[PATCH net-next v2 17/18] libeth: support native XDP and register memory model

Alexander Lobakin
2024-10-15T14:55:24Z

Expand libeth's Page Pool functionality by adding native XDP support.
This means picking the appropriate headroom and DMA direction.
Also, register all the created &page_pools as XDP memory models.
A driver then can call xdp_rxq_info_attach_page_pool() when registering
its RxQ info.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
include/net/libeth/rx.h | 6 +++++-
drivers/net/ethernet/intel/libeth/rx.c | 20 +++++++++++++++-----
2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/include/net/libeth/rx.h b/include/net/libeth/rx.h
index 43574bd6612f..148be5cd822e 100644
--- a/include/net/libeth/rx.h
+++ b/include/net/libeth/rx.h
@@ -13,8 +13,10 @@

/* Space reserved in front of each frame */
#define LIBETH_SKB_HEADROOM (NET_SKB_PAD + NET_IP_ALIGN)
+#define LIBETH_XDP_HEADROOM (ALIGN(XDP_PACKET_HEADROOM, NET_SKB_PAD) + \
+ NET_IP_ALIGN)
/* Maximum headroom for worst-case calculations */
-#define LIBETH_MAX_HEADROOM LIBETH_SKB_HEADROOM
+#define LIBETH_MAX_HEADROOM LIBETH_XDP_HEADROOM
/* Link layer / L2 overhead: Ethernet, 2 VLAN tags (C + S), FCS */
#define LIBETH_RX_LL_LEN (ETH_HLEN + 2 * VLAN_HLEN + ETH_FCS_LEN)
/* Maximum supported L2-L4 header length */
@@ -66,6 +68,7 @@ enum libeth_fqe_type {
* @count: number of descriptors/buffers the queue has
* @type: type of the buffers this queue has
* @hsplit: flag whether header split is enabled
+ * @xdp: flag indicating whether XDP is enabled
* @buf_len: HW-writeable length per each buffer
* @nid: ID of the closest NUMA node with memory
*/
@@ -81,6 +84,7 @@ struct libeth_fq {
/* Cold fields */
enum libeth_fqe_type type:2;
bool hsplit:1;
+ bool xdp:1;

u32 buf_len;
int nid;
diff --git a/drivers/net/ethernet/intel/libeth/rx.c b/drivers/net/ethernet/intel/libeth/rx.c
index f20926669318..616426a2e363 100644
--- a/drivers/net/ethernet/intel/libeth/rx.c
+++ b/drivers/net/ethernet/intel/libeth/rx.c
@@ -68,7 +68,7 @@ static u32 libeth_rx_hw_len_truesize(const struct page_pool_params *pp,
static bool libeth_rx_page_pool_params(struct libeth_fq *fq,
struct page_pool_params *pp)
{
- pp->offset = LIBETH_SKB_HEADROOM;
+ pp->offset = fq->xdp ? LIBETH_XDP_HEADROOM : LIBETH_SKB_HEADROOM;
/* HW-writeable / syncable length per one page */
pp->max_len = LIBETH_RX_PAGE_LEN(pp->offset);

@@ -155,11 +155,12 @@ int libeth_rx_fq_create(struct libeth_fq *fq, struct napi_struct *napi)
.dev = napi->dev->dev.parent,
.netdev = napi->dev,
.napi = napi,
- .dma_dir = DMA_FROM_DEVICE,
};
struct libeth_fqe *fqes;
struct page_pool *pool;
- bool ret;
+ int ret;
+
+ pp.dma_dir = fq->xdp ? DMA_BIDIRECTIONAL : DMA_FROM_DEVICE;

if (!fq->hsplit)
ret = libeth_rx_page_pool_params(fq, &pp);
@@ -173,18 +174,26 @@ int libeth_rx_fq_create(struct libeth_fq *fq, struct napi_struct *napi)
return PTR_ERR(pool);

fqes = kvcalloc_node(fq->count, sizeof(*fqes), GFP_KERNEL, fq->nid);
- if (!fqes)
+ if (!fqes) {
+ ret = -ENOMEM;
goto err_buf;
+ }
+
+ ret = xdp_reg_page_pool(pool);
+ if (ret)
+ goto err_mem;

fq->fqes = fqes;
fq->pp = pool;

return 0;

+err_mem:
+ kvfree(fqes);
err_buf:
page_pool_destroy(pool);

- return -ENOMEM;
+ return ret;
}
EXPORT_SYMBOL_NS_GPL(libeth_rx_fq_create, LIBETH);

@@ -194,6 +203,7 @@ EXPORT_SYMBOL_NS_GPL(libeth_rx_fq_create, LIBETH);
*/
void libeth_rx_fq_destroy(struct libeth_fq *fq)
{
+ xdp_unreg_page_pool(fq->pp);
kvfree(fq->fqes);
page_pool_destroy(fq->pp);
}
--
2.46.2