[Intel-wired-lan] [PATCH net-next 02/16] libeth: support native XDP and register memory model

[Alexander Lobakin]

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.loba...@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 7d5dc58984b1..5d991404845e 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 aa5d878181f7..c0be9cb043a1 100644
--- a/drivers/net/ethernet/intel/libeth/rx.c
+++ b/drivers/net/ethernet/intel/libeth/rx.c
@@ -70,7 +70,7 @@ 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);
 
@@ -157,11 +157,12 @@ 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);
@@ -175,18 +176,26 @@ 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_GPL(libeth_rx_fq_create);
 
@@ -196,6 +205,7 @@ EXPORT_SYMBOL_GPL(libeth_rx_fq_create);
  */
 void libeth_rx_fq_destroy(struct libeth_fq *fq)
 {
+       xdp_unreg_page_pool(fq->pp);
        kvfree(fq->fqes);
        page_pool_destroy(fq->pp);
 }
-- 
2.48.1