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Message-ID: <20240104130016.47bc1071@kernel.org>
Date: Thu, 4 Jan 2024 13:00:16 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Shinas Rasheed <srasheed@...vell.com>
Cc: <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<hgani@...vell.com>, <vimleshk@...vell.com>, <sedara@...vell.com>,
<egallen@...hat.com>, <mschmidt@...hat.com>, <pabeni@...hat.com>,
<horms@...nel.org>, <wizhao@...hat.com>, <kheib@...hat.com>,
<konguyen@...hat.com>, Veerasenareddy Burru <vburru@...vell.com>, Satananda
Burla <sburla@...vell.com>, "David S. Miller" <davem@...emloft.net>, Eric
Dumazet <edumazet@...gle.com>
Subject: Re: [PATCH net-next v2 6/8] octeon_ep_vf: add Tx/Rx processing and
interrupt support
On Sat, 23 Dec 2023 05:39:58 -0800 Shinas Rasheed wrote:
> +static int octep_vf_napi_poll(struct napi_struct *napi, int budget)
> +{
> + struct octep_vf_ioq_vector *ioq_vector =
> + container_of(napi, struct octep_vf_ioq_vector, napi);
> + u32 tx_pending, rx_done;
> +
> + tx_pending = octep_vf_iq_process_completions(ioq_vector->iq, budget);
completions should use some static budget, say 256, the budget passed
in is for Rx.
> + rx_done = octep_vf_oq_process_rx(ioq_vector->oq, budget);
You should not call Rx processing if budget is 0 at all, please see
NAPI docs. Looks like the function may try to refill Rx buffers with
budget of 0.
> + /* need more polling if tx completion processing is still pending or
> + * processed at least 'budget' number of rx packets.
> + */
> + if (tx_pending || rx_done >= budget)
> + return budget;
> +
> + napi_complete(napi);
please use napi_complete_done().
> + octep_vf_enable_ioq_irq(ioq_vector->iq, ioq_vector->oq);
> + return rx_done;
> +}
> /**
> * octep_vf_start_xmit() - Enqueue packet to Octoen hardware Tx Queue.
> *
> @@ -184,6 +591,143 @@ static int octep_vf_stop(struct net_device *netdev)
> static netdev_tx_t octep_vf_start_xmit(struct sk_buff *skb,
> struct net_device *netdev)
> {
> [...]
> +dma_map_sg_err:
> + if (si > 0) {
> + dma_unmap_single(iq->dev, sglist[0].dma_ptr[0],
> + sglist[0].len[0], DMA_TO_DEVICE);
> + sglist[0].len[0] = 0;
> + }
> + while (si > 1) {
> + dma_unmap_page(iq->dev, sglist[si >> 2].dma_ptr[si & 3],
> + sglist[si >> 2].len[si & 3], DMA_TO_DEVICE);
> + sglist[si >> 2].len[si & 3] = 0;
> + si--;
> + }
> + tx_buffer->gather = 0;
> +dma_map_err:
if previous tx had xmit_more() you need to ring the doorbell here
> + dev_kfree_skb_any(skb);
> return NETDEV_TX_OK;
> }
> @@ -114,8 +158,8 @@ static int octep_vf_setup_oq(struct octep_vf_device *oct, int q_no)
> goto desc_dma_alloc_err;
> }
>
> - oq->buff_info = (struct octep_vf_rx_buffer *)
> - vzalloc(oq->max_count * OCTEP_VF_OQ_RECVBUF_SIZE);
> + oq->buff_info = vzalloc(oq->max_count * OCTEP_VF_OQ_RECVBUF_SIZE);
> +
bad fixup squash?
> if (unlikely(!oq->buff_info)) {
> dev_err(&oct->pdev->dev,
> "Failed to allocate buffer info for OQ-%d\n", q_no);
> + /* Swap the length field that is in Big-Endian to CPU */
> + buff_info->len = be64_to_cpu(resp_hw->length);
> + if (oct->fw_info.rx_ol_flags) {
> + /* Extended response header is immediately after
> + * response header (resp_hw)
> + */
> + resp_hw_ext = (struct octep_vf_oq_resp_hw_ext *)
> + (resp_hw + 1);
> + buff_info->len -= OCTEP_VF_OQ_RESP_HW_EXT_SIZE;
> + /* Packet Data is immediately after
> + * extended response header.
> + */
> + data_offset = OCTEP_VF_OQ_RESP_HW_SIZE +
> + OCTEP_VF_OQ_RESP_HW_EXT_SIZE;
> + rx_ol_flags = resp_hw_ext->rx_ol_flags;
> + } else {
> + /* Data is immediately after
> + * Hardware Rx response header.
> + */
> + data_offset = OCTEP_VF_OQ_RESP_HW_SIZE;
> + rx_ol_flags = 0;
> + }
> + rx_bytes += buff_info->len;
> +
> + if (buff_info->len <= oq->max_single_buffer_size) {
> + skb = build_skb((void *)resp_hw, PAGE_SIZE);
napi_build_skb() ?
> + skb_reserve(skb, data_offset);
> + skb_put(skb, buff_info->len);
> + read_idx++;
> + desc_used++;
> + if (read_idx == oq->max_count)
> + read_idx = 0;
> + } else {
> + struct skb_shared_info *shinfo;
> + u16 data_len;
> +
> + skb = build_skb((void *)resp_hw, PAGE_SIZE);
ditto
> + skb_reserve(skb, data_offset);
> + /* Head fragment includes response header(s);
> + * subsequent fragments contains only data.
> + */
> + skb_put(skb, oq->max_single_buffer_size);
> + read_idx++;
> + desc_used++;
> + if (read_idx == oq->max_count)
> + read_idx = 0;
> +
> + shinfo = skb_shinfo(skb);
> + data_len = buff_info->len - oq->max_single_buffer_size;
> + while (data_len) {
> + dma_unmap_page(oq->dev, oq->desc_ring[read_idx].buffer_ptr,
> + PAGE_SIZE, DMA_FROM_DEVICE);
> + buff_info = (struct octep_vf_rx_buffer *)
> + &oq->buff_info[read_idx];
> + if (data_len < oq->buffer_size) {
> + buff_info->len = data_len;
> + data_len = 0;
> + } else {
> + buff_info->len = oq->buffer_size;
> + data_len -= oq->buffer_size;
> + }
> +
> + skb_add_rx_frag(skb, shinfo->nr_frags,
> + buff_info->page, 0,
> + buff_info->len,
> + buff_info->len);
> + buff_info->page = NULL;
> + read_idx++;
> + desc_used++;
> + if (read_idx == oq->max_count)
> + read_idx = 0;
> + }
> + }
> +
> + skb->dev = oq->netdev;
> + skb->protocol = eth_type_trans(skb, skb->dev);
double space
> + if (feat & NETIF_F_RXCSUM &&
> + OCTEP_VF_RX_CSUM_VERIFIED(rx_ol_flags))
> + skb->ip_summed = CHECKSUM_UNNECESSARY;
> + else
> + skb->ip_summed = CHECKSUM_NONE;
> + napi_gro_receive(oq->napi, skb);
> + }
> +
> + oq->host_read_idx = read_idx;
> + oq->refill_count += desc_used;
> + oq->stats.packets += pkt;
> + oq->stats.bytes += rx_bytes;
> +
> + return pkt;
> +}
> +/**
> + * octep_vf_iq_process_completions() - Process Tx queue completions.
> + *
> + * @iq: Octeon Tx queue data structure.
> + * @budget: max number of completions to be processed in one invocation.
> + */
> +int octep_vf_iq_process_completions(struct octep_vf_iq *iq, u16 budget)
> +{
> [...]
> + netdev_tx_completed_queue(iq->netdev_q, compl_pkts, compl_bytes);
> +
> + if (unlikely(__netif_subqueue_stopped(iq->netdev, iq->q_no)) &&
> + (IQ_INSTR_SPACE(iq) >
> + OCTEP_VF_WAKE_QUEUE_THRESHOLD))
> + netif_wake_subqueue(iq->netdev, iq->q_no);
Please use helpers form net/netdev_queues.h
> @@ -195,8 +267,7 @@ static void octep_vf_free_iq(struct octep_vf_iq *iq)
>
> desc_ring_size = OCTEP_VF_IQ_DESC_SIZE * CFG_GET_IQ_NUM_DESC(oct->conf);
>
> - if (iq->buff_info)
> - vfree(iq->buff_info);
> + vfree(iq->buff_info);
This should be in a previous patch.
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