[Intel-wired-lan] [PATCH 1/1] igb: add XDP support
Alexander Duyck
alexander.duyck at gmail.com
Wed Jul 8 18:20:22 UTC 2020
On Thu, Jun 25, 2020 at 2:25 PM Sven Auhagen <sven.auhagen at voleatech.de> wrote:
>
> Add XDP support to the IGB driver.
> The implementation follows the IXGBE XDP implementation
> closely and I used the following patches as basis:
>
> 1. commit 924708081629 ("ixgbe: add XDP support for pass and drop actions")
> 2. commit 33fdc82f0883 ("ixgbe: add support for XDP_TX action")
> 3. commit ed93a3987128 ("ixgbe: tweak page counting for XDP_REDIRECT")
>
> Due to the hardware constraints of the devices using the
> IGB driver we must share the TX queues with XDP which
> means locking the TX queue also for non XDP cases.
> This comes with a small penalty ~5% in my tests.
So the locking is going to make a huge mess of things for many use
cases. I am not sure slowing down igb in general for one use case will
be all that acceptable. Also I am not sure you are limited to 2 queues
only. I thought that hardware supported up to 4 queues, but only 2
through RSS. You might need to double check the data sheet and
documentation. If you can use 2 additional Tx queues that would spare
you a lot of extra effort.
> I ran tests on an older device to get better numbers.
> Test machine:
>
> Intel(R) Atom(TM) CPU C2338 @ 1.74GHz (2 Cores)
> 2x Intel I211
>
> Routing Original Driver Network Stack: 382 Kpps
> Routing XDP Driver Network Stack: 364 Kpps
>
> Routing XDP Redirect (xdp_fwd_kern): 1.48 Mpps
> XDP Drop: 1.48 Mpps
>
> Using XDP we can achieve line rate forwarding even on
> on older Intel Atom CPU.
>
> Signed-off-by: Sven Auhagen <sven.auhagen at voleatech.de>
> ---
> drivers/net/ethernet/intel/igb/igb.h | 87 +++-
> drivers/net/ethernet/intel/igb/igb_ethtool.c | 8 +-
> drivers/net/ethernet/intel/igb/igb_main.c | 471 +++++++++++++++++--
> 3 files changed, 515 insertions(+), 51 deletions(-)
>
> --- a/drivers/net/ethernet/intel/igb/igb.h
> +++ b/drivers/net/ethernet/intel/igb/igb.h
> @@ -19,6 +19,8 @@
> #include <linux/pci.h>
> #include <linux/mdio.h>
>
> +#include <net/xdp.h>
> +
> struct igb_adapter;
>
> #define E1000_PCS_CFG_IGN_SD 1
> @@ -79,6 +81,12 @@
> #define IGB_I210_RX_LATENCY_100 2213
> #define IGB_I210_RX_LATENCY_1000 448
>
> +/* XDP */
> +#define IGB_XDP_PASS 0
> +#define IGB_XDP_CONSUMED BIT(0)
> +#define IGB_XDP_TX BIT(1)
> +#define IGB_XDP_REDIR BIT(2)
> +
> struct vf_data_storage {
> unsigned char vf_mac_addresses[ETH_ALEN];
> u16 vf_mc_hashes[IGB_MAX_VF_MC_ENTRIES];
> @@ -132,17 +140,62 @@
>
> /* Supported Rx Buffer Sizes */
> #define IGB_RXBUFFER_256 256
> +#define IGB_RXBUFFER_1536 1536
> #define IGB_RXBUFFER_2048 2048
> #define IGB_RXBUFFER_3072 3072
> #define IGB_RX_HDR_LEN IGB_RXBUFFER_256
> #define IGB_TS_HDR_LEN 16
>
> -#define IGB_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
> +/* Attempt to maximize the headroom available for incoming frames. We
> + * use a 2K buffer for receives and need 1536/1534 to store the data for
> + * the frame. This leaves us with 512 bytes of room. From that we need
> + * to deduct the space needed for the shared info and the padding needed
> + * to IP align the frame.
> + *
> + * Note: For cache line sizes 256 or larger this value is going to end
> + * up negative. In these cases we should fall back to the 3K
> + * buffers.
> + */
> #if (PAGE_SIZE < 8192)
> -#define IGB_MAX_FRAME_BUILD_SKB \
> - (SKB_WITH_OVERHEAD(IGB_RXBUFFER_2048) - IGB_SKB_PAD - IGB_TS_HDR_LEN)
> +#define IGB_MAX_2K_FRAME_BUILD_SKB (IGB_RXBUFFER_1536 - NET_IP_ALIGN)
> +#define IGB_2K_TOO_SMALL_WITH_PADDING \
> +((NET_SKB_PAD + IGB_RXBUFFER_1536) > SKB_WITH_OVERHEAD(IGB_RXBUFFER_2048))
> +
> +static inline int igb_compute_pad(int rx_buf_len)
> +{
> + int page_size, pad_size;
> +
> + page_size = ALIGN(rx_buf_len, PAGE_SIZE / 2);
> + pad_size = SKB_WITH_OVERHEAD(page_size) - rx_buf_len;
> +
> + return pad_size;
> +}
> +
> +static inline int igb_skb_pad(void)
> +{
> + int rx_buf_len;
> +
> + /* If a 2K buffer cannot handle a standard Ethernet frame then
> + * optimize padding for a 3K buffer instead of a 1.5K buffer.
> + *
> + * For a 3K buffer we need to add enough padding to allow for
> + * tailroom due to NET_IP_ALIGN possibly shifting us out of
> + * cache-line alignment.
> + */
> + if (IGB_2K_TOO_SMALL_WITH_PADDING)
> + rx_buf_len = IGB_RXBUFFER_3072 + SKB_DATA_ALIGN(NET_IP_ALIGN);
> + else
> + rx_buf_len = IGB_RXBUFFER_1536;
> +
> + /* if needed make room for NET_IP_ALIGN */
> + rx_buf_len -= NET_IP_ALIGN;
> +
> + return igb_compute_pad(rx_buf_len);
> +}
> +
> +#define IGB_SKB_PAD igb_skb_pad()
> #else
> -#define IGB_MAX_FRAME_BUILD_SKB (IGB_RXBUFFER_2048 - IGB_TS_HDR_LEN)
> +#define IGB_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
> #endif
>
> /* How many Rx Buffers do we bundle into one write to the hardware ? */
> @@ -194,13 +247,22 @@
> #define IGB_SFF_ADDRESSING_MODE 0x4
> #define IGB_SFF_8472_UNSUP 0x00
>
> +enum igb_tx_buf_type {
> + IGB_TYPE_SKB = 0,
> + IGB_TYPE_XDP,
> +};
> +
> /* wrapper around a pointer to a socket buffer,
> * so a DMA handle can be stored along with the buffer
> */
> struct igb_tx_buffer {
> union e1000_adv_tx_desc *next_to_watch;
> unsigned long time_stamp;
> - struct sk_buff *skb;
> + enum igb_tx_buf_type type;
> + union {
> + struct sk_buff *skb;
> + struct xdp_frame *xdpf;
> + };
> unsigned int bytecount;
> u16 gso_segs;
> __be16 protocol;
> @@ -248,6 +310,7 @@
> struct igb_ring {
> struct igb_q_vector *q_vector; /* backlink to q_vector */
> struct net_device *netdev; /* back pointer to net_device */
> + struct bpf_prog *xdp_prog;
> struct device *dev; /* device pointer for dma mapping */
> union { /* array of buffer info structs */
> struct igb_tx_buffer *tx_buffer_info;
> @@ -288,6 +351,9 @@
> struct u64_stats_sync rx_syncp;
> };
> };
> + /* lock for TX */
> + spinlock_t tx_lock;
> + struct xdp_rxq_info xdp_rxq;
> } ____cacheline_internodealigned_in_smp;
>
> struct igb_q_vector {
> @@ -339,7 +405,7 @@
> return IGB_RXBUFFER_3072;
>
> if (ring_uses_build_skb(ring))
> - return IGB_MAX_FRAME_BUILD_SKB + IGB_TS_HDR_LEN;
> + return IGB_MAX_2K_FRAME_BUILD_SKB;
> #endif
> return IGB_RXBUFFER_2048;
> }
> @@ -467,6 +533,7 @@
> unsigned long active_vlans[BITS_TO_LONGS(VLAN_N_VID)];
>
> struct net_device *netdev;
> + struct bpf_prog *xdp_prog;
>
> unsigned long state;
> unsigned int flags;
> @@ -644,6 +711,9 @@
> extern char igb_driver_name[];
> extern char igb_driver_version[];
>
> +int igb_xmit_xdp_ring(struct igb_adapter *adapter,
> + struct igb_ring *ring,
> + struct xdp_frame *xdpf);
> int igb_open(struct net_device *netdev);
> int igb_close(struct net_device *netdev);
> int igb_up(struct igb_adapter *);
> @@ -654,7 +724,7 @@
> void igb_write_rss_indir_tbl(struct igb_adapter *);
> int igb_set_spd_dplx(struct igb_adapter *, u32, u8);
> int igb_setup_tx_resources(struct igb_ring *);
> -int igb_setup_rx_resources(struct igb_ring *);
> +int igb_setup_rx_resources(struct igb_ring *, struct igb_adapter *);
> void igb_free_tx_resources(struct igb_ring *);
> void igb_free_rx_resources(struct igb_ring *);
> void igb_configure_tx_ring(struct igb_adapter *, struct igb_ring *);
> --- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
> +++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> @@ -962,8 +962,12 @@
> memcpy(&temp_ring[i], adapter->rx_ring[i],
> sizeof(struct igb_ring));
>
> + /* Clear copied XDP RX-queue info */
> + memset(&temp_ring[i].xdp_rxq, 0,
> + sizeof(temp_ring[i].xdp_rxq));
> +
> temp_ring[i].count = new_rx_count;
> - err = igb_setup_rx_resources(&temp_ring[i]);
> + err = igb_setup_rx_resources(&temp_ring[i], adapter);
> if (err) {
> while (i) {
> i--;
> @@ -1578,7 +1582,7 @@
> rx_ring->netdev = adapter->netdev;
> rx_ring->reg_idx = adapter->vfs_allocated_count;
>
> - if (igb_setup_rx_resources(rx_ring)) {
> + if (igb_setup_rx_resources(rx_ring, adapter)) {
> ret_val = 3;
> goto err_nomem;
> }
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -30,6 +30,8 @@
> #include <linux/if_ether.h>
> #include <linux/aer.h>
> #include <linux/prefetch.h>
> +#include <linux/bpf.h>
> +#include <linux/bpf_trace.h>
> #include <linux/pm_runtime.h>
> #include <linux/etherdevice.h>
> #ifdef CONFIG_IGB_DCA
> @@ -2834,6 +2836,147 @@
> }
> }
>
> +static int igb_xdp_setup(struct net_device *dev, struct bpf_prog *prog)
> +{
> + int i, frame_size = dev->mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
> + struct igb_adapter *adapter = netdev_priv(dev);
> + struct bpf_prog *old_prog;
> + bool running = netif_running(dev);
> + bool need_reset;
> +
> + /* verify igb ring attributes are sufficient for XDP */
> + for (i = 0; i < adapter->num_rx_queues; i++) {
> + struct igb_ring *ring = adapter->rx_ring[i];
> +
> + if (frame_size > igb_rx_bufsz(ring))
> + return -EINVAL;
> + }
> +
> + old_prog = xchg(&adapter->xdp_prog, prog);
> + need_reset = (!!prog != !!old_prog);
> +
> + /* device is up and bpf is added/removed, must setup the RX queues */
> + if (need_reset && running) {
> + igb_close(dev);
> + } else {
> + for (i = 0; i < adapter->num_rx_queues; i++)
> + (void)xchg(&adapter->rx_ring[i]->xdp_prog,
> + adapter->xdp_prog);
> + }
> +
> + if (old_prog)
> + bpf_prog_put(old_prog);
> +
> + /* bpf is just replaced, RXQ and MTU are already setup */
> + if (!need_reset)
> + return 0;
> +
> + if (running)
> + igb_open(dev);
> +
> + return 0;
> +}
> +
> +static int igb_xdp(struct net_device *dev, struct netdev_bpf *xdp)
> +{
> + struct igb_adapter *adapter = netdev_priv(dev);
> +
> + switch (xdp->command) {
> + case XDP_SETUP_PROG:
> + return igb_xdp_setup(dev, xdp->prog);
> + case XDP_QUERY_PROG:
> + xdp->prog_id = adapter->xdp_prog ?
> + adapter->xdp_prog->aux->id : 0;
> + return 0;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +void igb_xdp_ring_update_tail(struct igb_ring *ring)
> +{
> + /* Force memory writes to complete before letting h/w know there
> + * are new descriptors to fetch.
> + */
> + wmb();
> + writel(ring->next_to_use, ring->tail);
> +}
> +
> +static inline struct igb_ring *igb_xdp_tx_queue_mapping(struct igb_adapter *adapter)
> +{
> + unsigned int r_idx = smp_processor_id();
> +
> + if (r_idx >= adapter->num_tx_queues)
> + r_idx = r_idx % adapter->num_tx_queues;
> +
> + return adapter->tx_ring[r_idx];
> +}
> +
> +static int igb_xdp_xmit_back(struct igb_adapter *adapter, struct xdp_buff *xdp)
> +{
> + struct igb_ring *tx_ring;
> + struct xdp_frame *xdpf = xdp_convert_buff_to_frame(xdp);
> + u32 ret;
> +
> + if (unlikely(!xdpf))
> + return IGB_XDP_CONSUMED;
> +
> + /* During program transitions its possible adapter->xdp_prog is assigned
> + * but ring has not been configured yet. In this case simply abort xmit.
> + */
> + tx_ring = adapter->xdp_prog ? igb_xdp_tx_queue_mapping(adapter) : NULL;
> + if (unlikely(!tx_ring))
> + return -ENXIO;
> +
> + spin_lock(&tx_ring->tx_lock);
> + ret = igb_xmit_xdp_ring(adapter, tx_ring, xdpf);
> + spin_unlock(&tx_ring->tx_lock);
> +
> + return ret;
> +}
> +
> +static int igb_xdp_xmit(struct net_device *dev, int n,
> + struct xdp_frame **frames, u32 flags)
> +{
> + struct igb_adapter *adapter = netdev_priv(dev);
> + struct igb_ring *tx_ring;
> + int drops = 0;
> + int i;
> +
> + if (unlikely(test_bit(__IGB_DOWN, &adapter->state)))
> + return -ENETDOWN;
> +
> + if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
> + return -EINVAL;
> +
> + /* During program transitions its possible adapter->xdp_prog is assigned
> + * but ring has not been configured yet. In this case simply abort xmit.
> + */
> + tx_ring = adapter->xdp_prog ? igb_xdp_tx_queue_mapping(adapter) : NULL;
> + if (unlikely(!tx_ring))
> + return -ENXIO;
> +
> + spin_lock(&tx_ring->tx_lock);
> +
> + for (i = 0; i < n; i++) {
> + struct xdp_frame *xdpf = frames[i];
> + int err;
> +
> + err = igb_xmit_xdp_ring(adapter, tx_ring, xdpf);
> + if (err != IGB_XDP_TX) {
> + xdp_return_frame_rx_napi(xdpf);
> + drops++;
> + }
> + }
> +
> + spin_unlock(&tx_ring->tx_lock);
> +
> + if (unlikely(flags & XDP_XMIT_FLUSH))
> + igb_xdp_ring_update_tail(tx_ring);
> +
> + return n - drops;
> +}
> +
> static const struct net_device_ops igb_netdev_ops = {
> .ndo_open = igb_open,
> .ndo_stop = igb_close,
> @@ -2858,6 +3001,8 @@
> .ndo_fdb_add = igb_ndo_fdb_add,
> .ndo_features_check = igb_features_check,
> .ndo_setup_tc = igb_setup_tc,
> + .ndo_bpf = igb_xdp,
> + .ndo_xdp_xmit = igb_xdp_xmit,
> };
>
> /**
> @@ -4060,6 +4205,8 @@
> tx_ring->next_to_use = 0;
> tx_ring->next_to_clean = 0;
>
> + spin_lock_init(&tx_ring->tx_lock);
> +
> return 0;
>
> err:
> @@ -4186,7 +4333,7 @@
> *
> * Returns 0 on success, negative on failure
> **/
> -int igb_setup_rx_resources(struct igb_ring *rx_ring)
> +int igb_setup_rx_resources(struct igb_ring *rx_ring, struct igb_adapter *adapter)
> {
You don't need to add the adapter struct to this if you are just going
to be accessing the netdev.
> struct device *dev = rx_ring->dev;
> int size;
> @@ -4210,6 +4357,13 @@
> rx_ring->next_to_clean = 0;
> rx_ring->next_to_use = 0;
>
> + rx_ring->xdp_prog = adapter->xdp_prog;
> +
If you really need the adapter structure you can always pull it out
via netdev_priv(ring->netdev).
> + /* XDP RX-queue info */
> + if (xdp_rxq_info_reg(&rx_ring->xdp_rxq, adapter->netdev,
> + rx_ring->queue_index) < 0)
So for this bit you could just access ring->netdev, instead of adapter->netdev.
> + goto err;
> +
> return 0;
>
> err:
> @@ -4232,7 +4386,7 @@
> int i, err = 0;
>
> for (i = 0; i < adapter->num_rx_queues; i++) {
> - err = igb_setup_rx_resources(adapter->rx_ring[i]);
> + err = igb_setup_rx_resources(adapter->rx_ring[i], adapter);
> if (err) {
> dev_err(&pdev->dev,
> "Allocation for Rx Queue %u failed\n", i);
> @@ -4514,6 +4668,10 @@
I'm not sure how you generated this diff, but next time if you could
also pass the "p" argument it would make the review much easier as I
would know what functions you are modifying without having to pull up
the code in a separate window.
> int reg_idx = ring->reg_idx;
> u32 rxdctl = 0;
>
> + xdp_rxq_info_unreg_mem_model(&ring->xdp_rxq);
> + WARN_ON(xdp_rxq_info_reg_mem_model(&ring->xdp_rxq,
> + MEM_TYPE_PAGE_SHARED, NULL));
> +
> /* disable the queue */
> wr32(E1000_RXDCTL(reg_idx), 0);
>
> @@ -4565,7 +4723,7 @@
> set_ring_build_skb_enabled(rx_ring);
>
> #if (PAGE_SIZE < 8192)
> - if (adapter->max_frame_size <= IGB_MAX_FRAME_BUILD_SKB)
> + if (adapter->max_frame_size <= IGB_MAX_2K_FRAME_BUILD_SKB)
> return;
>
> set_ring_uses_large_buffer(rx_ring);
> @@ -4718,6 +4876,8 @@
> {
> igb_clean_rx_ring(rx_ring);
>
> + rx_ring->xdp_prog = NULL;
> + xdp_rxq_info_unreg(&rx_ring->xdp_rxq);
> vfree(rx_ring->rx_buffer_info);
> rx_ring->rx_buffer_info = NULL;
>
> @@ -5063,8 +5223,8 @@
>
> #if (PAGE_SIZE < 8192)
> if (!adapter->vfs_allocated_count) {
> - if (adapter->max_frame_size <= IGB_MAX_FRAME_BUILD_SKB)
> - rlpml = IGB_MAX_FRAME_BUILD_SKB;
> + if (adapter->max_frame_size <= IGB_MAX_2K_FRAME_BUILD_SKB)
> + rlpml = IGB_MAX_2K_FRAME_BUILD_SKB;
> }
> #endif
> wr32(E1000_RLPML, rlpml);
This looks like a white space change. Did you mean to change something here?
> @@ -5086,8 +5246,8 @@
> /* enable Rx jumbo frames, restrict as needed to support build_skb */
> vmolr &= ~E1000_VMOLR_RLPML_MASK;
> #if (PAGE_SIZE < 8192)
> - if (adapter->max_frame_size <= IGB_MAX_FRAME_BUILD_SKB)
> - vmolr |= IGB_MAX_FRAME_BUILD_SKB;
> + if (adapter->max_frame_size <= IGB_MAX_2K_FRAME_BUILD_SKB)
> + vmolr |= IGB_MAX_2K_FRAME_BUILD_SKB;
> else
> #endif
> vmolr |= MAX_JUMBO_FRAME_SIZE;
Same here.
> @@ -6087,6 +6247,80 @@
> return -1;
> }
>
> +int igb_xmit_xdp_ring(struct igb_adapter *adapter,
> + struct igb_ring *tx_ring,
> + struct xdp_frame *xdpf)
> +{
> + struct igb_tx_buffer *tx_buffer;
> + union e1000_adv_tx_desc *tx_desc;
> + u32 len, cmd_type, olinfo_status;
> + dma_addr_t dma;
> + u16 i;
> +
> + len = xdpf->len;
> +
> + if (unlikely(!igb_desc_unused(tx_ring)))
> + return IGB_XDP_CONSUMED;
> +
> + dma = dma_map_single(tx_ring->dev, xdpf->data, len, DMA_TO_DEVICE);
> + if (dma_mapping_error(tx_ring->dev, dma))
> + return IGB_XDP_CONSUMED;
> +
> + /* record the location of the first descriptor for this packet */
> + tx_buffer = &tx_ring->tx_buffer_info[tx_ring->next_to_use];
> + tx_buffer->bytecount = len;
> + tx_buffer->gso_segs = 1;
> + tx_buffer->protocol = 0;
> +
> + i = tx_ring->next_to_use;
> + tx_desc = IGB_TX_DESC(tx_ring, i);
> +
> + dma_unmap_len_set(tx_buffer, len, len);
> + dma_unmap_addr_set(tx_buffer, dma, dma);
> + tx_buffer->type = IGB_TYPE_XDP;
> + tx_buffer->xdpf = xdpf;
> +
> + tx_desc->read.buffer_addr = cpu_to_le64(dma);
> +
> + /* put descriptor type bits */
> + cmd_type = E1000_ADVTXD_DTYP_DATA |
> + E1000_ADVTXD_DCMD_DEXT |
> + E1000_ADVTXD_DCMD_IFCS;
> + cmd_type |= len | IGB_TXD_DCMD;
> + tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);
> +
> + olinfo_status = cpu_to_le32(len << E1000_ADVTXD_PAYLEN_SHIFT);
> + /* 82575 requires a unique index per ring */
> + if (test_bit(IGB_RING_FLAG_TX_CTX_IDX, &tx_ring->flags))
> + olinfo_status |= tx_ring->reg_idx << 4;
> +
> + tx_desc->read.olinfo_status = olinfo_status;
> +
> + netdev_tx_sent_queue(txring_txq(tx_ring), tx_buffer->bytecount);
> +
> + /* set the timestamp */
> + tx_buffer->time_stamp = jiffies;
> +
> + /* Avoid any potential race with xdp_xmit and cleanup */
> + smp_wmb();
> +
> + /* set next_to_watch value indicating a packet is present */
> + i++;
> + if (i == tx_ring->count)
> + i = 0;
> +
> + tx_buffer->next_to_watch = tx_desc;
> + tx_ring->next_to_use = i;
> +
> + /* Make sure there is space in the ring for the next send. */
> + igb_maybe_stop_tx(tx_ring, DESC_NEEDED);
> +
> + if (netif_xmit_stopped(txring_txq(tx_ring)) || !netdev_xmit_more())
> + writel(i, tx_ring->tail);
> +
> + return IGB_XDP_TX;
> +}
> +
> netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
> struct igb_ring *tx_ring)
> {
> @@ -6098,6 +6332,8 @@
> __be16 protocol = vlan_get_protocol(skb);
> u8 hdr_len = 0;
>
> + spin_lock_bh(&tx_ring->tx_lock);
> +
> /* need: 1 descriptor per page * PAGE_SIZE/IGB_MAX_DATA_PER_TXD,
> * + 1 desc for skb_headlen/IGB_MAX_DATA_PER_TXD,
> * + 2 desc gap to keep tail from touching head,
So adding locking here is kind of a mess. If you really need locking
it is already in place for the netdev Tx ring itself, why add
additional locking to the driver specific ring structure? Take a look
at HARD_TX_LOCK as that at least provides some additional protections
against lock recursion.
> @@ -6110,11 +6346,13 @@
>
> if (igb_maybe_stop_tx(tx_ring, count + 3)) {
> /* this is a hard error */
> + spin_unlock_bh(&tx_ring->tx_lock);
> return NETDEV_TX_BUSY;
> }
>
> /* record the location of the first descriptor for this packet */
> first = &tx_ring->tx_buffer_info[tx_ring->next_to_use];
> + first->type = IGB_TYPE_SKB;
> first->skb = skb;
> first->bytecount = skb->len;
> first->gso_segs = 1;
> @@ -6155,6 +6393,8 @@
> if (igb_tx_map(tx_ring, first, hdr_len))
> goto cleanup_tx_tstamp;
>
> + spin_unlock_bh(&tx_ring->tx_lock);
> +
> return NETDEV_TX_OK;
>
> out_drop:
> @@ -6171,6 +6411,8 @@
> clear_bit_unlock(__IGB_PTP_TX_IN_PROGRESS, &adapter->state);
> }
>
> + spin_unlock_bh(&tx_ring->tx_lock);
> +
> return NETDEV_TX_OK;
> }
>
> @@ -6257,6 +6499,21 @@
> struct igb_adapter *adapter = netdev_priv(netdev);
> int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
>
> + if (adapter->xdp_prog) {
> + int new_frame_size = new_mtu + ETH_HLEN + ETH_FCS_LEN +
> + VLAN_HLEN;
> + int i;
> +
> + for (i = 0; i < adapter->num_rx_queues; i++) {
> + struct igb_ring *ring = adapter->rx_ring[i];
> +
> + if (new_frame_size > igb_rx_bufsz(ring)) {
> + netdev_warn(adapter->netdev, "Requested MTU size is not supported with XDP\n");
> + return -EINVAL;
> + }
> + }
> + }
> +
> /* adjust max frame to be at least the size of a standard frame */
> if (max_frame < (ETH_FRAME_LEN + ETH_FCS_LEN))
> max_frame = ETH_FRAME_LEN + ETH_FCS_LEN;
> @@ -7784,6 +8041,8 @@
> if (test_bit(__IGB_DOWN, &adapter->state))
> return true;
>
> + spin_lock(&tx_ring->tx_lock);
> +
> tx_buffer = &tx_ring->tx_buffer_info[i];
> tx_desc = IGB_TX_DESC(tx_ring, i);
> i -= tx_ring->count;
Locking at this point should be moot since transmit should no longer be active.
> @@ -7810,7 +8069,10 @@
> total_packets += tx_buffer->gso_segs;
>
> /* free the skb */
> - napi_consume_skb(tx_buffer->skb, napi_budget);
> + if (tx_buffer->type == IGB_TYPE_XDP)
> + xdp_return_frame(tx_buffer->xdpf);
> + else
> + napi_consume_skb(tx_buffer->skb, napi_budget);
>
> /* unmap skb header data */
> dma_unmap_single(tx_ring->dev,
> @@ -7863,6 +8125,9 @@
> total_packets, total_bytes);
> i += tx_ring->count;
> tx_ring->next_to_clean = i;
> +
> + spin_unlock(&tx_ring->tx_lock);
> +
> u64_stats_update_begin(&tx_ring->tx_syncp);
> tx_ring->tx_stats.bytes += total_bytes;
> tx_ring->tx_stats.packets += total_packets;
> @@ -7994,8 +8259,8 @@
> * the pagecnt_bias and page count so that we fully restock the
> * number of references the driver holds.
> */
> - if (unlikely(!pagecnt_bias)) {
> - page_ref_add(page, USHRT_MAX);
> + if (unlikely(pagecnt_bias == 1)) {
> + page_ref_add(page, USHRT_MAX - 1);
> rx_buffer->pagecnt_bias = USHRT_MAX;
> }
>
> @@ -8034,22 +8299,23 @@
>
> static struct sk_buff *igb_construct_skb(struct igb_ring *rx_ring,
> struct igb_rx_buffer *rx_buffer,
> - union e1000_adv_rx_desc *rx_desc,
> - unsigned int size)
> + struct xdp_buff *xdp,
> + union e1000_adv_rx_desc *rx_desc)
> {
> - void *va = page_address(rx_buffer->page) + rx_buffer->page_offset;
> + unsigned int size = xdp->data_end - xdp->data;
> #if (PAGE_SIZE < 8192)
> unsigned int truesize = igb_rx_pg_size(rx_ring) / 2;
> #else
> - unsigned int truesize = SKB_DATA_ALIGN(size);
> + unsigned int truesize = SKB_DATA_ALIGN(xdp->data_end -
> + xdp->data_hard_start);
> #endif
> unsigned int headlen;
> struct sk_buff *skb;
>
> /* prefetch first cache line of first page */
> - prefetch(va);
> + prefetch(xdp->data);
> #if L1_CACHE_BYTES < 128
> - prefetch(va + L1_CACHE_BYTES);
> + prefetch(xdp->data + L1_CACHE_BYTES);
> #endif
>
> /* allocate a skb to store the frags */
> @@ -8058,24 +8324,24 @@
> return NULL;
>
> if (unlikely(igb_test_staterr(rx_desc, E1000_RXDADV_STAT_TSIP))) {
> - igb_ptp_rx_pktstamp(rx_ring->q_vector, va, skb);
> - va += IGB_TS_HDR_LEN;
> + igb_ptp_rx_pktstamp(rx_ring->q_vector, xdp->data, skb);
> + xdp->data += IGB_TS_HDR_LEN;
> size -= IGB_TS_HDR_LEN;
> }
>
> /* Determine available headroom for copy */
> headlen = size;
> if (headlen > IGB_RX_HDR_LEN)
> - headlen = eth_get_headlen(skb->dev, va, IGB_RX_HDR_LEN);
> + headlen = eth_get_headlen(skb->dev, xdp->data, IGB_RX_HDR_LEN);
>
> /* align pull length to size of long to optimize memcpy performance */
> - memcpy(__skb_put(skb, headlen), va, ALIGN(headlen, sizeof(long)));
> + memcpy(__skb_put(skb, headlen), xdp->data, ALIGN(headlen, sizeof(long)));
>
> /* update all of the pointers */
> size -= headlen;
> if (size) {
> skb_add_rx_frag(skb, 0, rx_buffer->page,
> - (va + headlen) - page_address(rx_buffer->page),
> + (xdp->data + headlen) - page_address(rx_buffer->page),
> size, truesize);
> #if (PAGE_SIZE < 8192)
> rx_buffer->page_offset ^= truesize;
> @@ -8091,32 +8357,32 @@
>
> static struct sk_buff *igb_build_skb(struct igb_ring *rx_ring,
> struct igb_rx_buffer *rx_buffer,
> - union e1000_adv_rx_desc *rx_desc,
> - unsigned int size)
> + struct xdp_buff *xdp,
> + union e1000_adv_rx_desc *rx_desc)
> {
> - void *va = page_address(rx_buffer->page) + rx_buffer->page_offset;
> #if (PAGE_SIZE < 8192)
> unsigned int truesize = igb_rx_pg_size(rx_ring) / 2;
> #else
> unsigned int truesize = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) +
> - SKB_DATA_ALIGN(IGB_SKB_PAD + size);
> + SKB_DATA_ALIGN(xdp->data_end -
> + xdp->data_hard_start);
> #endif
> struct sk_buff *skb;
>
> /* prefetch first cache line of first page */
> - prefetch(va);
> + prefetch(xdp->data_meta);
> #if L1_CACHE_BYTES < 128
> - prefetch(va + L1_CACHE_BYTES);
> + prefetch(xdp->data_meta + L1_CACHE_BYTES);
> #endif
>
> /* build an skb around the page buffer */
> - skb = build_skb(va - IGB_SKB_PAD, truesize);
> + skb = build_skb(xdp->data_hard_start, truesize);
> if (unlikely(!skb))
> return NULL;
>
> /* update pointers within the skb to store the data */
> - skb_reserve(skb, IGB_SKB_PAD);
> - __skb_put(skb, size);
> + skb_reserve(skb, xdp->data - xdp->data_hard_start);
> + __skb_put(skb, xdp->data_end - xdp->data);
>
> /* pull timestamp out of packet data */
> if (igb_test_staterr(rx_desc, E1000_RXDADV_STAT_TSIP)) {
> @@ -8134,6 +8400,79 @@
> return skb;
> }
>
> +static struct sk_buff *igb_run_xdp(struct igb_adapter *adapter,
> + struct igb_ring *rx_ring,
> + struct xdp_buff *xdp)
> +{
> + int err, result = IGB_XDP_PASS;
> + struct bpf_prog *xdp_prog;
> + u32 act;
> +
> + rcu_read_lock();
> + xdp_prog = READ_ONCE(rx_ring->xdp_prog);
> +
> + if (!xdp_prog)
> + goto xdp_out;
> +
> + prefetchw(xdp->data_hard_start); /* xdp_frame write */
> +
> + act = bpf_prog_run_xdp(xdp_prog, xdp);
> + switch (act) {
> + case XDP_PASS:
> + break;
> + case XDP_TX:
> + result = igb_xdp_xmit_back(adapter, xdp);
> + break;
> + case XDP_REDIRECT:
> + err = xdp_do_redirect(adapter->netdev, xdp, xdp_prog);
> + if (!err)
> + result = IGB_XDP_REDIR;
> + else
> + result = IGB_XDP_CONSUMED;
> + break;
> + default:
> + bpf_warn_invalid_xdp_action(act);
> + /* fallthrough */
> + case XDP_ABORTED:
> + trace_xdp_exception(rx_ring->netdev, xdp_prog, act);
> + /* fallthrough -- handle aborts by dropping packet */
> + case XDP_DROP:
> + result = IGB_XDP_CONSUMED;
> + break;
> + }
> +xdp_out:
> + rcu_read_unlock();
> + return ERR_PTR(-result);
> +}
> +
> +static unsigned int igb_rx_frame_truesize(struct igb_ring *rx_ring,
> + unsigned int size)
> +{
> + unsigned int truesize;
> +
> +#if (PAGE_SIZE < 8192)
> + truesize = igb_rx_pg_size(rx_ring) / 2; /* Must be power-of-2 */
> +#else
> + truesize = ring_uses_build_skb(rx_ring) ?
> + SKB_DATA_ALIGN(IGB_SKB_PAD + size) +
> + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) :
> + SKB_DATA_ALIGN(size);
I am pretty sure this is buggy, you seem to be adding size twice.
> +#endif
> + return truesize;
> +}
> +
> +static void igb_rx_buffer_flip(struct igb_ring *rx_ring,
> + struct igb_rx_buffer *rx_buffer,
> + unsigned int size)
> +{
> + unsigned int truesize = igb_rx_frame_truesize(rx_ring, size);
> +#if (PAGE_SIZE < 8192)
> + rx_buffer->page_offset ^= truesize;
> +#else
> + rx_buffer->page_offset += truesize;
> +#endif
> +}
> +
> static inline void igb_rx_checksum(struct igb_ring *ring,
> union e1000_adv_rx_desc *rx_desc,
> struct sk_buff *skb)
> @@ -8230,6 +8569,10 @@
> union e1000_adv_rx_desc *rx_desc,
> struct sk_buff *skb)
> {
> + /* XDP packets use error pointer so abort at this point */
> + if (IS_ERR(skb))
> + return true;
> +
> if (unlikely((igb_test_staterr(rx_desc,
> E1000_RXDEXT_ERR_FRAME_ERR_MASK)))) {
> struct net_device *netdev = rx_ring->netdev;
> @@ -8288,6 +8631,11 @@
> skb->protocol = eth_type_trans(skb, rx_ring->netdev);
> }
>
> +static inline unsigned int igb_rx_offset(struct igb_ring *rx_ring)
> +{
> + return ring_uses_build_skb(rx_ring) ? IGB_SKB_PAD : 0;
> +}
> +
> static struct igb_rx_buffer *igb_get_rx_buffer(struct igb_ring *rx_ring,
> const unsigned int size)
> {
> @@ -8332,9 +8680,19 @@
> static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
> {
> struct igb_ring *rx_ring = q_vector->rx.ring;
> + struct igb_adapter *adapter = q_vector->adapter;
> struct sk_buff *skb = rx_ring->skb;
> unsigned int total_bytes = 0, total_packets = 0;
> + unsigned int xdp_xmit = 0;
> u16 cleaned_count = igb_desc_unused(rx_ring);
> + struct xdp_buff xdp;
> +
> + xdp.rxq = &rx_ring->xdp_rxq;
> +
> + /* Frame size depend on rx_ring setup when PAGE_SIZE=4K */
> +#if (PAGE_SIZE < 8192)
> + xdp.frame_sz = igb_rx_frame_truesize(rx_ring, 0);
> +#endif
>
> while (likely(total_packets < budget)) {
> union e1000_adv_rx_desc *rx_desc;
> @@ -8361,13 +8719,38 @@
> rx_buffer = igb_get_rx_buffer(rx_ring, size);
>
> /* retrieve a buffer from the ring */
> - if (skb)
> + if (!skb) {
> + xdp.data = page_address(rx_buffer->page) +
> + rx_buffer->page_offset;
> + xdp.data_meta = xdp.data;
> + xdp.data_hard_start = xdp.data -
> + igb_rx_offset(rx_ring);
> + xdp.data_end = xdp.data + size;
> +#if (PAGE_SIZE > 4096)
> + /* At larger PAGE_SIZE, frame_sz depend on len size */
> + xdp.frame_sz = igb_rx_frame_truesize(rx_ring, size);
> +#endif
> + skb = igb_run_xdp(adapter, rx_ring, &xdp);
> + }
> +
> + if (IS_ERR(skb)) {
> + unsigned int xdp_res = -PTR_ERR(skb);
> +
> + if (xdp_res & (IGB_XDP_TX | IGB_XDP_REDIR)) {
> + xdp_xmit |= xdp_res;
> + igb_rx_buffer_flip(rx_ring, rx_buffer, size);
> + } else {
> + rx_buffer->pagecnt_bias++;
> + }
> + total_packets++;
> + total_bytes += size;
> + } else if (skb)
> igb_add_rx_frag(rx_ring, rx_buffer, skb, size);
> else if (ring_uses_build_skb(rx_ring))
> - skb = igb_build_skb(rx_ring, rx_buffer, rx_desc, size);
> + skb = igb_build_skb(rx_ring, rx_buffer, &xdp, rx_desc);
> else
> skb = igb_construct_skb(rx_ring, rx_buffer,
> - rx_desc, size);
> + &xdp, rx_desc);
>
> /* exit if we failed to retrieve a buffer */
> if (!skb) {
> @@ -8407,6 +8790,15 @@
> /* place incomplete frames back on ring for completion */
> rx_ring->skb = skb;
>
> + if (xdp_xmit & IGB_XDP_REDIR)
> + xdp_do_flush_map();
> +
> + if (xdp_xmit & IGB_XDP_TX) {
> + struct igb_ring *tx_ring = igb_xdp_tx_queue_mapping(adapter);
> +
> + igb_xdp_ring_update_tail(tx_ring);
> + }
> +
> u64_stats_update_begin(&rx_ring->rx_syncp);
> rx_ring->rx_stats.packets += total_packets;
> rx_ring->rx_stats.bytes += total_bytes;
> @@ -8420,11 +8812,6 @@
> return total_packets;
> }
>
> -static inline unsigned int igb_rx_offset(struct igb_ring *rx_ring)
> -{
> - return ring_uses_build_skb(rx_ring) ? IGB_SKB_PAD : 0;
> -}
> -
> static bool igb_alloc_mapped_page(struct igb_ring *rx_ring,
> struct igb_rx_buffer *bi)
> {
> @@ -8461,7 +8848,8 @@
> bi->dma = dma;
> bi->page = page;
> bi->page_offset = igb_rx_offset(rx_ring);
> - bi->pagecnt_bias = 1;
> + page_ref_add(page, USHRT_MAX - 1);
> + bi->pagecnt_bias = USHRT_MAX;
>
> return true;
> }
> --
> 2.20.1
>
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