// SPDX-License-Identifier: GPL-2.0-only
/****************************************************************************
 * Driver for Solarflare network controllers and boards
 * Copyright 2018 Solarflare Communications Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation, incorporated herein by reference.
 */

#include "net_driver.h"
#include <linux/module.h>
#include <linux/iommu.h>
#include "efx.h"
#include "nic.h"
#include "rx_common.h"

/* This is the percentage fill level below which new RX descriptors
 * will be added to the RX descriptor ring.
 */
static unsigned int rx_refill_threshold;
module_param(rx_refill_threshold, uint, 0444);
MODULE_PARM_DESC(rx_refill_threshold,
                 "RX descriptor ring refill threshold (%)");

/* Number of RX buffers to recycle pages for.  When creating the RX page recycle
 * ring, this number is divided by the number of buffers per page to calculate
 * the number of pages to store in the RX page recycle ring.
 */
#define EFX_RECYCLE_RING_SIZE_IOMMU 4096
#define EFX_RECYCLE_RING_SIZE_NOIOMMU (2 * EFX_RX_PREFERRED_BATCH)

/* RX maximum head room required.
 *
 * This must be at least 1 to prevent overflow, plus one packet-worth
 * to allow pipelined receives.
 */
#define EFX_RXD_HEAD_ROOM (1 + EFX_RX_MAX_FRAGS)

/* Check the RX page recycle ring for a page that can be reused. */
static struct page *efx_reuse_page(struct efx_rx_queue *rx_queue)
{
        struct efx_nic *efx = rx_queue->efx;
        struct efx_rx_page_state *state;
        unsigned int index;
        struct page *page;

        index = rx_queue->page_remove & rx_queue->page_ptr_mask;
        page = rx_queue->page_ring[index];
        if (page == NULL)
                return NULL;

        rx_queue->page_ring[index] = NULL;
        /* page_remove cannot exceed page_add. */
        if (rx_queue->page_remove != rx_queue->page_add)
                ++rx_queue->page_remove;

        /* If page_count is 1 then we hold the only reference to this page. */
        if (page_count(page) == 1) {
                ++rx_queue->page_recycle_count;
                return page;
        } else {
                state = page_address(page);
                dma_unmap_page(&efx->pci_dev->dev, state->dma_addr,
                               PAGE_SIZE << efx->rx_buffer_order,
                               DMA_FROM_DEVICE);
                put_page(page);
                ++rx_queue->page_recycle_failed;
        }

        return NULL;
}

/* Attempt to recycle the page if there is an RX recycle ring; the page can
 * only be added if this is the final RX buffer, to prevent pages being used in
 * the descriptor ring and appearing in the recycle ring simultaneously.
 */
static void efx_recycle_rx_page(struct efx_channel *channel,
                                struct efx_rx_buffer *rx_buf)
{
        struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
        struct efx_nic *efx = rx_queue->efx;
        struct page *page = rx_buf->page;
        unsigned int index;

        /* Only recycle the page after processing the final buffer. */
        if (!(rx_buf->flags & EFX_RX_BUF_LAST_IN_PAGE))
                return;

        index = rx_queue->page_add & rx_queue->page_ptr_mask;
        if (rx_queue->page_ring[index] == NULL) {
                unsigned int read_index = rx_queue->page_remove &
                        rx_queue->page_ptr_mask;

                /* The next slot in the recycle ring is available, but
                 * increment page_remove if the read pointer currently
                 * points here.
                 */
                if (read_index == index)
                        ++rx_queue->page_remove;
                rx_queue->page_ring[index] = page;
                ++rx_queue->page_add;
                return;
        }
        ++rx_queue->page_recycle_full;
        efx_unmap_rx_buffer(efx, rx_buf);
        put_page(rx_buf->page);
}

/* Recycle the pages that are used by buffers that have just been received. */
void efx_recycle_rx_pages(struct efx_channel *channel,
                          struct efx_rx_buffer *rx_buf,
                          unsigned int n_frags)
{
        struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);

        do {
                efx_recycle_rx_page(channel, rx_buf);
                rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
        } while (--n_frags);
}

void efx_discard_rx_packet(struct efx_channel *channel,
                           struct efx_rx_buffer *rx_buf,
                           unsigned int n_frags)
{
        struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);

        efx_recycle_rx_pages(channel, rx_buf, n_frags);

        efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
}

static void efx_init_rx_recycle_ring(struct efx_rx_queue *rx_queue)
{
        unsigned int bufs_in_recycle_ring, page_ring_size;
        struct efx_nic *efx = rx_queue->efx;

        /* Set the RX recycle ring size */
#ifdef CONFIG_PPC64
        bufs_in_recycle_ring = EFX_RECYCLE_RING_SIZE_IOMMU;
#else
        if (iommu_present(&pci_bus_type))
                bufs_in_recycle_ring = EFX_RECYCLE_RING_SIZE_IOMMU;
        else
                bufs_in_recycle_ring = EFX_RECYCLE_RING_SIZE_NOIOMMU;
#endif /* CONFIG_PPC64 */

        page_ring_size = roundup_pow_of_two(bufs_in_recycle_ring /
                                            efx->rx_bufs_per_page);
        rx_queue->page_ring = kcalloc(page_ring_size,
                                      sizeof(*rx_queue->page_ring), GFP_KERNEL);
        rx_queue->page_ptr_mask = page_ring_size - 1;
}

static void efx_fini_rx_recycle_ring(struct efx_rx_queue *rx_queue)
{
        struct efx_nic *efx = rx_queue->efx;
        int i;

        /* Unmap and release the pages in the recycle ring. Remove the ring. */
        for (i = 0; i <= rx_queue->page_ptr_mask; i++) {
                struct page *page = rx_queue->page_ring[i];
                struct efx_rx_page_state *state;

                if (page == NULL)
                        continue;

                state = page_address(page);
                dma_unmap_page(&efx->pci_dev->dev, state->dma_addr,
                               PAGE_SIZE << efx->rx_buffer_order,
                               DMA_FROM_DEVICE);
                put_page(page);
        }
        kfree(rx_queue->page_ring);
        rx_queue->page_ring = NULL;
}

static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
                               struct efx_rx_buffer *rx_buf)
{
        /* Release the page reference we hold for the buffer. */
        if (rx_buf->page)
                put_page(rx_buf->page);

        /* If this is the last buffer in a page, unmap and free it. */
        if (rx_buf->flags & EFX_RX_BUF_LAST_IN_PAGE) {
                efx_unmap_rx_buffer(rx_queue->efx, rx_buf);
                efx_free_rx_buffers(rx_queue, rx_buf, 1);
        }
        rx_buf->page = NULL;
}

int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
{
        struct efx_nic *efx = rx_queue->efx;
        unsigned int entries;
        int rc;

        /* Create the smallest power-of-two aligned ring */
        entries = max(roundup_pow_of_two(efx->rxq_entries), EFX_MIN_DMAQ_SIZE);
        EFX_WARN_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE);
        rx_queue->ptr_mask = entries - 1;

        netif_dbg(efx, probe, efx->net_dev,
                  "creating RX queue %d size %#x mask %#x\n",
                  efx_rx_queue_index(rx_queue), efx->rxq_entries,
                  rx_queue->ptr_mask);

        /* Allocate RX buffers */
        rx_queue->buffer = kcalloc(entries, sizeof(*rx_queue->buffer),
                                   GFP_KERNEL);
        if (!rx_queue->buffer)
                return -ENOMEM;

        rc = efx_nic_probe_rx(rx_queue);
        if (rc) {
                kfree(rx_queue->buffer);
                rx_queue->buffer = NULL;
        }

        return rc;
}

void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
{
        unsigned int max_fill, trigger, max_trigger;
        struct efx_nic *efx = rx_queue->efx;
        int rc = 0;

        netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
                  "initialising RX queue %d\n", efx_rx_queue_index(rx_queue));

        /* Initialise ptr fields */
        rx_queue->added_count = 0;
        rx_queue->notified_count = 0;
        rx_queue->removed_count = 0;
        rx_queue->min_fill = -1U;
        efx_init_rx_recycle_ring(rx_queue);

        rx_queue->page_remove = 0;
        rx_queue->page_add = rx_queue->page_ptr_mask + 1;
        rx_queue->page_recycle_count = 0;
        rx_queue->page_recycle_failed = 0;
        rx_queue->page_recycle_full = 0;

        /* Initialise limit fields */
        max_fill = efx->rxq_entries - EFX_RXD_HEAD_ROOM;
        max_trigger =
                max_fill - efx->rx_pages_per_batch * efx->rx_bufs_per_page;
        if (rx_refill_threshold != 0) {
                trigger = max_fill * min(rx_refill_threshold, 100U) / 100U;
                if (trigger > max_trigger)
                        trigger = max_trigger;
        } else {
                trigger = max_trigger;
        }

        rx_queue->max_fill = max_fill;
        rx_queue->fast_fill_trigger = trigger;
        rx_queue->refill_enabled = true;

        /* Initialise XDP queue information */
        rc = xdp_rxq_info_reg(&rx_queue->xdp_rxq_info, efx->net_dev,
                              rx_queue->core_index, 0);

        if (rc) {
                netif_err(efx, rx_err, efx->net_dev,
                          "Failure to initialise XDP queue information rc=%d\n",
                          rc);
                efx->xdp_rxq_info_failed = true;
        } else {
                rx_queue->xdp_rxq_info_valid = true;
        }

        /* Set up RX descriptor ring */
        efx_nic_init_rx(rx_queue);
}

void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
{
        struct efx_rx_buffer *rx_buf;
        int i;

        netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
                  "shutting down RX queue %d\n", efx_rx_queue_index(rx_queue));

        del_timer_sync(&rx_queue->slow_fill);

        /* Release RX buffers from the current read ptr to the write ptr */
        if (rx_queue->buffer) {
                for (i = rx_queue->removed_count; i < rx_queue->added_count;
                     i++) {
                        unsigned int index = i & rx_queue->ptr_mask;

                        rx_buf = efx_rx_buffer(rx_queue, index);
                        efx_fini_rx_buffer(rx_queue, rx_buf);
                }
        }

        efx_fini_rx_recycle_ring(rx_queue);

        if (rx_queue->xdp_rxq_info_valid)
                xdp_rxq_info_unreg(&rx_queue->xdp_rxq_info);

        rx_queue->xdp_rxq_info_valid = false;
}

void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)
{
        netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
                  "destroying RX queue %d\n", efx_rx_queue_index(rx_queue));

        efx_nic_remove_rx(rx_queue);

        kfree(rx_queue->buffer);
        rx_queue->buffer = NULL;
}

/* Unmap a DMA-mapped page.  This function is only called for the final RX
 * buffer in a page.
 */
void efx_unmap_rx_buffer(struct efx_nic *efx,
                         struct efx_rx_buffer *rx_buf)
{
        struct page *page = rx_buf->page;

        if (page) {
                struct efx_rx_page_state *state = page_address(page);

                dma_unmap_page(&efx->pci_dev->dev,
                               state->dma_addr,
                               PAGE_SIZE << efx->rx_buffer_order,
                               DMA_FROM_DEVICE);
        }
}

void efx_free_rx_buffers(struct efx_rx_queue *rx_queue,
                         struct efx_rx_buffer *rx_buf,
                         unsigned int num_bufs)
{
        do {
                if (rx_buf->page) {
                        put_page(rx_buf->page);
                        rx_buf->page = NULL;
                }
                rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
        } while (--num_bufs);
}

void efx_rx_slow_fill(struct timer_list *t)
{
        struct efx_rx_queue *rx_queue = from_timer(rx_queue, t, slow_fill);

        /* Post an event to cause NAPI to run and refill the queue */
        efx_nic_generate_fill_event(rx_queue);
        ++rx_queue->slow_fill_count;
}

void efx_schedule_slow_fill(struct efx_rx_queue *rx_queue)
{
        mod_timer(&rx_queue->slow_fill, jiffies + msecs_to_jiffies(10));
}

/* efx_init_rx_buffers - create EFX_RX_BATCH page-based RX buffers
 *
 * @rx_queue:           Efx RX queue
 *
 * This allocates a batch of pages, maps them for DMA, and populates
 * struct efx_rx_buffers for each one. Return a negative error code or
 * 0 on success. If a single page can be used for multiple buffers,
 * then the page will either be inserted fully, or not at all.
 */
static int efx_init_rx_buffers(struct efx_rx_queue *rx_queue, bool atomic)
{
        unsigned int page_offset, index, count;
        struct efx_nic *efx = rx_queue->efx;
        struct efx_rx_page_state *state;
        struct efx_rx_buffer *rx_buf;
        dma_addr_t dma_addr;
        struct page *page;

        count = 0;
        do {
                page = efx_reuse_page(rx_queue);
                if (page == NULL) {
                        page = alloc_pages(__GFP_COMP |
                                           (atomic ? GFP_ATOMIC : GFP_KERNEL),
                                           efx->rx_buffer_order);
                        if (unlikely(page == NULL))
                                return -ENOMEM;
                        dma_addr =
                                dma_map_page(&efx->pci_dev->dev, page, 0,
                                             PAGE_SIZE << efx->rx_buffer_order,
                                             DMA_FROM_DEVICE);
                        if (unlikely(dma_mapping_error(&efx->pci_dev->dev,
                                                       dma_addr))) {
                                __free_pages(page, efx->rx_buffer_order);
                                return -EIO;
                        }
                        state = page_address(page);
                        state->dma_addr = dma_addr;
                } else {
                        state = page_address(page);
                        dma_addr = state->dma_addr;
                }

                dma_addr += sizeof(struct efx_rx_page_state);
                page_offset = sizeof(struct efx_rx_page_state);

                do {
                        index = rx_queue->added_count & rx_queue->ptr_mask;
                        rx_buf = efx_rx_buffer(rx_queue, index);
                        rx_buf->dma_addr = dma_addr + efx->rx_ip_align +
                                           EFX_XDP_HEADROOM;
                        rx_buf->page = page;
                        rx_buf->page_offset = page_offset + efx->rx_ip_align +
                                              EFX_XDP_HEADROOM;
                        rx_buf->len = efx->rx_dma_len;
                        rx_buf->flags = 0;
                        ++rx_queue->added_count;
                        get_page(page);
                        dma_addr += efx->rx_page_buf_step;
                        page_offset += efx->rx_page_buf_step;
                } while (page_offset + efx->rx_page_buf_step <= PAGE_SIZE);

                rx_buf->flags = EFX_RX_BUF_LAST_IN_PAGE;
        } while (++count < efx->rx_pages_per_batch);

        return 0;
}

void efx_rx_config_page_split(struct efx_nic *efx)
{
        efx->rx_page_buf_step = ALIGN(efx->rx_dma_len + efx->rx_ip_align +
                                      EFX_XDP_HEADROOM + EFX_XDP_TAILROOM,
                                      EFX_RX_BUF_ALIGNMENT);
        efx->rx_bufs_per_page = efx->rx_buffer_order ? 1 :
                ((PAGE_SIZE - sizeof(struct efx_rx_page_state)) /
                efx->rx_page_buf_step);
        efx->rx_buffer_truesize = (PAGE_SIZE << efx->rx_buffer_order) /
                efx->rx_bufs_per_page;
        efx->rx_pages_per_batch = DIV_ROUND_UP(EFX_RX_PREFERRED_BATCH,
                                               efx->rx_bufs_per_page);
}

/* efx_fast_push_rx_descriptors - push new RX descriptors quickly
 * @rx_queue:           RX descriptor queue
 *
 * This will aim to fill the RX descriptor queue up to
 * @rx_queue->@max_fill. If there is insufficient atomic
 * memory to do so, a slow fill will be scheduled.
 *
 * The caller must provide serialisation (none is used here). In practise,
 * this means this function must run from the NAPI handler, or be called
 * when NAPI is disabled.
 */
void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue, bool atomic)
{
        struct efx_nic *efx = rx_queue->efx;
        unsigned int fill_level, batch_size;
        int space, rc = 0;

        if (!rx_queue->refill_enabled)
                return;

        /* Calculate current fill level, and exit if we don't need to fill */
        fill_level = (rx_queue->added_count - rx_queue->removed_count);
        EFX_WARN_ON_ONCE_PARANOID(fill_level > rx_queue->efx->rxq_entries);
        if (fill_level >= rx_queue->fast_fill_trigger)
                goto out;

        /* Record minimum fill level */
        if (unlikely(fill_level < rx_queue->min_fill)) {
                if (fill_level)
                        rx_queue->min_fill = fill_level;
        }

        batch_size = efx->rx_pages_per_batch * efx->rx_bufs_per_page;
        space = rx_queue->max_fill - fill_level;
        EFX_WARN_ON_ONCE_PARANOID(space < batch_size);

        netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
                   "RX queue %d fast-filling descriptor ring from"
                   " level %d to level %d\n",
                   efx_rx_queue_index(rx_queue), fill_level,
                   rx_queue->max_fill);

        do {
                rc = efx_init_rx_buffers(rx_queue, atomic);
                if (unlikely(rc)) {
                        /* Ensure that we don't leave the rx queue empty */
                        efx_schedule_slow_fill(rx_queue);
                        goto out;
                }
        } while ((space -= batch_size) >= batch_size);

        netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
                   "RX queue %d fast-filled descriptor ring "
                   "to level %d\n", efx_rx_queue_index(rx_queue),
                   rx_queue->added_count - rx_queue->removed_count);

 out:
        if (rx_queue->notified_count != rx_queue->added_count)
                efx_nic_notify_rx_desc(rx_queue);
}

/* Pass a received packet up through GRO.  GRO can handle pages
 * regardless of checksum state and skbs with a good checksum.
 */
void
efx_rx_packet_gro(struct efx_channel *channel, struct efx_rx_buffer *rx_buf,
                  unsigned int n_frags, u8 *eh, __wsum csum)
{
        struct napi_struct *napi = &channel->napi_str;
        struct efx_nic *efx = channel->efx;
        struct sk_buff *skb;

        skb = napi_get_frags(napi);
        if (unlikely(!skb)) {
                struct efx_rx_queue *rx_queue;

                rx_queue = efx_channel_get_rx_queue(channel);
                efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
                return;
        }

        if (efx->net_dev->features & NETIF_F_RXHASH &&
            efx_rx_buf_hash_valid(efx, eh))
                skb_set_hash(skb, efx_rx_buf_hash(efx, eh),
                             PKT_HASH_TYPE_L3);
        if (csum) {
                skb->csum = csum;
                skb->ip_summed = CHECKSUM_COMPLETE;
        } else {
                skb->ip_summed = ((rx_buf->flags & EFX_RX_PKT_CSUMMED) ?
                                  CHECKSUM_UNNECESSARY : CHECKSUM_NONE);
        }
        skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);

        for (;;) {
                skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags,
                                   rx_buf->page, rx_buf->page_offset,
                                   rx_buf->len);
                rx_buf->page = NULL;
                skb->len += rx_buf->len;
                if (skb_shinfo(skb)->nr_frags == n_frags)
                        break;

                rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
        }

        skb->data_len = skb->len;
        skb->truesize += n_frags * efx->rx_buffer_truesize;

        skb_record_rx_queue(skb, channel->rx_queue.core_index);

        napi_gro_frags(napi);
}

/* RSS contexts.  We're using linked lists and crappy O(n) algorithms, because
 * (a) this is an infrequent control-plane operation and (b) n is small (max 64)
 */
struct efx_rss_context *efx_alloc_rss_context_entry(struct efx_nic *efx)
{
        struct list_head *head = &efx->rss_context.list;
        struct efx_rss_context *ctx, *new;
        u32 id = 1; /* Don't use zero, that refers to the master RSS context */

        WARN_ON(!mutex_is_locked(&efx->rss_lock));

        /* Search for first gap in the numbering */
        list_for_each_entry(ctx, head, list) {
                if (ctx->user_id != id)
                        break;
                id++;
                /* Check for wrap.  If this happens, we have nearly 2^32
                 * allocated RSS contexts, which seems unlikely.
                 */
                if (WARN_ON_ONCE(!id))
                        return NULL;
        }

        /* Create the new entry */
        new = kmalloc(sizeof(*new), GFP_KERNEL);
        if (!new)
                return NULL;
        new->context_id = EFX_MCDI_RSS_CONTEXT_INVALID;
        new->rx_hash_udp_4tuple = false;

        /* Insert the new entry into the gap */
        new->user_id = id;
        list_add_tail(&new->list, &ctx->list);
        return new;
}

struct efx_rss_context *efx_find_rss_context_entry(struct efx_nic *efx, u32 id)
{
        struct list_head *head = &efx->rss_context.list;
        struct efx_rss_context *ctx;

        WARN_ON(!mutex_is_locked(&efx->rss_lock));

        list_for_each_entry(ctx, head, list)
                if (ctx->user_id == id)
                        return ctx;
        return NULL;
}

void efx_free_rss_context_entry(struct efx_rss_context *ctx)
{
        list_del(&ctx->list);
        kfree(ctx);
}

void efx_set_default_rx_indir_table(struct efx_nic *efx,
                                    struct efx_rss_context *ctx)
{
        size_t i;

        for (i = 0; i < ARRAY_SIZE(ctx->rx_indir_table); i++)
                ctx->rx_indir_table[i] =
                        ethtool_rxfh_indir_default(i, efx->rss_spread);
}

/**
 * efx_filter_is_mc_recipient - test whether spec is a multicast recipient
 * @spec: Specification to test
 *
 * Return: %true if the specification is a non-drop RX filter that
 * matches a local MAC address I/G bit value of 1 or matches a local
 * IPv4 or IPv6 address value in the respective multicast address
 * range.  Otherwise %false.
 */
bool efx_filter_is_mc_recipient(const struct efx_filter_spec *spec)
{
        if (!(spec->flags & EFX_FILTER_FLAG_RX) ||
            spec->dmaq_id == EFX_FILTER_RX_DMAQ_ID_DROP)
                return false;

        if (spec->match_flags &
            (EFX_FILTER_MATCH_LOC_MAC | EFX_FILTER_MATCH_LOC_MAC_IG) &&
            is_multicast_ether_addr(spec->loc_mac))
                return true;

        if ((spec->match_flags &
             (EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_LOC_HOST)) ==
            (EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_LOC_HOST)) {
                if (spec->ether_type == htons(ETH_P_IP) &&
                    ipv4_is_multicast(spec->loc_host[0]))
                        return true;
                if (spec->ether_type == htons(ETH_P_IPV6) &&
                    ((const u8 *)spec->loc_host)[0] == 0xff)
                        return true;
        }

        return false;
}

bool efx_filter_spec_equal(const struct efx_filter_spec *left,
                           const struct efx_filter_spec *right)
{
        if ((left->match_flags ^ right->match_flags) |
            ((left->flags ^ right->flags) &
             (EFX_FILTER_FLAG_RX | EFX_FILTER_FLAG_TX)))
                return false;

        return memcmp(&left->outer_vid, &right->outer_vid,
                      sizeof(struct efx_filter_spec) -
                      offsetof(struct efx_filter_spec, outer_vid)) == 0;
}

u32 efx_filter_spec_hash(const struct efx_filter_spec *spec)
{
        BUILD_BUG_ON(offsetof(struct efx_filter_spec, outer_vid) & 3);
        return jhash2((const u32 *)&spec->outer_vid,
                      (sizeof(struct efx_filter_spec) -
                       offsetof(struct efx_filter_spec, outer_vid)) / 4,
                      0);
}

#ifdef CONFIG_RFS_ACCEL
bool efx_rps_check_rule(struct efx_arfs_rule *rule, unsigned int filter_idx,
                        bool *force)
{
        if (rule->filter_id == EFX_ARFS_FILTER_ID_PENDING) {
                /* ARFS is currently updating this entry, leave it */
                return false;
        }
        if (rule->filter_id == EFX_ARFS_FILTER_ID_ERROR) {
                /* ARFS tried and failed to update this, so it's probably out
                 * of date.  Remove the filter and the ARFS rule entry.
                 */
                rule->filter_id = EFX_ARFS_FILTER_ID_REMOVING;
                *force = true;
                return true;
        } else if (WARN_ON(rule->filter_id != filter_idx)) { /* can't happen */
                /* ARFS has moved on, so old filter is not needed.  Since we did
                 * not mark the rule with EFX_ARFS_FILTER_ID_REMOVING, it will
                 * not be removed by efx_rps_hash_del() subsequently.
                 */
                *force = true;
                return true;
        }
        /* Remove it iff ARFS wants to. */
        return true;
}

static
struct hlist_head *efx_rps_hash_bucket(struct efx_nic *efx,
                                       const struct efx_filter_spec *spec)
{
        u32 hash = efx_filter_spec_hash(spec);

        lockdep_assert_held(&efx->rps_hash_lock);
        if (!efx->rps_hash_table)
                return NULL;
        return &efx->rps_hash_table[hash % EFX_ARFS_HASH_TABLE_SIZE];
}

struct efx_arfs_rule *efx_rps_hash_find(struct efx_nic *efx,
                                        const struct efx_filter_spec *spec)
{
        struct efx_arfs_rule *rule;
        struct hlist_head *head;
        struct hlist_node *node;

        head = efx_rps_hash_bucket(efx, spec);
        if (!head)
                return NULL;
        hlist_for_each(node, head) {
                rule = container_of(node, struct efx_arfs_rule, node);
                if (efx_filter_spec_equal(spec, &rule->spec))
                        return rule;
        }
        return NULL;
}

struct efx_arfs_rule *efx_rps_hash_add(struct efx_nic *efx,
                                       const struct efx_filter_spec *spec,
                                       bool *new)
{
        struct efx_arfs_rule *rule;
        struct hlist_head *head;
        struct hlist_node *node;

        head = efx_rps_hash_bucket(efx, spec);
        if (!head)
                return NULL;
        hlist_for_each(node, head) {
                rule = container_of(node, struct efx_arfs_rule, node);
                if (efx_filter_spec_equal(spec, &rule->spec)) {
                        *new = false;
                        return rule;
                }
        }
        rule = kmalloc(sizeof(*rule), GFP_ATOMIC);
        *new = true;
        if (rule) {
                memcpy(&rule->spec, spec, sizeof(rule->spec));
                hlist_add_head(&rule->node, head);
        }
        return rule;
}

void efx_rps_hash_del(struct efx_nic *efx, const struct efx_filter_spec *spec)
{
        struct efx_arfs_rule *rule;
        struct hlist_head *head;
        struct hlist_node *node;

        head = efx_rps_hash_bucket(efx, spec);
        if (WARN_ON(!head))
                return;
        hlist_for_each(node, head) {
                rule = container_of(node, struct efx_arfs_rule, node);
                if (efx_filter_spec_equal(spec, &rule->spec)) {
                        /* Someone already reused the entry.  We know that if
                         * this check doesn't fire (i.e. filter_id == REMOVING)
                         * then the REMOVING mark was put there by our caller,
                         * because caller is holding a lock on filter table and
                         * only holders of that lock set REMOVING.
                         */
                        if (rule->filter_id != EFX_ARFS_FILTER_ID_REMOVING)
                                return;
                        hlist_del(node);
                        kfree(rule);
                        return;
                }
        }
        /* We didn't find it. */
        WARN_ON(1);
}
#endif

int efx_probe_filters(struct efx_nic *efx)
{
        int rc;

        mutex_lock(&efx->mac_lock);
        down_write(&efx->filter_sem);
        rc = efx->type->filter_table_probe(efx);
        if (rc)
                goto out_unlock;

#ifdef CONFIG_RFS_ACCEL
        if (efx->type->offload_features & NETIF_F_NTUPLE) {
                struct efx_channel *channel;
                int i, success = 1;

                efx_for_each_channel(channel, efx) {
                        channel->rps_flow_id =
                                kcalloc(efx->type->max_rx_ip_filters,
                                        sizeof(*channel->rps_flow_id),
                                        GFP_KERNEL);
                        if (!channel->rps_flow_id)
                                success = 0;
                        else
                                for (i = 0;
                                     i < efx->type->max_rx_ip_filters;
                                     ++i)
                                        channel->rps_flow_id[i] =
                                                RPS_FLOW_ID_INVALID;
                        channel->rfs_expire_index = 0;
                        channel->rfs_filter_count = 0;
                }

                if (!success) {
                        efx_for_each_channel(channel, efx)
                                kfree(channel->rps_flow_id);
                        efx->type->filter_table_remove(efx);
                        rc = -ENOMEM;
                        goto out_unlock;
                }
        }
#endif
out_unlock:
        up_write(&efx->filter_sem);
        mutex_unlock(&efx->mac_lock);
        return rc;
}

void efx_remove_filters(struct efx_nic *efx)
{
#ifdef CONFIG_RFS_ACCEL
        struct efx_channel *channel;

        efx_for_each_channel(channel, efx) {
                cancel_delayed_work_sync(&channel->filter_work);
                kfree(channel->rps_flow_id);
                channel->rps_flow_id = NULL;
        }
#endif
        down_write(&efx->filter_sem);
        efx->type->filter_table_remove(efx);
        up_write(&efx->filter_sem);
}

#ifdef CONFIG_RFS_ACCEL

static void efx_filter_rfs_work(struct work_struct *data)
{
        struct efx_async_filter_insertion *req = container_of(data, struct efx_async_filter_insertion,
                                                              work);
        struct efx_nic *efx = netdev_priv(req->net_dev);
        struct efx_channel *channel = efx_get_channel(efx, req->rxq_index);
        int slot_idx = req - efx->rps_slot;
        struct efx_arfs_rule *rule;
        u16 arfs_id = 0;
        int rc;

        rc = efx->type->filter_insert(efx, &req->spec, true);
        if (rc >= 0)
                /* Discard 'priority' part of EF10+ filter ID (mcdi_filters) */
                rc %= efx->type->max_rx_ip_filters;
        if (efx->rps_hash_table) {
                spin_lock_bh(&efx->rps_hash_lock);
                rule = efx_rps_hash_find(efx, &req->spec);
                /* The rule might have already gone, if someone else's request
                 * for the same spec was already worked and then expired before
                 * we got around to our work.  In that case we have nothing
                 * tying us to an arfs_id, meaning that as soon as the filter
                 * is considered for expiry it will be removed.
                 */
                if (rule) {
                        if (rc < 0)
                                rule->filter_id = EFX_ARFS_FILTER_ID_ERROR;
                        else
                                rule->filter_id = rc;
                        arfs_id = rule->arfs_id;
                }
                spin_unlock_bh(&efx->rps_hash_lock);
        }
        if (rc >= 0) {
                /* Remember this so we can check whether to expire the filter
                 * later.
                 */
                mutex_lock(&efx->rps_mutex);
                if (channel->rps_flow_id[rc] == RPS_FLOW_ID_INVALID)
                        channel->rfs_filter_count++;
                channel->rps_flow_id[rc] = req->flow_id;
                mutex_unlock(&efx->rps_mutex);

                if (req->spec.ether_type == htons(ETH_P_IP))
                        netif_info(efx, rx_status, efx->net_dev,
                                   "steering %s %pI4:%u:%pI4:%u to queue %u [flow %u filter %d id %u]\n",
                                   (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
                                   req->spec.rem_host, ntohs(req->spec.rem_port),
                                   req->spec.loc_host, ntohs(req->spec.loc_port),
                                   req->rxq_index, req->flow_id, rc, arfs_id);
                else
                        netif_info(efx, rx_status, efx->net_dev,
                                   "steering %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u filter %d id %u]\n",
                                   (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
                                   req->spec.rem_host, ntohs(req->spec.rem_port),
                                   req->spec.loc_host, ntohs(req->spec.loc_port),
                                   req->rxq_index, req->flow_id, rc, arfs_id);
                channel->n_rfs_succeeded++;
        } else {
                if (req->spec.ether_type == htons(ETH_P_IP))
                        netif_dbg(efx, rx_status, efx->net_dev,
                                  "failed to steer %s %pI4:%u:%pI4:%u to queue %u [flow %u rc %d id %u]\n",
                                  (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
                                  req->spec.rem_host, ntohs(req->spec.rem_port),
                                  req->spec.loc_host, ntohs(req->spec.loc_port),
                                  req->rxq_index, req->flow_id, rc, arfs_id);
                else
                        netif_dbg(efx, rx_status, efx->net_dev,
                                  "failed to steer %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u rc %d id %u]\n",
                                  (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
                                  req->spec.rem_host, ntohs(req->spec.rem_port),
                                  req->spec.loc_host, ntohs(req->spec.loc_port),
                                  req->rxq_index, req->flow_id, rc, arfs_id);
                channel->n_rfs_failed++;
                /* We're overloading the NIC's filter tables, so let's do a
                 * chunk of extra expiry work.
                 */
                __efx_filter_rfs_expire(channel, min(channel->rfs_filter_count,
                                                     100u));
        }

        /* Release references */
        clear_bit(slot_idx, &efx->rps_slot_map);
        dev_put(req->net_dev);
}

int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
                   u16 rxq_index, u32 flow_id)
{
        struct efx_nic *efx = netdev_priv(net_dev);
        struct efx_async_filter_insertion *req;
        struct efx_arfs_rule *rule;
        struct flow_keys fk;
        int slot_idx;
        bool new;
        int rc;

        /* find a free slot */
        for (slot_idx = 0; slot_idx < EFX_RPS_MAX_IN_FLIGHT; slot_idx++)
                if (!test_and_set_bit(slot_idx, &efx->rps_slot_map))
                        break;
        if (slot_idx >= EFX_RPS_MAX_IN_FLIGHT)
                return -EBUSY;

        if (flow_id == RPS_FLOW_ID_INVALID) {
                rc = -EINVAL;
                goto out_clear;
        }

        if (!skb_flow_dissect_flow_keys(skb, &fk, 0)) {
                rc = -EPROTONOSUPPORT;
                goto out_clear;
        }

        if (fk.basic.n_proto != htons(ETH_P_IP) && fk.basic.n_proto != htons(ETH_P_IPV6)) {
                rc = -EPROTONOSUPPORT;
                goto out_clear;
        }
        if (fk.control.flags & FLOW_DIS_IS_FRAGMENT) {
                rc = -EPROTONOSUPPORT;
                goto out_clear;
        }

        req = efx->rps_slot + slot_idx;
        efx_filter_init_rx(&req->spec, EFX_FILTER_PRI_HINT,
                           efx->rx_scatter ? EFX_FILTER_FLAG_RX_SCATTER : 0,
                           rxq_index);
        req->spec.match_flags =
                EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_IP_PROTO |
                EFX_FILTER_MATCH_LOC_HOST | EFX_FILTER_MATCH_LOC_PORT |
                EFX_FILTER_MATCH_REM_HOST | EFX_FILTER_MATCH_REM_PORT;
        req->spec.ether_type = fk.basic.n_proto;
        req->spec.ip_proto = fk.basic.ip_proto;

        if (fk.basic.n_proto == htons(ETH_P_IP)) {
                req->spec.rem_host[0] = fk.addrs.v4addrs.src;
                req->spec.loc_host[0] = fk.addrs.v4addrs.dst;
        } else {
                memcpy(req->spec.rem_host, &fk.addrs.v6addrs.src,
                       sizeof(struct in6_addr));

                memcpy(req->spec.loc_host, &fk.addrs.v6addrs.dst,
                       sizeof(struct in6_addr));
        }

        req->spec.rem_port = fk.ports.src;
        req->spec.loc_port = fk.ports.dst;

        if (efx->rps_hash_table) {
                /* Add it to ARFS hash table */
                spin_lock(&efx->rps_hash_lock);
                rule = efx_rps_hash_add(efx, &req->spec, &new);
                if (!rule) {
                        rc = -ENOMEM;
                        goto out_unlock;
                }
                if (new)
                        rule->arfs_id = efx->rps_next_id++ % RPS_NO_FILTER;
                rc = rule->arfs_id;
                /* Skip if existing or pending filter already does the right thing */
                if (!new && rule->rxq_index == rxq_index &&
                    rule->filter_id >= EFX_ARFS_FILTER_ID_PENDING)
                        goto out_unlock;
                rule->rxq_index = rxq_index;
                rule->filter_id = EFX_ARFS_FILTER_ID_PENDING;
                spin_unlock(&efx->rps_hash_lock);
        } else {
                /* Without an ARFS hash table, we just use arfs_id 0 for all
                 * filters.  This means if multiple flows hash to the same
                 * flow_id, all but the most recently touched will be eligible
                 * for expiry.
                 */
                rc = 0;
        }

        /* Queue the request */
        dev_hold(req->net_dev = net_dev);
        INIT_WORK(&req->work, efx_filter_rfs_work);
        req->rxq_index = rxq_index;
        req->flow_id = flow_id;
        schedule_work(&req->work);
        return rc;
out_unlock:
        spin_unlock(&efx->rps_hash_lock);
out_clear:
        clear_bit(slot_idx, &efx->rps_slot_map);
        return rc;
}

bool __efx_filter_rfs_expire(struct efx_channel *channel, unsigned int quota)
{
        bool (*expire_one)(struct efx_nic *efx, u32 flow_id, unsigned int index);
        struct efx_nic *efx = channel->efx;
        unsigned int index, size, start;
        u32 flow_id;

        if (!mutex_trylock(&efx->rps_mutex))
                return false;
        expire_one = efx->type->filter_rfs_expire_one;
        index = channel->rfs_expire_index;
        start = index;
        size = efx->type->max_rx_ip_filters;
        while (quota) {
                flow_id = channel->rps_flow_id[index];

                if (flow_id != RPS_FLOW_ID_INVALID) {
                        quota--;
                        if (expire_one(efx, flow_id, index)) {
                                netif_info(efx, rx_status, efx->net_dev,
                                           "expired filter %d [channel %u flow %u]\n",
                                           index, channel->channel, flow_id);
                                channel->rps_flow_id[index] = RPS_FLOW_ID_INVALID;
                                channel->rfs_filter_count--;
                        }
                }
                if (++index == size)
                        index = 0;
                /* If we were called with a quota that exceeds the total number
                 * of filters in the table (which shouldn't happen, but could
                 * if two callers race), ensure that we don't loop forever -
                 * stop when we've examined every row of the table.
                 */
                if (index == start)
                        break;
        }

        channel->rfs_expire_index = index;
        mutex_unlock(&efx->rps_mutex);
        return true;
}

#endif /* CONFIG_RFS_ACCEL */