 0);
i = 0;
}
size = skb_frag_size(frag);
data_len -= size;
dma = skb_frag_dma_map(tx_ring->dev, frag, 0, size,
DMA_TO_DEVICE);
tx_bi = &tx_ring->tx_bi[i];
}
/* set next_to_watch value indicating a packet is present */
first->next_to_watch = tx_desc;
i++;
if (i == tx_ring->count)
i = 0;
tx_ring->next_to_use = i;
netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount);
i40e_maybe_stop_tx(tx_ring, DESC_NEEDED);
/* Algorithm to optimize tail and RS bit setting:
* if xmit_more is supported
* if xmit_more is true
* do not update tail and do not mark RS bit.
* if xmit_more is false and last xmit_more was false
* if every packet spanned less than 4 desc
* then set RS bit on 4th packet and update tail
* on every packet
* else
* update tail and set RS bit on every packet.
* if xmit_more is false and last_xmit_more was true
* update tail and set RS bit.
*
* Optimization: wmb to be issued only in case of tail update.
* Also optimize the Descriptor WB path for RS bit with the same
* algorithm.
*
* Note: If there are less than 4 packets
* pending and interrupts were disabled the service task will
* trigger a force WB.
*/
if (skb->xmit_more &&
!netif_xmit_stopped(txring_txq(tx_ring))) {
tx_ring->flags |= I40E_TXR_FLAGS_LAST_XMIT_MORE_SET;
tail_bump = false;
} else if (!skb->xmit_more &&
!netif_xmit_stopped(txring_txq(tx_ring)) &&
(!(tx_ring->flags & I40E_TXR_FLAGS_LAST_XMIT_MORE_SET)) &&
(tx_ring->packet_stride < WB_STRIDE) &&
(desc_count < WB_STRIDE)) {
tx_ring->packet_stride++;
} else {
tx_ring->packet_stride = 0;
tx_ring->flags &= ~I40E_TXR_FLAGS_LAST_XMIT_MORE_SET;
do_rs = true;
}
if (do_rs)
tx_ring->packet_stride = 0;
tx_desc->cmd_type_offset_bsz =
build_ctob(td_cmd, td_offset, size, td_tag) |
cpu_to_le64((u64)(do_rs ? I40E_TXD_CMD :
I40E_TX_DESC_CMD_EOP) <<
I40E_TXD_QW1_CMD_SHIFT);
/* notify HW of packet */
if (!tail_bump) {
prefetchw(tx_desc + 1);
} else {
/* Force memory writes to complete before letting h/w
* know there are new descriptors to fetch. (Only
* applicable for weak-ordered memory model archs,
* such as IA-64).
*/
wmb();
writel(i, tx_ring->tail);
}
return;
dma_error:
dev_info(tx_ring->dev, "TX DMA map failed\n");
/* clear dma mappings for failed tx_bi map */
for (;;) {
tx_bi = &tx_ring->tx_bi[i];
i40e_unmap_and_free_tx_resource(tx_ring, tx_bi);
if (tx_bi == first)
break;
if (i == 0)
i = tx_ring->count;
i--;
}
tx_ring->next_to_use = i;
}
/**
* i40e_xmit_frame_ring - Sends buffer on Tx ring
* @skb: send buffer
* @tx_ring: ring to send buffer on
*
* Returns NETDEV_TX_OK if sent, else an error code
**/
static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb,
struct i40e_ring *tx_ring)
{
u64 cd_type_cmd_tso_mss = I40E_TX_DESC_DTYPE_CONTEXT;
u32 cd_tunneling = 0, cd_l2tag2 = 0;
struct i40e_tx_buffer *first;
u32 td_offset = 0;
u32 tx_flags = 0;
__be16 protocol;
u32 td_cmd = 0;
u8 hdr_len = 0;
int tso, count;
/* prefetch the data, we'll need it later */
prefetch(skb->data);
count = i40e_xmit_descriptor_count(skb);
if (i40e_chk_linearize(skb, count)) {
if (__skb_linearize(skb))
goto out_drop;
count = i40e_txd_use_count(skb->len);
tx_ring->tx_stats.tx_linearize++;
}
/* need: 1 descriptor per page * PAGE_SIZE/I40E_MAX_DATA_PER_TXD,
* + 1 desc for skb_head_len/I40E_MAX_DATA_PER_TXD,
* + 4 desc gap to avoid the cache line where head is,
* + 1 desc for context descriptor,
* otherwise try next time
*/
if (i40e_maybe_stop_tx(tx_ring, count + 4 + 1)) {
tx_ring->tx_stats.tx_busy++;
return NETDEV_TX_BUSY;
}
/* prepare the xmit flags */
if (i40evf_tx_prepare_vlan_flags(skb, tx_ring, &tx_flags))
goto out_drop;
/* obtain protocol of skb */
protocol = vlan_get_protocol(skb);
/* record the location of the first descriptor for this packet */
first = &tx_ring->tx_bi[tx_ring->next_to_use];
/* setup IPv4/IPv6 offloads */
if (protocol == htons(ETH_P_IP))
tx_flags |= I40E_TX_FLAGS_IPV4;
else if (protocol == htons(ETH_P_IPV6))
tx_flags |= I40E_TX_FLAGS_IPV6;
tso = i40e_tso(skb, &hdr_len, &cd_type_cmd_tso_mss);
if (tso < 0)
goto out_drop;
else if (tso)
tx_flags |= I40E_TX_FLAGS_TSO;
/* Always offload the checksum, since it's in the data descriptor */
tso = i40e_tx_enable_csum(skb, &tx_flags, &td_cmd, &td_offset,
tx_ring, &cd_tunneling);
if (tso < 0)
goto out_drop;
skb_tx_timestamp(skb);
/* always enable CRC insertion offload */
td_cmd |= I40E_TX_DESC_CMD_ICRC;
i40e_create_tx_ctx(tx_ring, cd_type_cmd_tso_mss,
cd_tunneling, cd_l2tag2);
i40evf_tx_map(tx_ring, skb, first, tx_flags, hdr_len,
td_cmd, td_offset);
return NETDEV_TX_OK;
out_drop:
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}
/**
* i40evf_xmit_frame - Selects the correct VSI and Tx queue to send buffer
* @skb: send buffer
* @netdev: network interface device structure
*
* Returns NETDEV_TX_OK if sent, else an error code
**/
netdev_tx_t i40evf_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
{
struct i40evf_adapter *adapter = netdev_priv(netdev);
struct i40e_ring *tx_ring = &adapter->tx_rings[skb->queue_mapping];
/* hardware can't handle really short frames, hardware padding works
* beyond this point
*/
if (unlikely(skb->len < I40E_MIN_TX_LEN)) {
if (skb_pad(skb, I40E_MIN_TX_LEN - skb->len))
return NETDEV_TX_OK;
skb->len = I40E_MIN_TX_LEN;
skb_set_tail_pointer(skb, I40E_MIN_TX_LEN);
}
return i40e_xmit_frame_ring(skb, tx_ring);
}