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).

Reviewed-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 12 insertions, 10 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;
 }