batman-adv: fix TT sync flag inconsistencies

[mirror_ubuntu-artful-kernel.git] / drivers / net / ethernet / mellanox / mlx4 / en_rx.c

/*
 * Copyright (c) 2007 Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */

#include <net/busy_poll.h>
#include <linux/bpf.h>
#include <linux/bpf_trace.h>
#include <linux/mlx4/cq.h>
#include <linux/slab.h>
#include <linux/mlx4/qp.h>
#include <linux/skbuff.h>
#include <linux/rculist.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/vmalloc.h>
#include <linux/irq.h>

#if IS_ENABLED(CONFIG_IPV6)
#include <net/ip6_checksum.h>
#endif

#include "mlx4_en.h"

static int mlx4_alloc_page(struct mlx4_en_priv *priv,
                           struct mlx4_en_rx_alloc *frag,
                           gfp_t gfp)
{
        struct page *page;
        dma_addr_t dma;

        page = alloc_page(gfp);
        if (unlikely(!page))
                return -ENOMEM;
        dma = dma_map_page(priv->ddev, page, 0, PAGE_SIZE, priv->dma_dir);
        if (unlikely(dma_mapping_error(priv->ddev, dma))) {
                __free_page(page);
                return -ENOMEM;
        }
        frag->page = page;
        frag->dma = dma;
        frag->page_offset = priv->rx_headroom;
        return 0;
}

static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv,
                               struct mlx4_en_rx_ring *ring,
                               struct mlx4_en_rx_desc *rx_desc,
                               struct mlx4_en_rx_alloc *frags,
                               gfp_t gfp)
{
        int i;

        for (i = 0; i < priv->num_frags; i++, frags++) {
                if (!frags->page) {
                        if (mlx4_alloc_page(priv, frags, gfp))
                                return -ENOMEM;
                        ring->rx_alloc_pages++;
                }
                rx_desc->data[i].addr = cpu_to_be64(frags->dma +
                                                    frags->page_offset);
        }
        return 0;
}

static void mlx4_en_free_frag(const struct mlx4_en_priv *priv,
                              struct mlx4_en_rx_alloc *frag)
{
        if (frag->page) {
                dma_unmap_page(priv->ddev, frag->dma,
                               PAGE_SIZE, priv->dma_dir);
                __free_page(frag->page);
        }
        /* We need to clear all fields, otherwise a change of priv->log_rx_info
         * could lead to see garbage later in frag->page.
         */
        memset(frag, 0, sizeof(*frag));
}

static void mlx4_en_init_rx_desc(const struct mlx4_en_priv *priv,
                                 struct mlx4_en_rx_ring *ring, int index)
{
        struct mlx4_en_rx_desc *rx_desc = ring->buf + ring->stride * index;
        int possible_frags;
        int i;

        /* Set size and memtype fields */
        for (i = 0; i < priv->num_frags; i++) {
                rx_desc->data[i].byte_count =
                        cpu_to_be32(priv->frag_info[i].frag_size);
                rx_desc->data[i].lkey = cpu_to_be32(priv->mdev->mr.key);
        }

        /* If the number of used fragments does not fill up the ring stride,
         * remaining (unused) fragments must be padded with null address/size
         * and a special memory key */
        possible_frags = (ring->stride - sizeof(struct mlx4_en_rx_desc)) / DS_SIZE;
        for (i = priv->num_frags; i < possible_frags; i++) {
                rx_desc->data[i].byte_count = 0;
                rx_desc->data[i].lkey = cpu_to_be32(MLX4_EN_MEMTYPE_PAD);
                rx_desc->data[i].addr = 0;
        }
}

static int mlx4_en_prepare_rx_desc(struct mlx4_en_priv *priv,
                                   struct mlx4_en_rx_ring *ring, int index,
                                   gfp_t gfp)
{
        struct mlx4_en_rx_desc *rx_desc = ring->buf +
                (index << ring->log_stride);
        struct mlx4_en_rx_alloc *frags = ring->rx_info +
                                        (index << priv->log_rx_info);
        if (likely(ring->page_cache.index > 0)) {
                /* XDP uses a single page per frame */
                if (!frags->page) {
                        ring->page_cache.index--;
                        frags->page = ring->page_cache.buf[ring->page_cache.index].page;
                        frags->dma  = ring->page_cache.buf[ring->page_cache.index].dma;
                }
                frags->page_offset = XDP_PACKET_HEADROOM;
                rx_desc->data[0].addr = cpu_to_be64(frags->dma +
                                                    XDP_PACKET_HEADROOM);
                return 0;
        }

        return mlx4_en_alloc_frags(priv, ring, rx_desc, frags, gfp);
}

static bool mlx4_en_is_ring_empty(const struct mlx4_en_rx_ring *ring)
{
        return ring->prod == ring->cons;
}

static inline void mlx4_en_update_rx_prod_db(struct mlx4_en_rx_ring *ring)
{
        *ring->wqres.db.db = cpu_to_be32(ring->prod & 0xffff);
}

/* slow path */
static void mlx4_en_free_rx_desc(const struct mlx4_en_priv *priv,
                                 struct mlx4_en_rx_ring *ring,
                                 int index)
{
        struct mlx4_en_rx_alloc *frags;
        int nr;

        frags = ring->rx_info + (index << priv->log_rx_info);
        for (nr = 0; nr < priv->num_frags; nr++) {
                en_dbg(DRV, priv, "Freeing fragment:%d\n", nr);
                mlx4_en_free_frag(priv, frags + nr);
        }
}

/* Function not in fast-path */
static int mlx4_en_fill_rx_buffers(struct mlx4_en_priv *priv)
{
        struct mlx4_en_rx_ring *ring;
        int ring_ind;
        int buf_ind;
        int new_size;

        for (buf_ind = 0; buf_ind < priv->prof->rx_ring_size; buf_ind++) {
                for (ring_ind = 0; ring_ind < priv->rx_ring_num; ring_ind++) {
                        ring = priv->rx_ring[ring_ind];

                        if (mlx4_en_prepare_rx_desc(priv, ring,
                                                    ring->actual_size,
                                                    GFP_KERNEL | __GFP_COLD)) {
                                if (ring->actual_size < MLX4_EN_MIN_RX_SIZE) {
                                        en_err(priv, "Failed to allocate enough rx buffers\n");
                                        return -ENOMEM;
                                } else {
                                        new_size = rounddown_pow_of_two(ring->actual_size);
                                        en_warn(priv, "Only %d buffers allocated reducing ring size to %d\n",
                                                ring->actual_size, new_size);
                                        goto reduce_rings;
                                }
                        }
                        ring->actual_size++;
                        ring->prod++;
                }
        }
        return 0;

reduce_rings:
        for (ring_ind = 0; ring_ind < priv->rx_ring_num; ring_ind++) {
                ring = priv->rx_ring[ring_ind];
                while (ring->actual_size > new_size) {
                        ring->actual_size--;
                        ring->prod--;
                        mlx4_en_free_rx_desc(priv, ring, ring->actual_size);
                }
        }

        return 0;
}

static void mlx4_en_free_rx_buf(struct mlx4_en_priv *priv,
                                struct mlx4_en_rx_ring *ring)
{
        int index;

        en_dbg(DRV, priv, "Freeing Rx buf - cons:%d prod:%d\n",
               ring->cons, ring->prod);

        /* Unmap and free Rx buffers */
        for (index = 0; index < ring->size; index++) {
                en_dbg(DRV, priv, "Processing descriptor:%d\n", index);
                mlx4_en_free_rx_desc(priv, ring, index);
        }
        ring->cons = 0;
        ring->prod = 0;
}

void mlx4_en_set_num_rx_rings(struct mlx4_en_dev *mdev)
{
        int i;
        int num_of_eqs;
        int num_rx_rings;
        struct mlx4_dev *dev = mdev->dev;

        mlx4_foreach_port(i, dev, MLX4_PORT_TYPE_ETH) {
                num_of_eqs = max_t(int, MIN_RX_RINGS,
                                   min_t(int,
                                         mlx4_get_eqs_per_port(mdev->dev, i),
                                         DEF_RX_RINGS));

                num_rx_rings = mlx4_low_memory_profile() ? MIN_RX_RINGS :
                        min_t(int, num_of_eqs,
                              netif_get_num_default_rss_queues());
                mdev->profile.prof[i].rx_ring_num =
                        rounddown_pow_of_two(num_rx_rings);
        }
}

int mlx4_en_create_rx_ring(struct mlx4_en_priv *priv,
                           struct mlx4_en_rx_ring **pring,
                           u32 size, u16 stride, int node)
{
        struct mlx4_en_dev *mdev = priv->mdev;
        struct mlx4_en_rx_ring *ring;
        int err = -ENOMEM;
        int tmp;

        ring = kzalloc_node(sizeof(*ring), GFP_KERNEL, node);
        if (!ring) {
                ring = kzalloc(sizeof(*ring), GFP_KERNEL);
                if (!ring) {
                        en_err(priv, "Failed to allocate RX ring structure\n");
                        return -ENOMEM;
                }
        }

        ring->prod = 0;
        ring->cons = 0;
        ring->size = size;
        ring->size_mask = size - 1;
        ring->stride = stride;
        ring->log_stride = ffs(ring->stride) - 1;
        ring->buf_size = ring->size * ring->stride + TXBB_SIZE;

        tmp = size * roundup_pow_of_two(MLX4_EN_MAX_RX_FRAGS *
                                        sizeof(struct mlx4_en_rx_alloc));
        ring->rx_info = vzalloc_node(tmp, node);
        if (!ring->rx_info) {
                ring->rx_info = vzalloc(tmp);
                if (!ring->rx_info) {
                        err = -ENOMEM;
                        goto err_ring;
                }
        }

        en_dbg(DRV, priv, "Allocated rx_info ring at addr:%p size:%d\n",
                 ring->rx_info, tmp);

        /* Allocate HW buffers on provided NUMA node */
        set_dev_node(&mdev->dev->persist->pdev->dev, node);
        err = mlx4_alloc_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
        set_dev_node(&mdev->dev->persist->pdev->dev, mdev->dev->numa_node);
        if (err)
                goto err_info;

        ring->buf = ring->wqres.buf.direct.buf;

        ring->hwtstamp_rx_filter = priv->hwtstamp_config.rx_filter;

        *pring = ring;
        return 0;

err_info:
        vfree(ring->rx_info);
        ring->rx_info = NULL;
err_ring:
        kfree(ring);
        *pring = NULL;

        return err;
}

int mlx4_en_activate_rx_rings(struct mlx4_en_priv *priv)
{
        struct mlx4_en_rx_ring *ring;
        int i;
        int ring_ind;
        int err;
        int stride = roundup_pow_of_two(sizeof(struct mlx4_en_rx_desc) +
                                        DS_SIZE * priv->num_frags);

        for (ring_ind = 0; ring_ind < priv->rx_ring_num; ring_ind++) {
                ring = priv->rx_ring[ring_ind];

                ring->prod = 0;
                ring->cons = 0;
                ring->actual_size = 0;
                ring->cqn = priv->rx_cq[ring_ind]->mcq.cqn;

                ring->stride = stride;
                if (ring->stride <= TXBB_SIZE) {
                        /* Stamp first unused send wqe */
                        __be32 *ptr = (__be32 *)ring->buf;
                        __be32 stamp = cpu_to_be32(1 << STAMP_SHIFT);
                        *ptr = stamp;
                        /* Move pointer to start of rx section */
                        ring->buf += TXBB_SIZE;
                }

                ring->log_stride = ffs(ring->stride) - 1;
                ring->buf_size = ring->size * ring->stride;

                memset(ring->buf, 0, ring->buf_size);
                mlx4_en_update_rx_prod_db(ring);

                /* Initialize all descriptors */
                for (i = 0; i < ring->size; i++)
                        mlx4_en_init_rx_desc(priv, ring, i);
        }
        err = mlx4_en_fill_rx_buffers(priv);
        if (err)
                goto err_buffers;

        for (ring_ind = 0; ring_ind < priv->rx_ring_num; ring_ind++) {
                ring = priv->rx_ring[ring_ind];

                ring->size_mask = ring->actual_size - 1;
                mlx4_en_update_rx_prod_db(ring);
        }

        return 0;

err_buffers:
        for (ring_ind = 0; ring_ind < priv->rx_ring_num; ring_ind++)
                mlx4_en_free_rx_buf(priv, priv->rx_ring[ring_ind]);

        ring_ind = priv->rx_ring_num - 1;
        while (ring_ind >= 0) {
                if (priv->rx_ring[ring_ind]->stride <= TXBB_SIZE)
                        priv->rx_ring[ring_ind]->buf -= TXBB_SIZE;
                ring_ind--;
        }
        return err;
}

/* We recover from out of memory by scheduling our napi poll
 * function (mlx4_en_process_cq), which tries to allocate
 * all missing RX buffers (call to mlx4_en_refill_rx_buffers).
 */
void mlx4_en_recover_from_oom(struct mlx4_en_priv *priv)
{
        int ring;

        if (!priv->port_up)
                return;

        for (ring = 0; ring < priv->rx_ring_num; ring++) {
                if (mlx4_en_is_ring_empty(priv->rx_ring[ring])) {
                        local_bh_disable();
                        napi_reschedule(&priv->rx_cq[ring]->napi);
                        local_bh_enable();
                }
        }
}

/* When the rx ring is running in page-per-packet mode, a released frame can go
 * directly into a small cache, to avoid unmapping or touching the page
 * allocator. In bpf prog performance scenarios, buffers are either forwarded
 * or dropped, never converted to skbs, so every page can come directly from
 * this cache when it is sized to be a multiple of the napi budget.
 */
bool mlx4_en_rx_recycle(struct mlx4_en_rx_ring *ring,
                        struct mlx4_en_rx_alloc *frame)
{
        struct mlx4_en_page_cache *cache = &ring->page_cache;

        if (cache->index >= MLX4_EN_CACHE_SIZE)
                return false;

        cache->buf[cache->index].page = frame->page;
        cache->buf[cache->index].dma = frame->dma;
        cache->index++;
        return true;
}

void mlx4_en_destroy_rx_ring(struct mlx4_en_priv *priv,
                             struct mlx4_en_rx_ring **pring,
                             u32 size, u16 stride)
{
        struct mlx4_en_dev *mdev = priv->mdev;
        struct mlx4_en_rx_ring *ring = *pring;
        struct bpf_prog *old_prog;

        old_prog = rcu_dereference_protected(
                                        ring->xdp_prog,
                                        lockdep_is_held(&mdev->state_lock));
        if (old_prog)
                bpf_prog_put(old_prog);
        mlx4_free_hwq_res(mdev->dev, &ring->wqres, size * stride + TXBB_SIZE);
        vfree(ring->rx_info);
        ring->rx_info = NULL;
        kfree(ring);
        *pring = NULL;
}

void mlx4_en_deactivate_rx_ring(struct mlx4_en_priv *priv,
                                struct mlx4_en_rx_ring *ring)
{
        int i;

        for (i = 0; i < ring->page_cache.index; i++) {
                dma_unmap_page(priv->ddev, ring->page_cache.buf[i].dma,
                               PAGE_SIZE, priv->dma_dir);
                put_page(ring->page_cache.buf[i].page);
        }
        ring->page_cache.index = 0;
        mlx4_en_free_rx_buf(priv, ring);
        if (ring->stride <= TXBB_SIZE)
                ring->buf -= TXBB_SIZE;
}


static int mlx4_en_complete_rx_desc(struct mlx4_en_priv *priv,
                                    struct mlx4_en_rx_alloc *frags,
                                    struct sk_buff *skb,
                                    int length)
{
        const struct mlx4_en_frag_info *frag_info = priv->frag_info;
        unsigned int truesize = 0;
        int nr, frag_size;
        struct page *page;
        dma_addr_t dma;
        bool release;

        /* Collect used fragments while replacing them in the HW descriptors */
        for (nr = 0;; frags++) {
                frag_size = min_t(int, length, frag_info->frag_size);

                page = frags->page;
                if (unlikely(!page))
                        goto fail;

                dma = frags->dma;
                dma_sync_single_range_for_cpu(priv->ddev, dma, frags->page_offset,
                                              frag_size, priv->dma_dir);

                __skb_fill_page_desc(skb, nr, page, frags->page_offset,
                                     frag_size);

                truesize += frag_info->frag_stride;
                if (frag_info->frag_stride == PAGE_SIZE / 2) {
                        frags->page_offset ^= PAGE_SIZE / 2;
                        release = page_count(page) != 1 ||
                                  page_is_pfmemalloc(page) ||
                                  page_to_nid(page) != numa_mem_id();
                } else {
                        u32 sz_align = ALIGN(frag_size, SMP_CACHE_BYTES);

                        frags->page_offset += sz_align;
                        release = frags->page_offset + frag_info->frag_size > PAGE_SIZE;
                }
                if (release) {
                        dma_unmap_page(priv->ddev, dma, PAGE_SIZE, priv->dma_dir);
                        frags->page = NULL;
                } else {
                        page_ref_inc(page);
                }

                nr++;
                length -= frag_size;
                if (!length)
                        break;
                frag_info++;
        }
        skb->truesize += truesize;
        return nr;

fail:
        while (nr > 0) {
                nr--;
                __skb_frag_unref(skb_shinfo(skb)->frags + nr);
        }
        return 0;
}

static void validate_loopback(struct mlx4_en_priv *priv, void *va)
{
        const unsigned char *data = va + ETH_HLEN;
        int i;

        for (i = 0; i < MLX4_LOOPBACK_TEST_PAYLOAD; i++) {
                if (data[i] != (unsigned char)i)
                        return;
        }
        /* Loopback found */
        priv->loopback_ok = 1;
}

static void mlx4_en_refill_rx_buffers(struct mlx4_en_priv *priv,
                                      struct mlx4_en_rx_ring *ring)
{
        u32 missing = ring->actual_size - (ring->prod - ring->cons);

        /* Try to batch allocations, but not too much. */
        if (missing < 8)
                return;
        do {
                if (mlx4_en_prepare_rx_desc(priv, ring,
                                            ring->prod & ring->size_mask,
                                            GFP_ATOMIC | __GFP_COLD |
                                            __GFP_MEMALLOC))
                        break;
                ring->prod++;
        } while (likely(--missing));

        mlx4_en_update_rx_prod_db(ring);
}

/* When hardware doesn't strip the vlan, we need to calculate the checksum
 * over it and add it to the hardware's checksum calculation
 */
static inline __wsum get_fixed_vlan_csum(__wsum hw_checksum,
                                         struct vlan_hdr *vlanh)
{
        return csum_add(hw_checksum, *(__wsum *)vlanh);
}

/* Although the stack expects checksum which doesn't include the pseudo
 * header, the HW adds it. To address that, we are subtracting the pseudo
 * header checksum from the checksum value provided by the HW.
 */
static void get_fixed_ipv4_csum(__wsum hw_checksum, struct sk_buff *skb,
                                struct iphdr *iph)
{
        __u16 length_for_csum = 0;
        __wsum csum_pseudo_header = 0;

        length_for_csum = (be16_to_cpu(iph->tot_len) - (iph->ihl << 2));
        csum_pseudo_header = csum_tcpudp_nofold(iph->saddr, iph->daddr,
                                                length_for_csum, iph->protocol, 0);
        skb->csum = csum_sub(hw_checksum, csum_pseudo_header);
}

#if IS_ENABLED(CONFIG_IPV6)
/* In IPv6 packets, besides subtracting the pseudo header checksum,
 * we also compute/add the IP header checksum which
 * is not added by the HW.
 */
static int get_fixed_ipv6_csum(__wsum hw_checksum, struct sk_buff *skb,
                               struct ipv6hdr *ipv6h)
{
        __wsum csum_pseudo_hdr = 0;

        if (unlikely(ipv6h->nexthdr == IPPROTO_FRAGMENT ||
                     ipv6h->nexthdr == IPPROTO_HOPOPTS))
                return -1;
        hw_checksum = csum_add(hw_checksum, (__force __wsum)htons(ipv6h->nexthdr));

        csum_pseudo_hdr = csum_partial(&ipv6h->saddr,
                                       sizeof(ipv6h->saddr) + sizeof(ipv6h->daddr), 0);
        csum_pseudo_hdr = csum_add(csum_pseudo_hdr, (__force __wsum)ipv6h->payload_len);
        csum_pseudo_hdr = csum_add(csum_pseudo_hdr, (__force __wsum)ntohs(ipv6h->nexthdr));

        skb->csum = csum_sub(hw_checksum, csum_pseudo_hdr);
        skb->csum = csum_add(skb->csum, csum_partial(ipv6h, sizeof(struct ipv6hdr), 0));
        return 0;
}
#endif
static int check_csum(struct mlx4_cqe *cqe, struct sk_buff *skb, void *va,
                      netdev_features_t dev_features)
{
        __wsum hw_checksum = 0;

        void *hdr = (u8 *)va + sizeof(struct ethhdr);

        hw_checksum = csum_unfold((__force __sum16)cqe->checksum);

        if (cqe->vlan_my_qpn & cpu_to_be32(MLX4_CQE_CVLAN_PRESENT_MASK) &&
            !(dev_features & NETIF_F_HW_VLAN_CTAG_RX)) {
                hw_checksum = get_fixed_vlan_csum(hw_checksum, hdr);
                hdr += sizeof(struct vlan_hdr);
        }

        if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV4))
                get_fixed_ipv4_csum(hw_checksum, skb, hdr);
#if IS_ENABLED(CONFIG_IPV6)
        else if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV6))
                if (unlikely(get_fixed_ipv6_csum(hw_checksum, skb, hdr)))
                        return -1;
#endif
        return 0;
}

int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int budget)
{
        struct mlx4_en_priv *priv = netdev_priv(dev);
        int factor = priv->cqe_factor;
        struct mlx4_en_rx_ring *ring;
        struct bpf_prog *xdp_prog;
        int cq_ring = cq->ring;
        bool doorbell_pending;
        struct mlx4_cqe *cqe;
        int polled = 0;
        int index;

        if (unlikely(!priv->port_up))
                return 0;

        if (unlikely(budget <= 0))
                return polled;

        ring = priv->rx_ring[cq_ring];

        /* Protect accesses to: ring->xdp_prog, priv->mac_hash list */
        rcu_read_lock();
        xdp_prog = rcu_dereference(ring->xdp_prog);
        doorbell_pending = 0;

        /* We assume a 1:1 mapping between CQEs and Rx descriptors, so Rx
         * descriptor offset can be deduced from the CQE index instead of
         * reading 'cqe->index' */
        index = cq->mcq.cons_index & ring->size_mask;
        cqe = mlx4_en_get_cqe(cq->buf, index, priv->cqe_size) + factor;

        /* Process all completed CQEs */
        while (XNOR(cqe->owner_sr_opcode & MLX4_CQE_OWNER_MASK,
                    cq->mcq.cons_index & cq->size)) {
                struct mlx4_en_rx_alloc *frags;
                enum pkt_hash_types hash_type;
                struct sk_buff *skb;
                unsigned int length;
                int ip_summed;
                void *va;
                int nr;

                frags = ring->rx_info + (index << priv->log_rx_info);
                va = page_address(frags[0].page) + frags[0].page_offset;
                prefetchw(va);
                /*
                 * make sure we read the CQE after we read the ownership bit
                 */
                dma_rmb();

                /* Drop packet on bad receive or bad checksum */
                if (unlikely((cqe->owner_sr_opcode & MLX4_CQE_OPCODE_MASK) ==
                                                MLX4_CQE_OPCODE_ERROR)) {
                        en_err(priv, "CQE completed in error - vendor syndrom:%d syndrom:%d\n",
                               ((struct mlx4_err_cqe *)cqe)->vendor_err_syndrome,
                               ((struct mlx4_err_cqe *)cqe)->syndrome);
                        goto next;
                }
                if (unlikely(cqe->badfcs_enc & MLX4_CQE_BAD_FCS)) {
                        en_dbg(RX_ERR, priv, "Accepted frame with bad FCS\n");
                        goto next;
                }

                /* Check if we need to drop the packet if SRIOV is not enabled
                 * and not performing the selftest or flb disabled
                 */
                if (priv->flags & MLX4_EN_FLAG_RX_FILTER_NEEDED) {
                        const struct ethhdr *ethh = va;
                        dma_addr_t dma;
                        /* Get pointer to first fragment since we haven't
                         * skb yet and cast it to ethhdr struct
                         */
                        dma = frags[0].dma + frags[0].page_offset;
                        dma_sync_single_for_cpu(priv->ddev, dma, sizeof(*ethh),
                                                DMA_FROM_DEVICE);

                        if (is_multicast_ether_addr(ethh->h_dest)) {
                                struct mlx4_mac_entry *entry;
                                struct hlist_head *bucket;
                                unsigned int mac_hash;

                                /* Drop the packet, since HW loopback-ed it */
                                mac_hash = ethh->h_source[MLX4_EN_MAC_HASH_IDX];
                                bucket = &priv->mac_hash[mac_hash];
                                hlist_for_each_entry_rcu(entry, bucket, hlist) {
                                        if (ether_addr_equal_64bits(entry->mac,
                                                                    ethh->h_source))
                                                goto next;
                                }
                        }
                }

                if (unlikely(priv->validate_loopback)) {
                        validate_loopback(priv, va);
                        goto next;
                }

                /*
                 * Packet is OK - process it.
                 */
                length = be32_to_cpu(cqe->byte_cnt);
                length -= ring->fcs_del;

                /* A bpf program gets first chance to drop the packet. It may
                 * read bytes but not past the end of the frag.
                 */
                if (xdp_prog) {
                        struct xdp_buff xdp;
                        dma_addr_t dma;
                        void *orig_data;
                        u32 act;

                        dma = frags[0].dma + frags[0].page_offset;
                        dma_sync_single_for_cpu(priv->ddev, dma,
                                                priv->frag_info[0].frag_size,
                                                DMA_FROM_DEVICE);

                        xdp.data_hard_start = va - frags[0].page_offset;
                        xdp.data = va;
                        xdp.data_end = xdp.data + length;
                        orig_data = xdp.data;

                        act = bpf_prog_run_xdp(xdp_prog, &xdp);

                        if (xdp.data != orig_data) {
                                length = xdp.data_end - xdp.data;
                                frags[0].page_offset = xdp.data -
                                        xdp.data_hard_start;
                                va = xdp.data;
                        }

                        switch (act) {
                        case XDP_PASS:
                                break;
                        case XDP_TX:
                                if (likely(!mlx4_en_xmit_frame(ring, frags, dev,
                                                        length, cq_ring,
                                                        &doorbell_pending))) {
                                        frags[0].page = NULL;
                                        goto next;
                                }
                                trace_xdp_exception(dev, xdp_prog, act);
                                goto xdp_drop_no_cnt; /* Drop on xmit failure */
                        default:
                                bpf_warn_invalid_xdp_action(act);
                        case XDP_ABORTED:
                                trace_xdp_exception(dev, xdp_prog, act);
                        case XDP_DROP:
                                ring->xdp_drop++;
xdp_drop_no_cnt:
                                goto next;
                        }
                }

                ring->bytes += length;
                ring->packets++;

                skb = napi_get_frags(&cq->napi);
                if (unlikely(!skb))
                        goto next;

                if (unlikely(ring->hwtstamp_rx_filter == HWTSTAMP_FILTER_ALL)) {
                        u64 timestamp = mlx4_en_get_cqe_ts(cqe);

                        mlx4_en_fill_hwtstamps(priv->mdev, skb_hwtstamps(skb),
                                               timestamp);
                }
                skb_record_rx_queue(skb, cq_ring);

                if (likely(dev->features & NETIF_F_RXCSUM)) {
                        if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_TCP |
                                                      MLX4_CQE_STATUS_UDP)) {
                                if ((cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPOK)) &&
                                    cqe->checksum == cpu_to_be16(0xffff)) {
                                        bool l2_tunnel = (dev->hw_enc_features & NETIF_F_RXCSUM) &&
                                                (cqe->vlan_my_qpn & cpu_to_be32(MLX4_CQE_L2_TUNNEL));

                                        ip_summed = CHECKSUM_UNNECESSARY;
                                        hash_type = PKT_HASH_TYPE_L4;
                                        if (l2_tunnel)
                                                skb->csum_level = 1;
                                        ring->csum_ok++;
                                } else {
                                        goto csum_none;
                                }
                        } else {
                                if (priv->flags & MLX4_EN_FLAG_RX_CSUM_NON_TCP_UDP &&
                                    (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV4 |
                                                               MLX4_CQE_STATUS_IPV6))) {
                                        if (check_csum(cqe, skb, va, dev->features)) {
                                                goto csum_none;
                                        } else {
                                                ip_summed = CHECKSUM_COMPLETE;
                                                hash_type = PKT_HASH_TYPE_L3;
                                                ring->csum_complete++;
                                        }
                                } else {
                                        goto csum_none;
                                }
                        }
                } else {
csum_none:
                        ip_summed = CHECKSUM_NONE;
                        hash_type = PKT_HASH_TYPE_L3;
                        ring->csum_none++;
                }
                skb->ip_summed = ip_summed;
                if (dev->features & NETIF_F_RXHASH)
                        skb_set_hash(skb,
                                     be32_to_cpu(cqe->immed_rss_invalid),
                                     hash_type);

                if ((cqe->vlan_my_qpn &
                     cpu_to_be32(MLX4_CQE_CVLAN_PRESENT_MASK)) &&
                    (dev->features & NETIF_F_HW_VLAN_CTAG_RX))
                        __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
                                               be16_to_cpu(cqe->sl_vid));
                else if ((cqe->vlan_my_qpn &
                          cpu_to_be32(MLX4_CQE_SVLAN_PRESENT_MASK)) &&
                         (dev->features & NETIF_F_HW_VLAN_STAG_RX))
                        __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021AD),
                                               be16_to_cpu(cqe->sl_vid));

                nr = mlx4_en_complete_rx_desc(priv, frags, skb, length);
                if (likely(nr)) {
                        skb_shinfo(skb)->nr_frags = nr;
                        skb->len = length;
                        skb->data_len = length;
                        napi_gro_frags(&cq->napi);
                } else {
                        skb->vlan_tci = 0;
                        skb_clear_hash(skb);
                }
next:
                ++cq->mcq.cons_index;
                index = (cq->mcq.cons_index) & ring->size_mask;
                cqe = mlx4_en_get_cqe(cq->buf, index, priv->cqe_size) + factor;
                if (unlikely(++polled == budget))
                        break;
        }

        rcu_read_unlock();

        if (likely(polled)) {
                if (doorbell_pending) {
                        priv->tx_cq[TX_XDP][cq_ring]->xdp_busy = true;
                        mlx4_en_xmit_doorbell(priv->tx_ring[TX_XDP][cq_ring]);
                }

                mlx4_cq_set_ci(&cq->mcq);
                wmb(); /* ensure HW sees CQ consumer before we post new buffers */
                ring->cons = cq->mcq.cons_index;
        }
        AVG_PERF_COUNTER(priv->pstats.rx_coal_avg, polled);

        mlx4_en_refill_rx_buffers(priv, ring);

        return polled;
}


void mlx4_en_rx_irq(struct mlx4_cq *mcq)
{
        struct mlx4_en_cq *cq = container_of(mcq, struct mlx4_en_cq, mcq);
        struct mlx4_en_priv *priv = netdev_priv(cq->dev);

        if (likely(priv->port_up))
                napi_schedule_irqoff(&cq->napi);
        else
                mlx4_en_arm_cq(priv, cq);
}

/* Rx CQ polling - called by NAPI */
int mlx4_en_poll_rx_cq(struct napi_struct *napi, int budget)
{
        struct mlx4_en_cq *cq = container_of(napi, struct mlx4_en_cq, napi);
        struct net_device *dev = cq->dev;
        struct mlx4_en_priv *priv = netdev_priv(dev);
        struct mlx4_en_cq *xdp_tx_cq = NULL;
        bool clean_complete = true;
        int done;

        if (priv->tx_ring_num[TX_XDP]) {
                xdp_tx_cq = priv->tx_cq[TX_XDP][cq->ring];
                if (xdp_tx_cq->xdp_busy) {
                        clean_complete = mlx4_en_process_tx_cq(dev, xdp_tx_cq,
                                                               budget);
                        xdp_tx_cq->xdp_busy = !clean_complete;
                }
        }

        done = mlx4_en_process_rx_cq(dev, cq, budget);

        /* If we used up all the quota - we're probably not done yet... */
        if (done == budget || !clean_complete) {
                const struct cpumask *aff;
                struct irq_data *idata;
                int cpu_curr;

                /* in case we got here because of !clean_complete */
                done = budget;

                INC_PERF_COUNTER(priv->pstats.napi_quota);

                cpu_curr = smp_processor_id();
                idata = irq_desc_get_irq_data(cq->irq_desc);
                aff = irq_data_get_affinity_mask(idata);

                if (likely(cpumask_test_cpu(cpu_curr, aff)))
                        return budget;

                /* Current cpu is not according to smp_irq_affinity -
                 * probably affinity changed. Need to stop this NAPI
                 * poll, and restart it on the right CPU.
                 * Try to avoid returning a too small value (like 0),
                 * to not fool net_rx_action() and its netdev_budget
                 */
                if (done)
                        done--;
        }
        /* Done for now */
        if (likely(napi_complete_done(napi, done)))
                mlx4_en_arm_cq(priv, cq);
        return done;
}

void mlx4_en_calc_rx_buf(struct net_device *dev)
{
        struct mlx4_en_priv *priv = netdev_priv(dev);
        int eff_mtu = MLX4_EN_EFF_MTU(dev->mtu);
        int i = 0;

        /* bpf requires buffers to be set up as 1 packet per page.
         * This only works when num_frags == 1.
         */
        if (priv->tx_ring_num[TX_XDP]) {
                priv->frag_info[0].frag_size = eff_mtu;
                /* This will gain efficient xdp frame recycling at the
                 * expense of more costly truesize accounting
                 */
                priv->frag_info[0].frag_stride = PAGE_SIZE;
                priv->dma_dir = PCI_DMA_BIDIRECTIONAL;
                priv->rx_headroom = XDP_PACKET_HEADROOM;
                i = 1;
        } else {
                int frag_size_max = 2048, buf_size = 0;

                /* should not happen, right ? */
                if (eff_mtu > PAGE_SIZE + (MLX4_EN_MAX_RX_FRAGS - 1) * 2048)
                        frag_size_max = PAGE_SIZE;

                while (buf_size < eff_mtu) {
                        int frag_stride, frag_size = eff_mtu - buf_size;
                        int pad, nb;

                        if (i < MLX4_EN_MAX_RX_FRAGS - 1)
                                frag_size = min(frag_size, frag_size_max);

                        priv->frag_info[i].frag_size = frag_size;
                        frag_stride = ALIGN(frag_size, SMP_CACHE_BYTES);
                        /* We can only pack 2 1536-bytes frames in on 4K page
                         * Therefore, each frame would consume more bytes (truesize)
                         */
                        nb = PAGE_SIZE / frag_stride;
                        pad = (PAGE_SIZE - nb * frag_stride) / nb;
                        pad &= ~(SMP_CACHE_BYTES - 1);
                        priv->frag_info[i].frag_stride = frag_stride + pad;

                        buf_size += frag_size;
                        i++;
                }
                priv->dma_dir = PCI_DMA_FROMDEVICE;
                priv->rx_headroom = 0;
        }

        priv->num_frags = i;
        priv->rx_skb_size = eff_mtu;
        priv->log_rx_info = ROUNDUP_LOG2(i * sizeof(struct mlx4_en_rx_alloc));

        en_dbg(DRV, priv, "Rx buffer scatter-list (effective-mtu:%d num_frags:%d):\n",
               eff_mtu, priv->num_frags);
        for (i = 0; i < priv->num_frags; i++) {
                en_dbg(DRV,
                       priv,
                       "  frag:%d - size:%d stride:%d\n",
                       i,
                       priv->frag_info[i].frag_size,
                       priv->frag_info[i].frag_stride);
        }
}

/* RSS related functions */

static int mlx4_en_config_rss_qp(struct mlx4_en_priv *priv, int qpn,
                                 struct mlx4_en_rx_ring *ring,
                                 enum mlx4_qp_state *state,
                                 struct mlx4_qp *qp)
{
        struct mlx4_en_dev *mdev = priv->mdev;
        struct mlx4_qp_context *context;
        int err = 0;

        context = kmalloc(sizeof(*context), GFP_KERNEL);
        if (!context)
                return -ENOMEM;

        err = mlx4_qp_alloc(mdev->dev, qpn, qp, GFP_KERNEL);
        if (err) {
                en_err(priv, "Failed to allocate qp #%x\n", qpn);
                goto out;
        }
        qp->event = mlx4_en_sqp_event;

        memset(context, 0, sizeof *context);
        mlx4_en_fill_qp_context(priv, ring->actual_size, ring->stride, 0, 0,
                                qpn, ring->cqn, -1, context);
        context->db_rec_addr = cpu_to_be64(ring->wqres.db.dma);

        /* Cancel FCS removal if FW allows */
        if (mdev->dev->caps.flags & MLX4_DEV_CAP_FLAG_FCS_KEEP) {
                context->param3 |= cpu_to_be32(1 << 29);
                if (priv->dev->features & NETIF_F_RXFCS)
                        ring->fcs_del = 0;
                else
                        ring->fcs_del = ETH_FCS_LEN;
        } else
                ring->fcs_del = 0;

        err = mlx4_qp_to_ready(mdev->dev, &ring->wqres.mtt, context, qp, state);
        if (err) {
                mlx4_qp_remove(mdev->dev, qp);
                mlx4_qp_free(mdev->dev, qp);
        }
        mlx4_en_update_rx_prod_db(ring);
out:
        kfree(context);
        return err;
}

int mlx4_en_create_drop_qp(struct mlx4_en_priv *priv)
{
        int err;
        u32 qpn;

        err = mlx4_qp_reserve_range(priv->mdev->dev, 1, 1, &qpn,
                                    MLX4_RESERVE_A0_QP);
        if (err) {
                en_err(priv, "Failed reserving drop qpn\n");
                return err;
        }
        err = mlx4_qp_alloc(priv->mdev->dev, qpn, &priv->drop_qp, GFP_KERNEL);
        if (err) {
                en_err(priv, "Failed allocating drop qp\n");
                mlx4_qp_release_range(priv->mdev->dev, qpn, 1);
                return err;
        }

        return 0;
}

void mlx4_en_destroy_drop_qp(struct mlx4_en_priv *priv)
{
        u32 qpn;

        qpn = priv->drop_qp.qpn;
        mlx4_qp_remove(priv->mdev->dev, &priv->drop_qp);
        mlx4_qp_free(priv->mdev->dev, &priv->drop_qp);
        mlx4_qp_release_range(priv->mdev->dev, qpn, 1);
}

/* Allocate rx qp's and configure them according to rss map */
int mlx4_en_config_rss_steer(struct mlx4_en_priv *priv)
{
        struct mlx4_en_dev *mdev = priv->mdev;
        struct mlx4_en_rss_map *rss_map = &priv->rss_map;
        struct mlx4_qp_context context;
        struct mlx4_rss_context *rss_context;
        int rss_rings;
        void *ptr;
        u8 rss_mask = (MLX4_RSS_IPV4 | MLX4_RSS_TCP_IPV4 | MLX4_RSS_IPV6 |
                        MLX4_RSS_TCP_IPV6);
        int i, qpn;
        int err = 0;
        int good_qps = 0;
        u8 flags;

        en_dbg(DRV, priv, "Configuring rss steering\n");

        flags = priv->rx_ring_num == 1 ? MLX4_RESERVE_A0_QP : 0;
        err = mlx4_qp_reserve_range(mdev->dev, priv->rx_ring_num,
                                    priv->rx_ring_num,
                                    &rss_map->base_qpn, flags);
        if (err) {
                en_err(priv, "Failed reserving %d qps\n", priv->rx_ring_num);
                return err;
        }

        for (i = 0; i < priv->rx_ring_num; i++) {
                qpn = rss_map->base_qpn + i;
                err = mlx4_en_config_rss_qp(priv, qpn, priv->rx_ring[i],
                                            &rss_map->state[i],
                                            &rss_map->qps[i]);
                if (err)
                        goto rss_err;

                ++good_qps;
        }

        if (priv->rx_ring_num == 1) {
                rss_map->indir_qp = &rss_map->qps[0];
                priv->base_qpn = rss_map->indir_qp->qpn;
                en_info(priv, "Optimized Non-RSS steering\n");
                return 0;
        }

        rss_map->indir_qp = kzalloc(sizeof(*rss_map->indir_qp), GFP_KERNEL);
        if (!rss_map->indir_qp) {
                err = -ENOMEM;
                goto rss_err;
        }

        /* Configure RSS indirection qp */
        err = mlx4_qp_alloc(mdev->dev, priv->base_qpn, rss_map->indir_qp,
                            GFP_KERNEL);
        if (err) {
                en_err(priv, "Failed to allocate RSS indirection QP\n");
                goto rss_err;
        }

        rss_map->indir_qp->event = mlx4_en_sqp_event;
        mlx4_en_fill_qp_context(priv, 0, 0, 0, 1, priv->base_qpn,
                                priv->rx_ring[0]->cqn, -1, &context);

        if (!priv->prof->rss_rings || priv->prof->rss_rings > priv->rx_ring_num)
                rss_rings = priv->rx_ring_num;
        else
                rss_rings = priv->prof->rss_rings;

        ptr = ((void *) &context) + offsetof(struct mlx4_qp_context, pri_path)
                                        + MLX4_RSS_OFFSET_IN_QPC_PRI_PATH;
        rss_context = ptr;
        rss_context->base_qpn = cpu_to_be32(ilog2(rss_rings) << 24 |
                                            (rss_map->base_qpn));
        rss_context->default_qpn = cpu_to_be32(rss_map->base_qpn);
        if (priv->mdev->profile.udp_rss) {
                rss_mask |=  MLX4_RSS_UDP_IPV4 | MLX4_RSS_UDP_IPV6;
                rss_context->base_qpn_udp = rss_context->default_qpn;
        }

        if (mdev->dev->caps.tunnel_offload_mode == MLX4_TUNNEL_OFFLOAD_MODE_VXLAN) {
                en_info(priv, "Setting RSS context tunnel type to RSS on inner headers\n");
                rss_mask |= MLX4_RSS_BY_INNER_HEADERS;
        }

        rss_context->flags = rss_mask;
        rss_context->hash_fn = MLX4_RSS_HASH_TOP;
        if (priv->rss_hash_fn == ETH_RSS_HASH_XOR) {
                rss_context->hash_fn = MLX4_RSS_HASH_XOR;
        } else if (priv->rss_hash_fn == ETH_RSS_HASH_TOP) {
                rss_context->hash_fn = MLX4_RSS_HASH_TOP;
                memcpy(rss_context->rss_key, priv->rss_key,
                       MLX4_EN_RSS_KEY_SIZE);
        } else {
                en_err(priv, "Unknown RSS hash function requested\n");
                err = -EINVAL;
                goto indir_err;
        }

        err = mlx4_qp_to_ready(mdev->dev, &priv->res.mtt, &context,
                               rss_map->indir_qp, &rss_map->indir_state);
        if (err)
                goto indir_err;

        return 0;

indir_err:
        mlx4_qp_modify(mdev->dev, NULL, rss_map->indir_state,
                       MLX4_QP_STATE_RST, NULL, 0, 0, rss_map->indir_qp);
        mlx4_qp_remove(mdev->dev, rss_map->indir_qp);
        mlx4_qp_free(mdev->dev, rss_map->indir_qp);
        kfree(rss_map->indir_qp);
        rss_map->indir_qp = NULL;
rss_err:
        for (i = 0; i < good_qps; i++) {
                mlx4_qp_modify(mdev->dev, NULL, rss_map->state[i],
                               MLX4_QP_STATE_RST, NULL, 0, 0, &rss_map->qps[i]);
                mlx4_qp_remove(mdev->dev, &rss_map->qps[i]);
                mlx4_qp_free(mdev->dev, &rss_map->qps[i]);
        }
        mlx4_qp_release_range(mdev->dev, rss_map->base_qpn, priv->rx_ring_num);
        return err;
}

void mlx4_en_release_rss_steer(struct mlx4_en_priv *priv)
{
        struct mlx4_en_dev *mdev = priv->mdev;
        struct mlx4_en_rss_map *rss_map = &priv->rss_map;
        int i;

        if (priv->rx_ring_num > 1) {
                mlx4_qp_modify(mdev->dev, NULL, rss_map->indir_state,
                               MLX4_QP_STATE_RST, NULL, 0, 0,
                               rss_map->indir_qp);
                mlx4_qp_remove(mdev->dev, rss_map->indir_qp);
                mlx4_qp_free(mdev->dev, rss_map->indir_qp);
                kfree(rss_map->indir_qp);
                rss_map->indir_qp = NULL;
        }

        for (i = 0; i < priv->rx_ring_num; i++) {
                mlx4_qp_modify(mdev->dev, NULL, rss_map->state[i],
                               MLX4_QP_STATE_RST, NULL, 0, 0, &rss_map->qps[i]);
                mlx4_qp_remove(mdev->dev, &rss_map->qps[i]);
                mlx4_qp_free(mdev->dev, &rss_map->qps[i]);
        }
        mlx4_qp_release_range(mdev->dev, rss_map->base_qpn, priv->rx_ring_num);
}