// SPDX-License-Identifier: GPL-2.0

#include <linux/netdevice.h>
#include <net/netdev_lock.h>
#include <net/xsk_buff_pool.h>
#include <net/xdp_sock.h>
#include <net/xdp_sock_drv.h>

#include "xsk_queue.h"
#include "xdp_umem.h"
#include "xsk.h"

void xp_add_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
{
        if (!xs->tx)
                return;

        spin_lock(&pool->xsk_tx_list_lock);
        list_add_rcu(&xs->tx_list, &pool->xsk_tx_list);
        spin_unlock(&pool->xsk_tx_list_lock);
}

void xp_del_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
{
        if (!xs->tx)
                return;

        spin_lock(&pool->xsk_tx_list_lock);
        list_del_rcu(&xs->tx_list);
        spin_unlock(&pool->xsk_tx_list_lock);
}

void xp_destroy(struct xsk_buff_pool *pool)
{
        if (!pool)
                return;

        kvfree(pool->tx_descs);
        kvfree(pool->heads);
        kvfree(pool);
}

int xp_alloc_tx_descs(struct xsk_buff_pool *pool, struct xdp_sock *xs)
{
        pool->tx_descs = kvzalloc_objs(*pool->tx_descs, xs->tx->nentries);
        if (!pool->tx_descs)
                return -ENOMEM;

        return 0;
}

struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
                                                struct xdp_umem *umem)
{
        bool unaligned = umem->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
        struct xsk_buff_pool *pool;
        struct xdp_buff_xsk *xskb;
        u32 i, entries;

        entries = unaligned ? umem->chunks : 0;
        pool = kvzalloc_flex(*pool, free_heads, entries);
        if (!pool)
                goto out;

        pool->heads = kvzalloc_objs(*pool->heads, umem->chunks);
        if (!pool->heads)
                goto out;

        if (xs->tx)
                if (xp_alloc_tx_descs(pool, xs))
                        goto out;

        pool->chunk_mask = ~((u64)umem->chunk_size - 1);
        pool->addrs_cnt = umem->size;
        pool->heads_cnt = umem->chunks;
        pool->free_heads_cnt = umem->chunks;
        pool->headroom = umem->headroom;
        pool->chunk_size = umem->chunk_size;
        pool->chunk_shift = ffs(umem->chunk_size) - 1;
        pool->unaligned = unaligned;
        pool->frame_len = umem->chunk_size - umem->headroom -
                XDP_PACKET_HEADROOM;
        pool->umem = umem;
        pool->addrs = umem->addrs;
        pool->tx_metadata_len = umem->tx_metadata_len;
        pool->tx_sw_csum = umem->flags & XDP_UMEM_TX_SW_CSUM;
        spin_lock_init(&pool->rx_lock);
        INIT_LIST_HEAD(&pool->free_list);
        INIT_LIST_HEAD(&pool->xskb_list);
        INIT_LIST_HEAD(&pool->xsk_tx_list);
        spin_lock_init(&pool->xsk_tx_list_lock);
        spin_lock_init(&pool->cq_prod_lock);
        spin_lock_init(&xs->cq_tmp->cq_cached_prod_lock);
        refcount_set(&pool->users, 1);

        pool->fq = xs->fq_tmp;
        pool->cq = xs->cq_tmp;

        for (i = 0; i < pool->free_heads_cnt; i++) {
                xskb = &pool->heads[i];
                xskb->pool = pool;
                xskb->xdp.frame_sz = umem->chunk_size - umem->headroom;
                INIT_LIST_HEAD(&xskb->list_node);
                if (pool->unaligned)
                        pool->free_heads[i] = xskb;
                else
                        xp_init_xskb_addr(xskb, pool, (u64)i * pool->chunk_size);
        }

        return pool;

out:
        xp_destroy(pool);
        return NULL;
}

void xp_set_rxq_info(struct xsk_buff_pool *pool, struct xdp_rxq_info *rxq)
{
        u32 i;

        for (i = 0; i < pool->heads_cnt; i++)
                pool->heads[i].xdp.rxq = rxq;
}
EXPORT_SYMBOL(xp_set_rxq_info);

void xp_fill_cb(struct xsk_buff_pool *pool, struct xsk_cb_desc *desc)
{
        u32 i;

        for (i = 0; i < pool->heads_cnt; i++) {
                struct xdp_buff_xsk *xskb = &pool->heads[i];

                memcpy(xskb->cb + desc->off, desc->src, desc->bytes);
        }
}
EXPORT_SYMBOL(xp_fill_cb);

static void xp_disable_drv_zc(struct xsk_buff_pool *pool)
{
        struct netdev_bpf bpf;
        int err;

        ASSERT_RTNL();

        if (pool->umem->zc) {
                bpf.command = XDP_SETUP_XSK_POOL;
                bpf.xsk.pool = NULL;
                bpf.xsk.queue_id = pool->queue_id;

                err = pool->netdev->netdev_ops->ndo_bpf(pool->netdev, &bpf);

                if (err)
                        WARN(1, "Failed to disable zero-copy!\n");
        }
}

int xp_assign_dev(struct xsk_buff_pool *pool,
                  struct net_device *netdev, u16 queue_id, u16 flags)
{
        bool force_zc, force_copy;
        struct netdev_bpf bpf;
        int err = 0;

        ASSERT_RTNL();

        force_zc = flags & XDP_ZEROCOPY;
        force_copy = flags & XDP_COPY;

        if (force_zc && force_copy)
                return -EINVAL;

        if (xsk_get_pool_from_qid(netdev, queue_id))
                return -EBUSY;

        pool->netdev = netdev;
        pool->queue_id = queue_id;
        err = xsk_reg_pool_at_qid(netdev, pool, queue_id);
        if (err)
                return err;

        if (flags & XDP_USE_SG)
                pool->umem->flags |= XDP_UMEM_SG_FLAG;

        if (flags & XDP_USE_NEED_WAKEUP)
                pool->uses_need_wakeup = true;
        /* Tx needs to be explicitly woken up the first time.  Also
         * for supporting drivers that do not implement this
         * feature. They will always have to call sendto() or poll().
         */
        pool->cached_need_wakeup = XDP_WAKEUP_TX;

        dev_hold(netdev);

        if (force_copy)
                /* For copy-mode, we are done. */
                return 0;

        if ((netdev->xdp_features & NETDEV_XDP_ACT_XSK) != NETDEV_XDP_ACT_XSK) {
                err = -EOPNOTSUPP;
                goto err_unreg_pool;
        }

        if (netdev->xdp_zc_max_segs == 1 && (flags & XDP_USE_SG)) {
                err = -EOPNOTSUPP;
                goto err_unreg_pool;
        }

        if (dev_get_min_mp_channel_count(netdev)) {
                err = -EBUSY;
                goto err_unreg_pool;
        }

        bpf.command = XDP_SETUP_XSK_POOL;
        bpf.xsk.pool = pool;
        bpf.xsk.queue_id = queue_id;

        netdev_ops_assert_locked(netdev);
        err = netdev->netdev_ops->ndo_bpf(netdev, &bpf);
        if (err)
                goto err_unreg_pool;

        if (!pool->dma_pages) {
                WARN(1, "Driver did not DMA map zero-copy buffers");
                err = -EINVAL;
                goto err_unreg_xsk;
        }
        pool->umem->zc = true;
        pool->xdp_zc_max_segs = netdev->xdp_zc_max_segs;
        return 0;

err_unreg_xsk:
        xp_disable_drv_zc(pool);
err_unreg_pool:
        if (!force_zc)
                err = 0; /* fallback to copy mode */
        if (err) {
                xsk_clear_pool_at_qid(netdev, queue_id);
                dev_put(netdev);
        }
        return err;
}

int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_sock *umem_xs,
                         struct net_device *dev, u16 queue_id)
{
        u16 flags;
        struct xdp_umem *umem = umem_xs->umem;

        flags = umem->zc ? XDP_ZEROCOPY : XDP_COPY;
        if (umem_xs->pool->uses_need_wakeup)
                flags |= XDP_USE_NEED_WAKEUP;

        return xp_assign_dev(pool, dev, queue_id, flags);
}

void xp_clear_dev(struct xsk_buff_pool *pool)
{
        struct net_device *netdev = pool->netdev;

        if (!pool->netdev)
                return;

        netdev_lock_ops(netdev);
        xp_disable_drv_zc(pool);
        xsk_clear_pool_at_qid(pool->netdev, pool->queue_id);
        pool->netdev = NULL;
        netdev_unlock_ops(netdev);
        dev_put(netdev);
}

static void xp_release_deferred(struct work_struct *work)
{
        struct xsk_buff_pool *pool = container_of(work, struct xsk_buff_pool,
                                                  work);

        rtnl_lock();
        xp_clear_dev(pool);
        rtnl_unlock();

        if (pool->fq) {
                xskq_destroy(pool->fq);
                pool->fq = NULL;
        }

        if (pool->cq) {
                xskq_destroy(pool->cq);
                pool->cq = NULL;
        }

        xdp_put_umem(pool->umem, false);
        xp_destroy(pool);
}

void xp_get_pool(struct xsk_buff_pool *pool)
{
        refcount_inc(&pool->users);
}

bool xp_put_pool(struct xsk_buff_pool *pool)
{
        if (!pool)
                return false;

        if (refcount_dec_and_test(&pool->users)) {
                INIT_WORK(&pool->work, xp_release_deferred);
                schedule_work(&pool->work);
                return true;
        }

        return false;
}

static struct xsk_dma_map *xp_find_dma_map(struct xsk_buff_pool *pool)
{
        struct xsk_dma_map *dma_map;

        list_for_each_entry(dma_map, &pool->umem->xsk_dma_list, list) {
                if (dma_map->netdev == pool->netdev)
                        return dma_map;
        }

        return NULL;
}

static struct xsk_dma_map *xp_create_dma_map(struct device *dev, struct net_device *netdev,
                                             u32 nr_pages, struct xdp_umem *umem)
{
        struct xsk_dma_map *dma_map;

        dma_map = kzalloc_obj(*dma_map);
        if (!dma_map)
                return NULL;

        dma_map->dma_pages = kvzalloc_objs(*dma_map->dma_pages, nr_pages);
        if (!dma_map->dma_pages) {
                kfree(dma_map);
                return NULL;
        }

        dma_map->netdev = netdev;
        dma_map->dev = dev;
        dma_map->dma_pages_cnt = nr_pages;
        refcount_set(&dma_map->users, 1);
        list_add(&dma_map->list, &umem->xsk_dma_list);
        return dma_map;
}

static void xp_destroy_dma_map(struct xsk_dma_map *dma_map)
{
        list_del(&dma_map->list);
        kvfree(dma_map->dma_pages);
        kfree(dma_map);
}

static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs)
{
        dma_addr_t *dma;
        u32 i;

        for (i = 0; i < dma_map->dma_pages_cnt; i++) {
                dma = &dma_map->dma_pages[i];
                if (*dma) {
                        *dma &= ~XSK_NEXT_PG_CONTIG_MASK;
                        dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,
                                             DMA_BIDIRECTIONAL, attrs);
                        *dma = 0;
                }
        }

        xp_destroy_dma_map(dma_map);
}

void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs)
{
        struct xsk_dma_map *dma_map;

        if (!pool->dma_pages)
                return;

        dma_map = xp_find_dma_map(pool);
        if (!dma_map) {
                WARN(1, "Could not find dma_map for device");
                return;
        }

        if (refcount_dec_and_test(&dma_map->users))
                __xp_dma_unmap(dma_map, attrs);

        kvfree(pool->dma_pages);
        pool->dma_pages = NULL;
        pool->dma_pages_cnt = 0;
        pool->dev = NULL;
}
EXPORT_SYMBOL(xp_dma_unmap);

static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)
{
        u32 i;

        for (i = 0; i < dma_map->dma_pages_cnt - 1; i++) {
                if (dma_map->dma_pages[i] + PAGE_SIZE == dma_map->dma_pages[i + 1])
                        dma_map->dma_pages[i] |= XSK_NEXT_PG_CONTIG_MASK;
                else
                        dma_map->dma_pages[i] &= ~XSK_NEXT_PG_CONTIG_MASK;
        }
}

static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_map)
{
        if (!pool->unaligned) {
                u32 i;

                for (i = 0; i < pool->heads_cnt; i++) {
                        struct xdp_buff_xsk *xskb = &pool->heads[i];
                        u64 orig_addr;

                        orig_addr = xskb->xdp.data_hard_start - pool->addrs - pool->headroom;
                        xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, orig_addr);
                }
        }

        pool->dma_pages = kvzalloc_objs(*pool->dma_pages,
                                        dma_map->dma_pages_cnt);
        if (!pool->dma_pages)
                return -ENOMEM;

        pool->dev = dma_map->dev;
        pool->dma_pages_cnt = dma_map->dma_pages_cnt;
        memcpy(pool->dma_pages, dma_map->dma_pages,
               pool->dma_pages_cnt * sizeof(*pool->dma_pages));

        return 0;
}

int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
               unsigned long attrs, struct page **pages, u32 nr_pages)
{
        struct xsk_dma_map *dma_map;
        dma_addr_t dma;
        int err;
        u32 i;

        dma_map = xp_find_dma_map(pool);
        if (dma_map) {
                err = xp_init_dma_info(pool, dma_map);
                if (err)
                        return err;

                refcount_inc(&dma_map->users);
                return 0;
        }

        dma_map = xp_create_dma_map(dev, pool->netdev, nr_pages, pool->umem);
        if (!dma_map)
                return -ENOMEM;

        for (i = 0; i < dma_map->dma_pages_cnt; i++) {
                dma = dma_map_page_attrs(dev, pages[i], 0, PAGE_SIZE,
                                         DMA_BIDIRECTIONAL, attrs);
                if (dma_mapping_error(dev, dma)) {
                        __xp_dma_unmap(dma_map, attrs);
                        return -ENOMEM;
                }
                dma_map->dma_pages[i] = dma;
        }

        if (pool->unaligned)
                xp_check_dma_contiguity(dma_map);

        err = xp_init_dma_info(pool, dma_map);
        if (err) {
                __xp_dma_unmap(dma_map, attrs);
                return err;
        }

        return 0;
}
EXPORT_SYMBOL(xp_dma_map);

static bool xp_addr_crosses_non_contig_pg(struct xsk_buff_pool *pool,
                                          u64 addr)
{
        return xp_desc_crosses_non_contig_pg(pool, addr, pool->chunk_size);
}

static bool xp_check_unaligned(struct xsk_buff_pool *pool, u64 *addr)
{
        *addr = xp_unaligned_extract_addr(*addr);
        if (*addr >= pool->addrs_cnt ||
            *addr + pool->chunk_size > pool->addrs_cnt ||
            xp_addr_crosses_non_contig_pg(pool, *addr))
                return false;
        return true;
}

static bool xp_check_aligned(struct xsk_buff_pool *pool, u64 *addr)
{
        *addr = xp_aligned_extract_addr(pool, *addr);
        return *addr < pool->addrs_cnt;
}

static struct xdp_buff_xsk *xp_get_xskb(struct xsk_buff_pool *pool, u64 addr)
{
        struct xdp_buff_xsk *xskb;

        if (pool->unaligned) {
                xskb = pool->free_heads[--pool->free_heads_cnt];
                xp_init_xskb_addr(xskb, pool, addr);
                if (pool->dma_pages)
                        xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr);
        } else {
                xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)];
        }

        return xskb;
}

static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
{
        struct xdp_buff_xsk *xskb;
        u64 addr;
        bool ok;

        if (pool->free_heads_cnt == 0)
                return NULL;

        for (;;) {
                if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
                        pool->fq->queue_empty_descs++;
                        return NULL;
                }

                ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
                     xp_check_aligned(pool, &addr);
                if (!ok) {
                        pool->fq->invalid_descs++;
                        xskq_cons_release(pool->fq);
                        continue;
                }
                break;
        }

        xskb = xp_get_xskb(pool, addr);

        xskq_cons_release(pool->fq);
        return xskb;
}

struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
{
        struct xdp_buff_xsk *xskb;

        if (!pool->free_list_cnt) {
                xskb = __xp_alloc(pool);
                if (!xskb)
                        return NULL;
        } else {
                pool->free_list_cnt--;
                xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk,
                                        list_node);
                list_del_init(&xskb->list_node);
        }

        xskb->xdp.data = xskb->xdp.data_hard_start + XDP_PACKET_HEADROOM;
        xskb->xdp.data_meta = xskb->xdp.data;
        xskb->xdp.flags = 0;

        if (pool->dev)
                xp_dma_sync_for_device(pool, xskb->dma, pool->frame_len);

        return &xskb->xdp;
}
EXPORT_SYMBOL(xp_alloc);

static u32 xp_alloc_new_from_fq(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
{
        u32 i, cached_cons, nb_entries;

        if (max > pool->free_heads_cnt)
                max = pool->free_heads_cnt;
        max = xskq_cons_nb_entries(pool->fq, max);

        cached_cons = pool->fq->cached_cons;
        nb_entries = max;
        i = max;
        while (i--) {
                struct xdp_buff_xsk *xskb;
                u64 addr;
                bool ok;

                __xskq_cons_read_addr_unchecked(pool->fq, cached_cons++, &addr);

                ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
                        xp_check_aligned(pool, &addr);
                if (unlikely(!ok)) {
                        pool->fq->invalid_descs++;
                        nb_entries--;
                        continue;
                }

                xskb = xp_get_xskb(pool, addr);

                *xdp = &xskb->xdp;
                xdp++;
        }

        xskq_cons_release_n(pool->fq, max);
        return nb_entries;
}

static u32 xp_alloc_reused(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 nb_entries)
{
        struct xdp_buff_xsk *xskb;
        u32 i;

        nb_entries = min_t(u32, nb_entries, pool->free_list_cnt);

        i = nb_entries;
        while (i--) {
                xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk, list_node);
                list_del_init(&xskb->list_node);

                *xdp = &xskb->xdp;
                xdp++;
        }
        pool->free_list_cnt -= nb_entries;

        return nb_entries;
}

static u32 xp_alloc_slow(struct xsk_buff_pool *pool, struct xdp_buff **xdp,
                         u32 max)
{
        int i;

        for (i = 0; i < max; i++) {
                struct xdp_buff *buff;

                buff = xp_alloc(pool);
                if (unlikely(!buff))
                        return i;
                *xdp = buff;
                xdp++;
        }

        return max;
}

u32 xp_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
{
        u32 nb_entries1 = 0, nb_entries2;

        if (unlikely(pool->dev && dma_dev_need_sync(pool->dev)))
                return xp_alloc_slow(pool, xdp, max);

        if (unlikely(pool->free_list_cnt)) {
                nb_entries1 = xp_alloc_reused(pool, xdp, max);
                if (nb_entries1 == max)
                        return nb_entries1;

                max -= nb_entries1;
                xdp += nb_entries1;
        }

        nb_entries2 = xp_alloc_new_from_fq(pool, xdp, max);
        if (!nb_entries2)
                pool->fq->queue_empty_descs++;

        return nb_entries1 + nb_entries2;
}
EXPORT_SYMBOL(xp_alloc_batch);

bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count)
{
        u32 req_count, avail_count;

        if (pool->free_list_cnt >= count)
                return true;

        req_count = count - pool->free_list_cnt;
        avail_count = xskq_cons_nb_entries(pool->fq, req_count);
        if (!avail_count)
                pool->fq->queue_empty_descs++;

        return avail_count >= req_count;
}
EXPORT_SYMBOL(xp_can_alloc);

void xp_free(struct xdp_buff_xsk *xskb)
{
        if (!list_empty(&xskb->list_node))
                return;

        xskb->pool->free_list_cnt++;
        list_add(&xskb->list_node, &xskb->pool->free_list);
}
EXPORT_SYMBOL(xp_free);

static u64 __xp_raw_get_addr(const struct xsk_buff_pool *pool, u64 addr)
{
        return pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
}

static void *__xp_raw_get_data(const struct xsk_buff_pool *pool, u64 addr)
{
        return pool->addrs + addr;
}

void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
{
        return __xp_raw_get_data(pool, __xp_raw_get_addr(pool, addr));
}
EXPORT_SYMBOL(xp_raw_get_data);

static dma_addr_t __xp_raw_get_dma(const struct xsk_buff_pool *pool, u64 addr)
{
        return (pool->dma_pages[addr >> PAGE_SHIFT] &
                ~XSK_NEXT_PG_CONTIG_MASK) +
                (addr & ~PAGE_MASK);
}

dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
{
        return __xp_raw_get_dma(pool, __xp_raw_get_addr(pool, addr));
}
EXPORT_SYMBOL(xp_raw_get_dma);

/**
 * xp_raw_get_ctx - get &xdp_desc context
 * @pool: XSk buff pool desc address belongs to
 * @addr: desc address (from userspace)
 *
 * Helper for getting desc's DMA address and metadata pointer, if present.
 * Saves one call on hotpath, double calculation of the actual address,
 * and inline checks for metadata presence and sanity.
 *
 * Return: new &xdp_desc_ctx struct containing desc's DMA address and metadata
 * pointer, if it is present and valid (initialized to %NULL otherwise).
 */
struct xdp_desc_ctx xp_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr)
{
        struct xdp_desc_ctx ret;

        addr = __xp_raw_get_addr(pool, addr);

        ret.dma = __xp_raw_get_dma(pool, addr);
        ret.meta = __xsk_buff_get_metadata(pool, __xp_raw_get_data(pool, addr));

        return ret;
}
EXPORT_SYMBOL(xp_raw_get_ctx);