Introduce xdp_shared_info data structure to contain info about
"non-linear" xdp frame. xdp_shared_info will alias skb_shared_info
allowing to keep most of the frags in the same cache-line.
Introduce some xdp_shared_info helpers aligned to skb_frag* ones

Signed-off-by: Lorenzo Bianconi <lore...@kernel.org>
---
 drivers/net/ethernet/marvell/mvneta.c | 62 +++++++++++++++------------
 include/net/xdp.h                     | 55 ++++++++++++++++++++++--
 2 files changed, 85 insertions(+), 32 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c 
b/drivers/net/ethernet/marvell/mvneta.c
index 6290bfb6494e..ed986ffff96b 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2033,14 +2033,17 @@ int mvneta_rx_refill_queue(struct mvneta_port *pp, 
struct mvneta_rx_queue *rxq)
 
 static void
 mvneta_xdp_put_buff(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
-                   struct xdp_buff *xdp, struct skb_shared_info *sinfo,
+                   struct xdp_buff *xdp, struct xdp_shared_info *xdp_sinfo,
                    int sync_len)
 {
        int i;
 
-       for (i = 0; i < sinfo->nr_frags; i++)
+       for (i = 0; i < xdp_sinfo->nr_frags; i++) {
+               skb_frag_t *frag = &xdp_sinfo->frags[i];
+
                page_pool_put_full_page(rxq->page_pool,
-                                       skb_frag_page(&sinfo->frags[i]), true);
+                                       xdp_get_frag_page(frag), true);
+       }
        page_pool_put_page(rxq->page_pool, virt_to_head_page(xdp->data),
                           sync_len, true);
 }
@@ -2179,7 +2182,7 @@ mvneta_run_xdp(struct mvneta_port *pp, struct 
mvneta_rx_queue *rxq,
               struct bpf_prog *prog, struct xdp_buff *xdp,
               u32 frame_sz, struct mvneta_stats *stats)
 {
-       struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
+       struct xdp_shared_info *xdp_sinfo = xdp_get_shared_info_from_buff(xdp);
        unsigned int len, data_len, sync;
        u32 ret, act;
 
@@ -2200,7 +2203,7 @@ mvneta_run_xdp(struct mvneta_port *pp, struct 
mvneta_rx_queue *rxq,
 
                err = xdp_do_redirect(pp->dev, xdp, prog);
                if (unlikely(err)) {
-                       mvneta_xdp_put_buff(pp, rxq, xdp, sinfo, sync);
+                       mvneta_xdp_put_buff(pp, rxq, xdp, xdp_sinfo, sync);
                        ret = MVNETA_XDP_DROPPED;
                } else {
                        ret = MVNETA_XDP_REDIR;
@@ -2211,7 +2214,7 @@ mvneta_run_xdp(struct mvneta_port *pp, struct 
mvneta_rx_queue *rxq,
        case XDP_TX:
                ret = mvneta_xdp_xmit_back(pp, xdp);
                if (ret != MVNETA_XDP_TX)
-                       mvneta_xdp_put_buff(pp, rxq, xdp, sinfo, sync);
+                       mvneta_xdp_put_buff(pp, rxq, xdp, xdp_sinfo, sync);
                break;
        default:
                bpf_warn_invalid_xdp_action(act);
@@ -2220,7 +2223,7 @@ mvneta_run_xdp(struct mvneta_port *pp, struct 
mvneta_rx_queue *rxq,
                trace_xdp_exception(pp->dev, prog, act);
                fallthrough;
        case XDP_DROP:
-               mvneta_xdp_put_buff(pp, rxq, xdp, sinfo, sync);
+               mvneta_xdp_put_buff(pp, rxq, xdp, xdp_sinfo, sync);
                ret = MVNETA_XDP_DROPPED;
                stats->xdp_drop++;
                break;
@@ -2241,9 +2244,9 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
 {
        unsigned char *data = page_address(page);
        int data_len = -MVNETA_MH_SIZE, len;
+       struct xdp_shared_info *xdp_sinfo;
        struct net_device *dev = pp->dev;
        enum dma_data_direction dma_dir;
-       struct skb_shared_info *sinfo;
 
        if (*size > MVNETA_MAX_RX_BUF_SIZE) {
                len = MVNETA_MAX_RX_BUF_SIZE;
@@ -2266,8 +2269,8 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
        xdp_prepare_buff(xdp, data, pp->rx_offset_correction + MVNETA_MH_SIZE,
                         data_len, false);
 
-       sinfo = xdp_get_shared_info_from_buff(xdp);
-       sinfo->nr_frags = 0;
+       xdp_sinfo = xdp_get_shared_info_from_buff(xdp);
+       xdp_sinfo->nr_frags = 0;
 }
 
 static void
@@ -2275,7 +2278,7 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
                            struct mvneta_rx_desc *rx_desc,
                            struct mvneta_rx_queue *rxq,
                            struct xdp_buff *xdp, int *size,
-                           struct skb_shared_info *xdp_sinfo,
+                           struct xdp_shared_info *xdp_sinfo,
                            struct page *page)
 {
        struct net_device *dev = pp->dev;
@@ -2298,13 +2301,13 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
        if (data_len > 0 && xdp_sinfo->nr_frags < MAX_SKB_FRAGS) {
                skb_frag_t *frag = &xdp_sinfo->frags[xdp_sinfo->nr_frags++];
 
-               skb_frag_off_set(frag, pp->rx_offset_correction);
-               skb_frag_size_set(frag, data_len);
-               __skb_frag_set_page(frag, page);
+               xdp_set_frag_offset(frag, pp->rx_offset_correction);
+               xdp_set_frag_size(frag, data_len);
+               xdp_set_frag_page(frag, page);
 
                /* last fragment */
                if (len == *size) {
-                       struct skb_shared_info *sinfo;
+                       struct xdp_shared_info *sinfo;
 
                        sinfo = xdp_get_shared_info_from_buff(xdp);
                        sinfo->nr_frags = xdp_sinfo->nr_frags;
@@ -2321,10 +2324,13 @@ static struct sk_buff *
 mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
                      struct xdp_buff *xdp, u32 desc_status)
 {
-       struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
-       int i, num_frags = sinfo->nr_frags;
+       struct xdp_shared_info *xdp_sinfo = xdp_get_shared_info_from_buff(xdp);
+       int i, num_frags = xdp_sinfo->nr_frags;
+       skb_frag_t frag_list[MAX_SKB_FRAGS];
        struct sk_buff *skb;
 
+       memcpy(frag_list, xdp_sinfo->frags, sizeof(skb_frag_t) * num_frags);
+
        skb = build_skb(xdp->data_hard_start, PAGE_SIZE);
        if (!skb)
                return ERR_PTR(-ENOMEM);
@@ -2336,12 +2342,12 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct 
mvneta_rx_queue *rxq,
        mvneta_rx_csum(pp, desc_status, skb);
 
        for (i = 0; i < num_frags; i++) {
-               skb_frag_t *frag = &sinfo->frags[i];
+               struct page *page = xdp_get_frag_page(&frag_list[i]);
 
                skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
-                               skb_frag_page(frag), skb_frag_off(frag),
-                               skb_frag_size(frag), PAGE_SIZE);
-               page_pool_release_page(rxq->page_pool, skb_frag_page(frag));
+                               page, xdp_get_frag_offset(&frag_list[i]),
+                               xdp_get_frag_size(&frag_list[i]), PAGE_SIZE);
+               page_pool_release_page(rxq->page_pool, page);
        }
 
        return skb;
@@ -2354,7 +2360,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 {
        int rx_proc = 0, rx_todo, refill, size = 0;
        struct net_device *dev = pp->dev;
-       struct skb_shared_info sinfo;
+       struct xdp_shared_info xdp_sinfo;
        struct mvneta_stats ps = {};
        struct bpf_prog *xdp_prog;
        u32 desc_status, frame_sz;
@@ -2363,7 +2369,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
        xdp_init_buff(&xdp_buf, PAGE_SIZE, &rxq->xdp_rxq);
        xdp_buf.data_hard_start = NULL;
 
-       sinfo.nr_frags = 0;
+       xdp_sinfo.nr_frags = 0;
 
        /* Get number of received packets */
        rx_todo = mvneta_rxq_busy_desc_num_get(pp, rxq);
@@ -2407,7 +2413,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
                        }
 
                        mvneta_swbm_add_rx_fragment(pp, rx_desc, rxq, &xdp_buf,
-                                                   &size, &sinfo, page);
+                                                   &size, &xdp_sinfo, page);
                } /* Middle or Last descriptor */
 
                if (!(rx_status & MVNETA_RXD_LAST_DESC))
@@ -2415,7 +2421,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
                        continue;
 
                if (size) {
-                       mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &sinfo, -1);
+                       mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &xdp_sinfo, -1);
                        goto next;
                }
 
@@ -2427,7 +2433,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
                if (IS_ERR(skb)) {
                        struct mvneta_pcpu_stats *stats = 
this_cpu_ptr(pp->stats);
 
-                       mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &sinfo, -1);
+                       mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &xdp_sinfo, -1);
 
                        u64_stats_update_begin(&stats->syncp);
                        stats->es.skb_alloc_error++;
@@ -2444,12 +2450,12 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
                napi_gro_receive(napi, skb);
 next:
                xdp_buf.data_hard_start = NULL;
-               sinfo.nr_frags = 0;
+               xdp_sinfo.nr_frags = 0;
        }
        rcu_read_unlock();
 
        if (xdp_buf.data_hard_start)
-               mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &sinfo, -1);
+               mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &xdp_sinfo, -1);
 
        if (ps.xdp_redirect)
                xdp_do_flush_map();
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 945767813fdd..ca7c4fb30b4e 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -107,10 +107,54 @@ xdp_prepare_buff(struct xdp_buff *xdp, unsigned char 
*hard_start,
        ((xdp)->data_hard_start + (xdp)->frame_sz -     \
         SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
 
-static inline struct skb_shared_info *
+struct xdp_shared_info {
+       u16 nr_frags;
+       u16 data_length; /* paged area length */
+       skb_frag_t frags[MAX_SKB_FRAGS];
+};
+
+static inline struct xdp_shared_info *
 xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
 {
-       return (struct skb_shared_info *)xdp_data_hard_end(xdp);
+       BUILD_BUG_ON(sizeof(struct xdp_shared_info) >
+                    sizeof(struct skb_shared_info));
+       return (struct xdp_shared_info *)xdp_data_hard_end(xdp);
+}
+
+static inline struct page *xdp_get_frag_page(const skb_frag_t *frag)
+{
+       return frag->bv_page;
+}
+
+static inline unsigned int xdp_get_frag_offset(const skb_frag_t *frag)
+{
+       return frag->bv_offset;
+}
+
+static inline unsigned int xdp_get_frag_size(const skb_frag_t *frag)
+{
+       return frag->bv_len;
+}
+
+static inline void *xdp_get_frag_address(const skb_frag_t *frag)
+{
+       return page_address(xdp_get_frag_page(frag)) +
+              xdp_get_frag_offset(frag);
+}
+
+static inline void xdp_set_frag_page(skb_frag_t *frag, struct page *page)
+{
+       frag->bv_page = page;
+}
+
+static inline void xdp_set_frag_offset(skb_frag_t *frag, u32 offset)
+{
+       frag->bv_offset = offset;
+}
+
+static inline void xdp_set_frag_size(skb_frag_t *frag, u32 size)
+{
+       frag->bv_len = size;
 }
 
 struct xdp_frame {
@@ -140,12 +184,15 @@ static __always_inline void xdp_frame_bulk_init(struct 
xdp_frame_bulk *bq)
        bq->xa = NULL;
 }
 
-static inline struct skb_shared_info *
+static inline struct xdp_shared_info *
 xdp_get_shared_info_from_frame(struct xdp_frame *frame)
 {
        void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
 
-       return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
+       /* xdp_shared_info struct must be aligned to skb_shared_info
+        * area in buffer tailroom
+        */
+       return (struct xdp_shared_info *)(data_hard_start + frame->frame_sz -
                                SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
 }
 
-- 
2.29.2

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