> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf Of
> Alexander Lobakin
> Sent: Tuesday, April 15, 2025 7:28 PM
> To: [email protected]
> Cc: Lobakin, Aleksander <[email protected]>; Kubiak, Michal
> <[email protected]>; Fijalkowski, Maciej
> <[email protected]>; Nguyen, Anthony L
> <[email protected]>; Kitszel, Przemyslaw
> <[email protected]>; Andrew Lunn <[email protected]>;
> David S. Miller <[email protected]>; Dumazet, Eric
> <[email protected]>; Jakub Kicinski <[email protected]>; Paolo Abeni
> <[email protected]>; Alexei Starovoitov <[email protected]>; Daniel
> Borkmann <[email protected]>; Jesper Dangaard Brouer
> <[email protected]>; John Fastabend <[email protected]>; Simon
> Horman <[email protected]>; [email protected]; [email protected];
> [email protected]; Mina Almasry <[email protected]>
> Subject: [Intel-wired-lan] [PATCH iwl-next 01/16] libeth: convert to netmem
>
> Back when the libeth Rx core was initially written, devmem was a draft and
> netmem_ref didn't exist in the mainline. Now that it's here, make libeth MP-
> agnostic before introducing any new code or any new library users.
> When it's known that the created PP/FQ is for header buffers, use faster
> "unsafe" underscored netmem <--> virt accessors as netmem_is_net_iov() is
> always false in that case, but consumes some cycles (bit test + true branch).
> Misc: replace explicit EXPORT_SYMBOL_NS_GPL("NS") with
> DEFAULT_SYMBOL_NAMESPACE.
>
> Reviewed-by: Mina Almasry <[email protected]>
> Signed-off-by: Alexander Lobakin <[email protected]>
> ---
> include/net/libeth/rx.h | 22 +++++++------
> drivers/net/ethernet/intel/iavf/iavf_txrx.c | 14 ++++----
> .../ethernet/intel/idpf/idpf_singleq_txrx.c | 2 +-
> drivers/net/ethernet/intel/idpf/idpf_txrx.c | 33 +++++++++++--------
> drivers/net/ethernet/intel/libeth/rx.c | 20 ++++++-----
> 5 files changed, 51 insertions(+), 40 deletions(-)
>
> diff --git a/include/net/libeth/rx.h b/include/net/libeth/rx.h index
> ab05024be518..7d5dc58984b1 100644
> --- a/include/net/libeth/rx.h
> +++ b/include/net/libeth/rx.h
> @@ -1,5 +1,5 @@
> /* SPDX-License-Identifier: GPL-2.0-only */
> -/* Copyright (C) 2024 Intel Corporation */
> +/* Copyright (C) 2024-2025 Intel Corporation */
>
> #ifndef __LIBETH_RX_H
> #define __LIBETH_RX_H
> @@ -31,7 +31,7 @@
>
> /**
> * struct libeth_fqe - structure representing an Rx buffer (fill queue
> element)
> - * @page: page holding the buffer
> + * @netmem: network memory reference holding the buffer
> * @offset: offset from the page start (to the headroom)
> * @truesize: total space occupied by the buffer (w/ headroom and tailroom)
> *
> @@ -40,7 +40,7 @@
> * former, @offset is always 0 and @truesize is always ```PAGE_SIZE```.
> */
> struct libeth_fqe {
> - struct page *page;
> + netmem_ref netmem;
> u32 offset;
> u32 truesize;
> } __aligned_largest;
> @@ -102,15 +102,16 @@ static inline dma_addr_t libeth_rx_alloc(const
> struct libeth_fq_fp *fq, u32 i)
> struct libeth_fqe *buf = &fq->fqes[i];
>
> buf->truesize = fq->truesize;
> - buf->page = page_pool_dev_alloc(fq->pp, &buf->offset, &buf-
> >truesize);
> - if (unlikely(!buf->page))
> + buf->netmem = page_pool_dev_alloc_netmem(fq->pp, &buf->offset,
> + &buf->truesize);
> + if (unlikely(!buf->netmem))
> return DMA_MAPPING_ERROR;
>
> - return page_pool_get_dma_addr(buf->page) + buf->offset +
> + return page_pool_get_dma_addr_netmem(buf->netmem) + buf-
> >offset +
> fq->pp->p.offset;
> }
>
> -void libeth_rx_recycle_slow(struct page *page);
> +void libeth_rx_recycle_slow(netmem_ref netmem);
>
> /**
> * libeth_rx_sync_for_cpu - synchronize or recycle buffer post DMA @@ -
> 126,18 +127,19 @@ void libeth_rx_recycle_slow(struct page *page); static
> inline bool libeth_rx_sync_for_cpu(const struct libeth_fqe *fqe,
> u32 len)
> {
> - struct page *page = fqe->page;
> + netmem_ref netmem = fqe->netmem;
>
> /* Very rare, but possible case. The most common reason:
> * the last fragment contained FCS only, which was then
> * stripped by the HW.
> */
> if (unlikely(!len)) {
> - libeth_rx_recycle_slow(page);
> + libeth_rx_recycle_slow(netmem);
> return false;
> }
>
> - page_pool_dma_sync_for_cpu(page->pp, page, fqe->offset, len);
> + page_pool_dma_sync_netmem_for_cpu(netmem_get_pp(netmem),
> netmem,
> + fqe->offset, len);
>
> return true;
> }
> diff --git a/drivers/net/ethernet/intel/iavf/iavf_txrx.c
> b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
> index 422312b8b54a..35d353d38129 100644
> --- a/drivers/net/ethernet/intel/iavf/iavf_txrx.c
> +++ b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
> @@ -723,7 +723,7 @@ static void iavf_clean_rx_ring(struct iavf_ring
> *rx_ring)
> for (u32 i = rx_ring->next_to_clean; i != rx_ring->next_to_use; ) {
> const struct libeth_fqe *rx_fqes = &rx_ring->rx_fqes[i];
>
> - page_pool_put_full_page(rx_ring->pp, rx_fqes->page, false);
> + libeth_rx_recycle_slow(rx_fqes->netmem);
>
> if (unlikely(++i == rx_ring->count))
> i = 0;
> @@ -1197,10 +1197,11 @@ static void iavf_add_rx_frag(struct sk_buff *skb,
> const struct libeth_fqe *rx_buffer,
> unsigned int size)
> {
> - u32 hr = rx_buffer->page->pp->p.offset;
> + u32 hr = netmem_get_pp(rx_buffer->netmem)->p.offset;
>
> - skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page,
> - rx_buffer->offset + hr, size, rx_buffer->truesize);
> + skb_add_rx_frag_netmem(skb, skb_shinfo(skb)->nr_frags,
> + rx_buffer->netmem, rx_buffer->offset + hr,
> + size, rx_buffer->truesize);
> }
>
> /**
> @@ -1214,12 +1215,13 @@ static void iavf_add_rx_frag(struct sk_buff *skb,
> static struct sk_buff *iavf_build_skb(const struct libeth_fqe *rx_buffer,
> unsigned int size)
> {
> - u32 hr = rx_buffer->page->pp->p.offset;
> + struct page *buf_page = __netmem_to_page(rx_buffer->netmem);
> + u32 hr = buf_page->pp->p.offset;
> struct sk_buff *skb;
> void *va;
>
> /* prefetch first cache line of first page */
> - va = page_address(rx_buffer->page) + rx_buffer->offset;
> + va = page_address(buf_page) + rx_buffer->offset;
> net_prefetch(va + hr);
>
> /* build an skb around the page buffer */ diff --git
> a/drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c
> b/drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c
> index eae1b6f474e6..aeb2ca5f5a0a 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_singleq_txrx.c
> @@ -1009,7 +1009,7 @@ static int idpf_rx_singleq_clean(struct
> idpf_rx_queue *rx_q, int budget)
> break;
>
> skip_data:
> - rx_buf->page = NULL;
> + rx_buf->netmem = 0;
>
> IDPF_SINGLEQ_BUMP_RING_IDX(rx_q, ntc);
> cleaned_count++;
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
> b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
> index bdf52cef3891..6254806c2072 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
> @@ -382,12 +382,12 @@ static int idpf_tx_desc_alloc_all(struct idpf_vport
> *vport)
> */
> static void idpf_rx_page_rel(struct libeth_fqe *rx_buf) {
> - if (unlikely(!rx_buf->page))
> + if (unlikely(!rx_buf->netmem))
> return;
>
> - page_pool_put_full_page(rx_buf->page->pp, rx_buf->page, false);
> + libeth_rx_recycle_slow(rx_buf->netmem);
>
> - rx_buf->page = NULL;
> + rx_buf->netmem = 0;
> rx_buf->offset = 0;
> }
>
> @@ -3096,10 +3096,10 @@ idpf_rx_process_skb_fields(struct
> idpf_rx_queue *rxq, struct sk_buff *skb, void idpf_rx_add_frag(struct
> idpf_rx_buf *rx_buf, struct sk_buff *skb,
> unsigned int size)
> {
> - u32 hr = rx_buf->page->pp->p.offset;
> + u32 hr = netmem_get_pp(rx_buf->netmem)->p.offset;
>
> - skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buf->page,
> - rx_buf->offset + hr, size, rx_buf->truesize);
> + skb_add_rx_frag_netmem(skb, skb_shinfo(skb)->nr_frags, rx_buf-
> >netmem,
> + rx_buf->offset + hr, size, rx_buf->truesize);
> }
>
> /**
> @@ -3122,16 +3122,20 @@ static u32 idpf_rx_hsplit_wa(const struct
> libeth_fqe *hdr,
> struct libeth_fqe *buf, u32 data_len) {
> u32 copy = data_len <= L1_CACHE_BYTES ? data_len : ETH_HLEN;
> + struct page *hdr_page, *buf_page;
> const void *src;
> void *dst;
>
> - if (!libeth_rx_sync_for_cpu(buf, copy))
> + if (unlikely(netmem_is_net_iov(buf->netmem)) ||
> + !libeth_rx_sync_for_cpu(buf, copy))
> return 0;
>
> - dst = page_address(hdr->page) + hdr->offset + hdr->page->pp-
> >p.offset;
> - src = page_address(buf->page) + buf->offset + buf->page->pp-
> >p.offset;
> - memcpy(dst, src, LARGEST_ALIGN(copy));
> + hdr_page = __netmem_to_page(hdr->netmem);
> + buf_page = __netmem_to_page(buf->netmem);
> + dst = page_address(hdr_page) + hdr->offset + hdr_page->pp-
> >p.offset;
> + src = page_address(buf_page) + buf->offset + buf_page->pp->p.offset;
>
> + memcpy(dst, src, LARGEST_ALIGN(copy));
Can you avoid 'unstable' API __netmem_to_page() usage? For example:
- dst = page_address(hdr->page) + hdr->offset + hdr->page->pp->p.offset;
- src = page_address(buf->page) + buf->offset + buf->page->pp->p.offset;
- memcpy(dst, src, LARGEST_ALIGN(copy));
+ dst = netmem_address(hdr->netmem) + hdr->offset;
+ src = netmem_address(buf->netmem) + buf->offset;
+ memcpy(dst, src, LARGEST_ALIGN(copy));
> buf->offset += copy;
>
> return copy;
> @@ -3147,11 +3151,12 @@ static u32 idpf_rx_hsplit_wa(const struct
> libeth_fqe *hdr,
> */
> struct sk_buff *idpf_rx_build_skb(const struct libeth_fqe *buf, u32 size) {
> - u32 hr = buf->page->pp->p.offset;
> + struct page *buf_page = __netmem_to_page(buf->netmem);
> + u32 hr = buf_page->pp->p.offset;
> struct sk_buff *skb;
> void *va;
>
> - va = page_address(buf->page) + buf->offset;
> + va = page_address(buf_page) + buf->offset;
> prefetch(va + hr);
>
> skb = napi_build_skb(va, buf->truesize); @@ -3302,7 +3307,7 @@
> static int idpf_rx_splitq_clean(struct idpf_rx_queue *rxq, int budget)
> u64_stats_update_end(&rxq->stats_sync);
> }
>
> - hdr->page = NULL;
> + hdr->netmem = 0;
>
> payload:
> if (!libeth_rx_sync_for_cpu(rx_buf, pkt_len)) @@ -3318,7
> +3323,7 @@ static int idpf_rx_splitq_clean(struct idpf_rx_queue *rxq, int
> budget)
> break;
>
> skip_data:
> - rx_buf->page = NULL;
> + rx_buf->netmem = 0;
>
> idpf_rx_post_buf_refill(refillq, buf_id);
> IDPF_RX_BUMP_NTC(rxq, ntc);
> diff --git a/drivers/net/ethernet/intel/libeth/rx.c
> b/drivers/net/ethernet/intel/libeth/rx.c
> index 66d1d23b8ad2..aa5d878181f7 100644
> --- a/drivers/net/ethernet/intel/libeth/rx.c
> +++ b/drivers/net/ethernet/intel/libeth/rx.c
> @@ -1,5 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0-only
> -/* Copyright (C) 2024 Intel Corporation */
> +/* Copyright (C) 2024-2025 Intel Corporation */
> +
> +#define DEFAULT_SYMBOL_NAMESPACE "LIBETH"
>
> #include <net/libeth/rx.h>
>
> @@ -186,7 +188,7 @@ int libeth_rx_fq_create(struct libeth_fq *fq, struct
> napi_struct *napi)
>
> return -ENOMEM;
> }
> -EXPORT_SYMBOL_NS_GPL(libeth_rx_fq_create, "LIBETH");
> +EXPORT_SYMBOL_GPL(libeth_rx_fq_create);
>
> /**
> * libeth_rx_fq_destroy - destroy a &page_pool created by libeth @@ -197,19
> +199,19 @@ void libeth_rx_fq_destroy(struct libeth_fq *fq)
> kvfree(fq->fqes);
> page_pool_destroy(fq->pp);
> }
> -EXPORT_SYMBOL_NS_GPL(libeth_rx_fq_destroy, "LIBETH");
> +EXPORT_SYMBOL_GPL(libeth_rx_fq_destroy);
>
> /**
> - * libeth_rx_recycle_slow - recycle a libeth page from the NAPI context
> - * @page: page to recycle
> + * libeth_rx_recycle_slow - recycle libeth netmem
> + * @netmem: network memory to recycle
> *
> * To be used on exceptions or rare cases not requiring fast inline
> recycling.
> */
> -void libeth_rx_recycle_slow(struct page *page)
> +void __cold libeth_rx_recycle_slow(netmem_ref netmem)
> {
> - page_pool_recycle_direct(page->pp, page);
> + page_pool_put_full_netmem(netmem_get_pp(netmem), netmem,
> false);
> }
> -EXPORT_SYMBOL_NS_GPL(libeth_rx_recycle_slow, "LIBETH");
> +EXPORT_SYMBOL_GPL(libeth_rx_recycle_slow);
>
> /* Converting abstract packet type numbers into a software structure with
> * the packet parameters to do O(1) lookup on Rx.
> @@ -251,7 +253,7 @@ void libeth_rx_pt_gen_hash_type(struct libeth_rx_pt
> *pt)
> pt->hash_type |= libeth_rx_pt_xdp_iprot[pt->inner_prot];
> pt->hash_type |= libeth_rx_pt_xdp_pl[pt->payload_layer];
> }
> -EXPORT_SYMBOL_NS_GPL(libeth_rx_pt_gen_hash_type, "LIBETH");
> +EXPORT_SYMBOL_GPL(libeth_rx_pt_gen_hash_type);
>
> /* Module */
>
> --
> 2.49.0
