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Message-ID: <CALDO+SYYVW6xP-ECMJvapGoPHxfh4w0JeSX-aapQd3cB3gWLUg@mail.gmail.com>
Date: Tue, 3 Jan 2023 13:52:34 -0800
From: William Tu <u9012063@...il.com>
To: Alexander Lobakin <alexandr.lobakin@...el.com>
Cc: netdev@...r.kernel.org, tuc@...are.com, gyang@...are.com,
doshir@...are.com, alexander.duyck@...il.com,
gerhard@...leder-embedded.com
Subject: Re: [PATCH v8] vmxnet3: Add XDP support.
Hi Alexander,
Thanks for your feedback!
On Tue, Jan 3, 2023 at 7:46 AM Alexander Lobakin
<alexandr.lobakin@...el.com> wrote:
>
> From: William Tu <u9012063@...il.com>
> Date: Mon, 2 Jan 2023 18:22:32 -0800
>
> > The patch adds native-mode XDP support: XDP DROP, PASS, TX, and REDIRECT.
>
> [...]
>
> > @@ -332,9 +333,12 @@ vmxnet3_unmap_tx_buf(struct vmxnet3_tx_buf_info *tbi,
> > else if (tbi->map_type == VMXNET3_MAP_PAGE)
> > dma_unmap_page(&pdev->dev, tbi->dma_addr, tbi->len,
> > DMA_TO_DEVICE);
> > + else if (tbi->map_type == VMXNET3_MAP_PP_PAGE && tbi->xdpf)
> > + xdp_return_frame(tbi->xdpf);
> > + else if (tbi->map_type == VMXNET3_MAP_XDP_NDO && tbi->xdpf)
> > + xdp_return_frame(tbi->xdpf);
>
> Have you looked at xdp_return_frame_bulk()? It flushes frames in
> bulks of 16, so it can be faster here.
Sure will do it.
I think I just need to accumulate more frames in vmxnet3_unmap_pkt
and call xdp_return_frame_bulk.
>
> Also, those 2 branches do the same stuff, so just squash them into
> one with ||.
good catch, thanks!
>
> > else
> > BUG_ON(tbi->map_type != VMXNET3_MAP_NONE);
> > -
> > tbi->map_type = VMXNET3_MAP_NONE; /* to help debugging */
> > }
>
> [...]
>
> > @@ -1253,6 +1266,46 @@ vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
> > return NETDEV_TX_OK;
> > }
> >
> > +static int
> > +vmxnet3_create_pp(struct vmxnet3_adapter *adapter,
> > + struct vmxnet3_rx_queue *rq, int size)
> > +{
> > + struct page_pool_params pp_params = {
>
> const?
Yes!
>
> > + .order = 0,
> > + .flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
> > + .pool_size = size,
> > + .nid = NUMA_NO_NODE,
> > + .dev = &adapter->pdev->dev,
> > + .offset = XDP_PACKET_HEADROOM,
> > + .max_len = VMXNET3_XDP_MAX_MTU,
> > + .dma_dir = DMA_BIDIRECTIONAL,
> > + };
> > + struct page_pool *pp;
> > + int err;
> > +
> > + pp = page_pool_create(&pp_params);
> > + if (IS_ERR(pp))
> > + return PTR_ERR(pp);
>
> [...]
>
> > +static void
> > +vmxnet3_pp_put_buff(struct vmxnet3_rx_queue *rq, struct page *page)
> > +{
> > + if (rq->page_pool)
> > + page_pool_put_full_page(rq->page_pool, page,
> > + rq->napi.napi_id);
>
> Wait, ::napi_id as `bool allow_direct`? Is that intentional (if so,
> a short comment would be useful here)?
That's a mistake, sorry. Will fix it.
>
> > +}
> >
> > static void
> > vmxnet3_rx_csum(struct vmxnet3_adapter *adapter,
>
> [...]
>
> > @@ -1485,9 +1586,7 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
> >
> > if (rxDataRingUsed) {
> > size_t sz;
> > -
> > BUG_ON(rcd->len > rq->data_ring.desc_size);
> > -
>
> ??? Why are those 2 nl removals here? The code looks prettier with
> them and they are not related to the patch subject.
My mistake, will fix it.
>
> > ctx->skb = new_skb;
> > sz = rcd->rxdIdx * rq->data_ring.desc_size;
> > memcpy(new_skb->data,
>
> [...]
>
> > @@ -1730,6 +1829,8 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
> > vmxnet3_getRxComp(rcd,
> > &rq->comp_ring.base[rq->comp_ring.next2proc].rcd, &rxComp);
> > }
> > + if (need_flush)
> > + xdp_do_flush_map();
>
> From [0]:
>
> "do not use xdp_do_flush_map() in new code!"
> "#define xdp_do_flush_map xdp_do_flush"
OK! will do it.
>
> >
> > return num_pkts;
> > }
> > @@ -1753,8 +1854,14 @@ vmxnet3_rq_cleanup(struct vmxnet3_rx_queue *rq,
> > #endif
> > vmxnet3_getRxDesc(rxd,
> > &rq->rx_ring[ring_idx].base[i].rxd, &rxDesc);
> > -
>
> Also '???'.
mistake! will fix it.
>
> > if (rxd->btype == VMXNET3_RXD_BTYPE_HEAD &&
> > + rq->buf_info[ring_idx][i].pp_page &&
> > + rq->buf_info[ring_idx][i].buf_type ==
> > + VMXNET3_RX_BUF_XDP) {
>
> Please align that line to the opening brace, just like the previous
> ones.
OK
>
> > + vmxnet3_pp_put_buff(rq,
> > + rq->buf_info[ring_idx][i].pp_page);
> > + rq->buf_info[ring_idx][i].pp_page = NULL;
> > + } else if (rxd->btype == VMXNET3_RXD_BTYPE_HEAD &&
> > rq->buf_info[ring_idx][i].skb) {
>
> Could you maybe align that one too while at it?
OK
I will make sure they all aligned.
>
> > dma_unmap_single(&adapter->pdev->dev, rxd->addr,
> > rxd->len, DMA_FROM_DEVICE);
>
> [...]
>
> > @@ -1858,14 +1972,15 @@ static int
> > vmxnet3_rq_init(struct vmxnet3_rx_queue *rq,
> > struct vmxnet3_adapter *adapter)
> > {
> > - int i;
> > + int i, err = 0;
>
> That assignment to zero is redundant I believe, you use that var
> only to store the return value of vmxnet3_create_pp() and return
> it in place, so there are no ways to use that zero value.
Yes, will fix it
>
> >
> > /* initialize buf_info */
> > for (i = 0; i < rq->rx_ring[0].size; i++) {
>
> [...]
>
> > @@ -2585,7 +2707,8 @@ vmxnet3_setup_driver_shared(struct vmxnet3_adapter *adapter)
> > if (adapter->netdev->features & NETIF_F_RXCSUM)
> > devRead->misc.uptFeatures |= UPT1_F_RXCSUM;
> >
> > - if (adapter->netdev->features & NETIF_F_LRO) {
> > + if (adapter->netdev->features & NETIF_F_LRO &&
>
> I'd recommend to enclose bitwise ops in their own set of braces ()
> when there are logical ops nearby, some compilers even warn about
> that in some cases.
Thanks! will do it.
>
> > + !adapter->xdp_enabled) {
> > devRead->misc.uptFeatures |= UPT1_F_LRO;
> > devRead->misc.maxNumRxSG = cpu_to_le16(1 + MAX_SKB_FRAGS);
> > }
>
> [...]
>
> > @@ -3900,6 +4025,7 @@ vmxnet3_probe_device(struct pci_dev *pdev,
> > goto err_register;
> > }
> >
> > + adapter->xdp_enabled = false;
>
> alloc_etherdev_mq() (-> alloc_netdev_mqs()) allocates a zeroed
> memory chunk, so this is redundant.
I see, thanks!
>
> > vmxnet3_check_link(adapter, false);
> > return 0;
>
> [...]
>
> > @@ -201,6 +206,7 @@ struct vmxnet3_tx_buf_info {
> > u16 sop_idx;
> > dma_addr_t dma_addr;
> > struct sk_buff *skb;
> > + struct xdp_frame *xdpf;
>
> How about a union with those two? They're mutually exclusive, aren't
> they?
Yes, they are.
I did think about making it a union but I have to introduce addition
code to check tbi->map_type.
ex: there are existing codes doing
if (tbi->skb) {
dev_kfree_skb_any(tbi->skb);
tbi->skb = NULL;
}
Let me try and see how it looks.
>
> > };
> >
> > struct vmxnet3_tq_driver_stats {
>
> [...]
>
> > @@ -307,6 +324,8 @@ struct vmxnet3_rx_queue {
> > struct vmxnet3_rx_buf_info *buf_info[2];
> > struct Vmxnet3_RxQueueCtrl *shared;
> > struct vmxnet3_rq_driver_stats stats;
> > + struct xdp_rxq_info xdp_rxq;
>
> &xdp_rxq_info is cacheline-aligned and is big enough, they are
> usually placed at the end of a queue structure.
I didn't notice that, thanks.
>
> > + struct page_pool *page_pool;
> > } __attribute__((__aligned__(SMP_CACHE_BYTES)));
>
> (unrelated) -> ____cacheline_aligned
Will do.
>
> >
> > #define VMXNET3_DEVICE_MAX_TX_QUEUES 32
> > @@ -415,6 +434,8 @@ struct vmxnet3_adapter {
> > u16 tx_prod_offset;
> > u16 rx_prod_offset;
> > u16 rx_prod2_offset;
> > + bool xdp_enabled;
>
> Nit: consider introducing something like
>
> u32 xdp_enabled:1;
>
> or
>
> u32 flags;
> #define VMXNET3_XDP_ENABLED BIT(0)
>
> or whatever prefer. bools are slippery to use in structures (you'd
> also save 31 bits for more flags in future instead of occupying 8-32
> bits for just one flag).
Good point.
>
> > + struct bpf_prog __rcu *xdp_bpf_prog;
>
> Or maybe you could omit the flag above completely and check whether
> XDP is enabled via `!!rcu_access_pointer(ring->xdp_bpf_prog)`?
Sure, I think that's better.
>
> > };
> >
> > #define VMXNET3_WRITE_BAR0_REG(adapter, reg, val) \
>
> [...]
>
> > +static void
> > +vmxnet3_xdp_exchange_program(struct vmxnet3_adapter *adapter,
> > + struct bpf_prog *prog)
> > +{
> > + rcu_assign_pointer(adapter->xdp_bpf_prog, prog);
> > + if (prog)
> > + adapter->xdp_enabled = true;
> > + else
> > + adapter->xdp_enabled = false;
>
> adapter->xdp_enabled = !!prog;
>
> > +}
> > +
> > +static int
> > +vmxnet3_xdp_set(struct net_device *netdev, struct netdev_bpf *bpf,
> > + struct netlink_ext_ack *extack)
> > +{
> > + struct vmxnet3_adapter *adapter = netdev_priv(netdev);
> > + struct bpf_prog *new_bpf_prog = bpf->prog;
> > + struct bpf_prog *old_bpf_prog;
> > + bool need_update;
> > + bool running;
> > + int err = 0;
> > +
> > + if (new_bpf_prog && netdev->mtu > VMXNET3_XDP_MAX_MTU) {
> > + NL_SET_ERR_MSG_MOD(extack, "MTU too large for XDP");
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + old_bpf_prog = READ_ONCE(adapter->rx_queue[0].adapter->xdp_bpf_prog);
>
> Doesn't the @adapter variable above points to the same struct you
> are accessing here?
another mistake, will fix it.
>
> > + if (!new_bpf_prog && !old_bpf_prog) {
> > + adapter->xdp_enabled = false;
> > + return 0;
> > + }
> > + running = netif_running(netdev);
> > + need_update = !!old_bpf_prog != !!new_bpf_prog;
> > +
> > + if (running && need_update)
> > + vmxnet3_quiesce_dev(adapter);
> > +
> > + vmxnet3_xdp_exchange_program(adapter, new_bpf_prog);
> > + if (old_bpf_prog)
> > + bpf_prog_put(old_bpf_prog);
> > +
> > + if (running && need_update) {
>
> if (!running || !need_update)
> return 0;
>
> -1 indent level.
good idea.
>
> > + vmxnet3_reset_dev(adapter);
> > + vmxnet3_rq_destroy_all(adapter);
> > + vmxnet3_adjust_rx_ring_size(adapter);
> > + err = vmxnet3_rq_create_all(adapter);
> > + if (err) {
> > + NL_SET_ERR_MSG_MOD(extack,
> > + "failed to re-create rx queues for XDP.");
> > + err = -EOPNOTSUPP;
> > + goto out;
> > + }
> > + err = vmxnet3_activate_dev(adapter);
> > + if (err) {
> > + NL_SET_ERR_MSG_MOD(extack,
> > + "failed to activate device for XDP.");
> > + err = -EOPNOTSUPP;
> > + goto out;
> > + }
> > + clear_bit(VMXNET3_STATE_BIT_RESETTING, &adapter->state);
> > + }
> > +out:
> > + return err;
>
> Please avoid oneliner labels, you can do `return err` right where
> you goto here.
Thanks, will fix it.
>
> > +}
> > +
> > +/* This is the main xdp call used by kernel to set/unset eBPF program. */
> > +int
> > +vmxnet3_xdp(struct net_device *netdev, struct netdev_bpf *bpf)
> > +{
> > + switch (bpf->command) {
> > + case XDP_SETUP_PROG:
> > + netdev_dbg(netdev, "XDP: set program to ");
>
> Is it still relevant?
no, will remove it.
>
> > + return vmxnet3_xdp_set(netdev, bpf, bpf->extack);
> > + default:
> > + return -EINVAL;
> > + }
> > + return 0;
> > +}
> > +
> > +int
> > +vmxnet3_xdp_headroom(struct vmxnet3_adapter *adapter)
> > +{
> > + if (adapter->xdp_enabled)
> > + return VMXNET3_XDP_ROOM;
>
> This is confusing. %VMXNET3_XDP_ROOM includes &skb_shared_info's
> size. So the function returns not a headroom, rather kernel (XDP +
> skb) overhead.
right, I will rename it to VMXNET3_XDP_PAD, as padding.
>
> > + else
> > + return 0;
>
> return adapter->xdp_enabled ? VMXNET3_XDP_ROOM : 0;
yes, that's cleaner.
>
> > +}
> > +
>
> Those two functions:
>
> /start
>
> > +void
> > +vmxnet3_unregister_xdp_rxq(struct vmxnet3_rx_queue *rq)
> > +{
> > + xdp_rxq_info_unreg_mem_model(&rq->xdp_rxq);
> > + xdp_rxq_info_unreg(&rq->xdp_rxq);
> > +}
> > +
> > +int
> > +vmxnet3_register_xdp_rxq(struct vmxnet3_rx_queue *rq,
> > + struct vmxnet3_adapter *adapter)
> > +{
> > + int err;
> > +
> > + err = xdp_rxq_info_reg(&rq->xdp_rxq, adapter->netdev, rq->qid, 0);
> > + if (err < 0)
> > + return err;
> > +
> > + err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq, MEM_TYPE_PAGE_SHARED,
> > + NULL);
> > + if (err < 0) {
> > + xdp_rxq_info_unreg(&rq->xdp_rxq);
> > + return err;
> > + }
> > + return 0;
> > +}
>
> /end
>
> are not used anywhere, probably leftovers.
right, thanks
>
> > +
> > +static int
> > +vmxnet3_xdp_xmit_frame(struct vmxnet3_adapter *adapter,
> > + struct xdp_frame *xdpf,
> > + struct vmxnet3_tx_queue *tq, bool dma_map)
> > +{
> > + struct vmxnet3_tx_buf_info *tbi = NULL;
> > + union Vmxnet3_GenericDesc *gdesc;
> > + struct vmxnet3_tx_ctx ctx;
> > + int tx_num_deferred;
> > + struct page *page;
> > + u32 buf_size;
> > + int ret = 0;
> > + u32 dw2;
> > +
> > + dw2 = (tq->tx_ring.gen ^ 0x1) << VMXNET3_TXD_GEN_SHIFT;
> > + dw2 |= xdpf->len;
>
> Consider using FIELD_{GET,PREP}() in future for bitfields
cool, i didn't know these macros.
these might need another patch to do that.
I will leave it for future.
>
> > + ctx.sop_txd = tq->tx_ring.base + tq->tx_ring.next2fill;
> > + gdesc = ctx.sop_txd;
> > +
> > + buf_size = xdpf->len;
> > + tbi = tq->buf_info + tq->tx_ring.next2fill;
> > +
> > + if (vmxnet3_cmd_ring_desc_avail(&tq->tx_ring) == 0) {
> > + tq->stats.tx_ring_full++;
> > + ret = -ENOSPC;
> > + goto exit;
> > + }
> > +
> > + if (dma_map) { /* ndo_xdp_xmit */
> > + tbi->map_type = VMXNET3_MAP_XDP_NDO;
> > + tbi->dma_addr = dma_map_single(&adapter->pdev->dev,
> > + xdpf->data, buf_size,
> > + DMA_TO_DEVICE);
>
> Bad indent, pls align to the opening braces.
OK
>
> > + if (dma_mapping_error(&adapter->pdev->dev, tbi->dma_addr)) {
> > + ret = -EFAULT;
> > + goto exit;
> > + }
> > + tbi->xdpf = xdpf;
> > + } else { /* XDP buffer from page pool */
> > + tbi->map_type = VMXNET3_MAP_PP_PAGE;
> > + page = virt_to_head_page(xdpf->data);
> > + tbi->dma_addr = page_pool_get_dma_addr(page) +
> > + XDP_PACKET_HEADROOM;
> > + dma_sync_single_for_device(&adapter->pdev->dev,
> > + tbi->dma_addr, buf_size,
> > + DMA_BIDIRECTIONAL);
> > + tbi->skb = NULL;
> > + tbi->xdpf = xdpf;
> > + }
> > + tbi->len = buf_size;
> > +
> > + gdesc = tq->tx_ring.base + tq->tx_ring.next2fill;
> > + WARN_ON_ONCE(gdesc->txd.gen == tq->tx_ring.gen);
> > +
> > + gdesc->txd.addr = cpu_to_le64(tbi->dma_addr);
> > + gdesc->dword[2] = cpu_to_le32(dw2);
> > +
> > + /* Setup the EOP desc */
> > + gdesc->dword[3] = cpu_to_le32(VMXNET3_TXD_CQ | VMXNET3_TXD_EOP);
> > +
> > + gdesc->txd.om = 0;
> > + gdesc->txd.msscof = 0;
> > + gdesc->txd.hlen = 0;
> > + gdesc->txd.ti = 0;
> > +
> > + tx_num_deferred = le32_to_cpu(tq->shared->txNumDeferred);
> > + tq->shared->txNumDeferred += 1;
>
> ::txNum_Deferred is __le32, are you sure you can just do += 1
> without any conversion?
good cache...
I should use le32_add_cpu to add it.
>
> > + tx_num_deferred++;
> > +
> > + vmxnet3_cmd_ring_adv_next2fill(&tq->tx_ring);
> > +
> > + /* set the last buf_info for the pkt */
> > + tbi->sop_idx = ctx.sop_txd - tq->tx_ring.base;
> > +
> > + dma_wmb();
> > + gdesc->dword[2] = cpu_to_le32(le32_to_cpu(gdesc->dword[2]) ^
> > + VMXNET3_TXD_GEN);
>
> le32_replace_bits()
>
> (it's generated by a macro, so Elixir doesn't index it. Just look at
> the end of <linux/bitfield.h> if you'd like to use it)
thanks, will fix it.
>
> > + if (tx_num_deferred >= le32_to_cpu(tq->shared->txThreshold)) {
> > + tq->shared->txNumDeferred = 0;
> > + VMXNET3_WRITE_BAR0_REG(adapter,
> > + VMXNET3_REG_TXPROD + tq->qid * 8,
> > + tq->tx_ring.next2fill);
> > + }
> > +exit:
> > + return ret;
>
> Same as a bunch of lines above for oneliner labels.
OK!
>
> > +}
> > +
> > +static int
> > +vmxnet3_xdp_xmit_back(struct vmxnet3_adapter *adapter,
> > + struct xdp_frame *xdpf)
> > +{
> > + struct vmxnet3_tx_queue *tq;
> > + struct netdev_queue *nq;
> > + int err = 0, cpu;
> > + int tq_number;
> > +
> > + tq_number = adapter->num_tx_queues;
> > + cpu = smp_processor_id();
> > + tq = &adapter->tx_queue[cpu % tq_number];
> > + if (tq->stopped)
> > + return -ENETDOWN;
> > +
> > + nq = netdev_get_tx_queue(adapter->netdev, tq->qid);
> > +
> > + __netif_tx_lock(nq, cpu);
> > + err = vmxnet3_xdp_xmit_frame(adapter, xdpf, tq, false);
> > + __netif_tx_unlock(nq);
> > + return err;
> > +}
> > +
> > +/* ndo_xdp_xmit */
> > +int
> > +vmxnet3_xdp_xmit(struct net_device *dev,
> > + int n, struct xdp_frame **frames, u32 flags)
> > +{
> > + struct vmxnet3_adapter *adapter;
> > + struct vmxnet3_tx_queue *tq;
> > + struct netdev_queue *nq;
> > + int i, err, cpu;
> > + int tq_number;
> > +
> > + adapter = netdev_priv(dev);
> > +
> > + if (unlikely(test_bit(VMXNET3_STATE_BIT_QUIESCED, &adapter->state)))
> > + return -ENETDOWN;
> > + if (unlikely(test_bit(VMXNET3_STATE_BIT_RESETTING, &adapter->state)))
> > + return -EINVAL;
> > +
> > + tq_number = adapter->num_tx_queues;
> > + cpu = smp_processor_id();
> > + tq = &adapter->tx_queue[cpu % tq_number];
> > + if (tq->stopped)
> > + return -ENETDOWN;
> > +
> > + nq = netdev_get_tx_queue(adapter->netdev, tq->qid);
> > +
> > + for (i = 0; i < n; i++) {
> > + err = vmxnet3_xdp_xmit_frame(adapter, frames[i], tq, true);
> > + if (err) {
> > + tq->stats.xdp_xmit_err++;
> > + break;
> > + }
> > + }
> > + tq->stats.xdp_xmit += i;
> > +
> > + return i;
> > +}
> > +
> > +static int
> > +vmxnet3_run_xdp(struct vmxnet3_rx_queue *rq, struct xdp_buff *xdp)
> > +{
> > + struct xdp_frame *xdpf;
> > + int err;
> > + u32 act;
> > +
> > + act = bpf_prog_run_xdp(rq->adapter->xdp_bpf_prog, xdp);
> > + rq->stats.xdp_packets++;
> > +
> > + switch (act) {
> > + case XDP_PASS:
> > + goto out;
>
> Same. Just `return act` here.
Will do.
>
> > + case XDP_REDIRECT:
> > + err = xdp_do_redirect(rq->adapter->netdev, xdp,
> > + rq->adapter->xdp_bpf_prog);
> > + if (!err)
> > + rq->stats.xdp_redirects++;
> > + else
> > + rq->stats.xdp_drops++;
> > + goto out;
>
> Same here and probably a couple times below as well.
OK
>
> > + case XDP_TX:
> > + xdpf = xdp_convert_buff_to_frame(xdp);
> > + if (!xdpf || vmxnet3_xdp_xmit_back(rq->adapter, xdpf)) {
> > + rq->stats.xdp_drops++;
> > + goto out_recycle;
>
> So that label is used only once and you could probably inline it
> into here.
Sure, will do it.
>
> > + }
> > + rq->stats.xdp_tx++;
> > + goto out;
> > + default:
> > + bpf_warn_invalid_xdp_action(rq->adapter->netdev,
> > + rq->adapter->xdp_bpf_prog, act);
> > + fallthrough;
> > + case XDP_ABORTED:
> > + trace_xdp_exception(rq->adapter->netdev,
> > + rq->adapter->xdp_bpf_prog, act);
> > + rq->stats.xdp_aborted++;
> > + break;
> > + case XDP_DROP:
> > + rq->stats.xdp_drops++;
> > + break;
> > + }
> > +
> > +out_recycle:
> > + page_pool_recycle_direct(rq->page_pool,
> > + virt_to_head_page(xdp->data_hard_start));
> > +out:
> > + return act;
> > +}
> > +
> > +static struct sk_buff *
> > +vmxnet3_build_skb(struct vmxnet3_rx_queue *rq, struct page *page)
> > +{
> > + struct sk_buff *skb;
> > +
> > + if (!page)
> > + return NULL;
> > +
> > + skb = build_skb(page_address(page), PAGE_SIZE);
> > + if (unlikely(!skb)) {
> > + page_pool_put_full_page(rq->page_pool, page, true);
> > + rq->stats.rx_buf_alloc_failure++;
> > + return NULL;
> > + }
> > + return skb;
> > +}
> > +
> > +int
> > +vmxnet3_process_xdp(struct vmxnet3_adapter *adapter,
> > + struct vmxnet3_rx_queue *rq,
> > + struct Vmxnet3_RxCompDesc *rcd,
> > + struct vmxnet3_rx_buf_info *rbi,
> > + struct Vmxnet3_RxDesc *rxd,
> > + struct sk_buff **skb_xdp_pass)
> > +{
> > + struct bpf_prog *xdp_prog;
> > + dma_addr_t new_dma_addr;
> > + struct sk_buff *skb;
> > + struct xdp_buff xdp;
> > + struct page *page;
> > + void *new_data;
> > + int act;
> > +
> > + act = XDP_DROP;
> > + if (unlikely(rcd->len == 0))
> > + goto refill;
> > +
> > + page = rbi->pp_page;
> > + if (!page)
> > + goto refill;
> > +
> > + dma_sync_single_for_cpu(&adapter->pdev->dev,
> > + page_pool_get_dma_addr(page) +
> > + XDP_PACKET_HEADROOM,
> > + rcd->len,
>
> Can fit into the previous line.
will fix it, thanks.
>
> > + page_pool_get_dma_dir(rq->page_pool));
> > +
> > + xdp_init_buff(&xdp, rbi->len, &rq->xdp_rxq);
> > + xdp_prepare_buff(&xdp, page_address(page), XDP_PACKET_HEADROOM,
> > + rcd->len, false);
> > + xdp_buff_clear_frags_flag(&xdp);
> > +
> > + rcu_read_lock();
> > + xdp_prog = rcu_dereference(rq->adapter->xdp_bpf_prog);
> > + if (!xdp_prog) {
> > + rcu_read_unlock();
> > + act = XDP_PASS;
> > + goto refill;
> > + }
> > + act = vmxnet3_run_xdp(rq, &xdp);
> > + rcu_read_unlock();
> > +
> > + if (act == XDP_PASS) {
> > + skb = vmxnet3_build_skb(rq, page);
> > + if (!skb) {
> > + rq->stats.rx_buf_alloc_failure++;
> > + page_pool_recycle_direct(rq->page_pool, page);
> > + goto refill;
> > + }
> > +
> > + /* bpf prog might change len and data position. */
> > + skb_reserve(skb, xdp.data - xdp.data_hard_start);
> > + skb_put(skb, xdp.data_end - xdp.data);
> > + skb_mark_for_recycle(skb);
> > + /* Pass this skb to the main rx loop. */
> > + *skb_xdp_pass = skb;
> > + }
> > +
> > +refill:
> > + new_data = vmxnet3_pp_get_buff(rq->page_pool, &new_dma_addr,
> > + GFP_KERNEL);
>
> This code is being run in the softirq context, you can't use
> %GFP_KERNEL here, only %GFP_ATOMIC.
good catch, thanks.
>
> > + if (!new_data) {
> > + rq->stats.rx_buf_alloc_failure++;
> > + return XDP_DROP;
> > + }
> > + rbi->pp_page = virt_to_head_page(new_data);
> > + rbi->dma_addr = new_dma_addr;
> > + rxd->addr = cpu_to_le64(rbi->dma_addr);
> > + rxd->len = rbi->len;
> > + return act;
> > +}
> > diff --git a/drivers/net/vmxnet3/vmxnet3_xdp.h b/drivers/net/vmxnet3/vmxnet3_xdp.h
> > new file mode 100644
> > index 000000000000..cac4c9b82c93
> > --- /dev/null
> > +++ b/drivers/net/vmxnet3/vmxnet3_xdp.h
> > @@ -0,0 +1,39 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later
> > + *
> > + * Linux driver for VMware's vmxnet3 ethernet NIC.
> > + * Copyright (C) 2008-2023, VMware, Inc. All Rights Reserved.
> > + * Maintained by: pv-drivers@...are.com
> > + *
> > + */
> > +
> > +#ifndef _VMXNET3_XDP_H
> > +#define _VMXNET3_XDP_H
> > +
> > +#include <linux/filter.h>
> > +#include <linux/bpf_trace.h>
> > +#include <linux/netlink.h>
> > +#include <net/page_pool.h>
> > +#include <net/xdp.h>
> > +
> > +#include "vmxnet3_int.h"
> > +
> > +#define VMXNET3_XDP_ROOM (SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) + \
> > + XDP_PACKET_HEADROOM)
>
> Please aling to the opening braces.
OK
>
> > +#define VMXNET3_XDP_MAX_MTU (PAGE_SIZE - VMXNET3_XDP_ROOM)
> > +
> > +int vmxnet3_xdp(struct net_device *netdev, struct netdev_bpf *bpf);
> > +void vmxnet3_unregister_xdp_rxq(struct vmxnet3_rx_queue *rq);
> > +int vmxnet3_register_xdp_rxq(struct vmxnet3_rx_queue *rq,
> > + struct vmxnet3_adapter *adapter);
> > +int vmxnet3_xdp_headroom(struct vmxnet3_adapter *adapter);
> > +int vmxnet3_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
> > + u32 flags);
> > +int vmxnet3_process_xdp(struct vmxnet3_adapter *adapter,
> > + struct vmxnet3_rx_queue *rq,
> > + struct Vmxnet3_RxCompDesc *rcd,
> > + struct vmxnet3_rx_buf_info *rbi,
> > + struct Vmxnet3_RxDesc *rxd,
> > + struct sk_buff **skb_xdp_pass);
> > +void *vmxnet3_pp_get_buff(struct page_pool *pp, dma_addr_t *dma_addr,
> > + gfp_t gfp_mask);
> > +#endif
> > --
> > 2.25.1
>
> [0] https://elixir.bootlin.com/linux/v6.2-rc2/source/include/linux/filter.h#L992
>
> Thanks,
> Olek
Thanks a lot for such a detailed review!
I'm working on it and will send next version.
William
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