net: mvneta: alloc skb_shared_info on the mvneta_rx_swbm stack

Build skb_shared_info on mvneta_rx_swbm stack and sync it to xdp_buff
skb_shared_info area only on the last fragment. Leftover cache miss in
mvneta_swbm_rx_frame will be addressed introducing mb bit in
xdp_buff/xdp_frame struct

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 17c446b..b40804e 100644 (file)
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2278,9 +2278,9 @@ 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 page *page)
 {
-       struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
        struct net_device *dev = pp->dev;
        enum dma_data_direction dma_dir;
        int data_len, len;
@@ -2298,13 +2298,22 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
                                len, dma_dir);
        rx_desc->buf_phys_addr = 0;
 
-       if (data_len > 0 && sinfo->nr_frags < MAX_SKB_FRAGS) {
-               skb_frag_t *frag = &sinfo->frags[sinfo->nr_frags];
+       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);
-               sinfo->nr_frags++;
+
+               /* last fragment */
+               if (len == *size) {
+                       struct skb_shared_info *sinfo;
+
+                       sinfo = xdp_get_shared_info_from_buff(xdp);
+                       sinfo->nr_frags = xdp_sinfo->nr_frags;
+                       memcpy(sinfo->frags, xdp_sinfo->frags,
+                              sinfo->nr_frags * sizeof(skb_frag_t));
+               }
        } else {
                page_pool_put_full_page(rxq->page_pool, page, true);
        }
@@ -2348,6 +2357,7 @@ 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 mvneta_stats ps = {};
        struct bpf_prog *xdp_prog;
        u32 desc_status, frame_sz;
@@ -2357,6 +2367,8 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
        xdp_buf.frame_sz = PAGE_SIZE;
        xdp_buf.rxq = &rxq->xdp_rxq;
 
+       sinfo.nr_frags = 0;
+
        /* Get number of received packets */
        rx_todo = mvneta_rxq_busy_desc_num_get(pp, rxq);
 
@@ -2395,11 +2407,11 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
                                rx_desc->buf_phys_addr = 0;
                                page_pool_put_full_page(rxq->page_pool, page,
                                                        true);
-                               continue;
+                               goto next;
                        }
 
                        mvneta_swbm_add_rx_fragment(pp, rx_desc, rxq, &xdp_buf,
-                                                   &size, page);
+                                                   &size, &sinfo, page);
                } /* Middle or Last descriptor */
 
                if (!(rx_status & MVNETA_RXD_LAST_DESC))
@@ -2407,10 +2419,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
                        continue;
 
                if (size) {
-                       struct skb_shared_info *sinfo;
-
-                       sinfo = xdp_get_shared_info_from_buff(&xdp_buf);
-                       mvneta_xdp_put_buff(pp, rxq, &xdp_buf, sinfo, -1);
+                       mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &sinfo, -1);
                        goto next;
                }
 
@@ -2421,10 +2430,8 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
                skb = mvneta_swbm_build_skb(pp, rxq, &xdp_buf, desc_status);
                if (IS_ERR(skb)) {
                        struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
-                       struct skb_shared_info *sinfo;
 
-                       sinfo = xdp_get_shared_info_from_buff(&xdp_buf);
-                       mvneta_xdp_put_buff(pp, rxq, &xdp_buf, sinfo, -1);
+                       mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &sinfo, -1);
 
                        u64_stats_update_begin(&stats->syncp);
                        stats->es.skb_alloc_error++;
@@ -2441,15 +2448,12 @@ 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;
        }
        rcu_read_unlock();
 
-       if (xdp_buf.data_hard_start) {
-               struct skb_shared_info *sinfo;
-
-               sinfo = xdp_get_shared_info_from_buff(&xdp_buf);
-               mvneta_xdp_put_buff(pp, rxq, &xdp_buf, sinfo, -1);
-       }
+       if (xdp_buf.data_hard_start)
+               mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &sinfo, -1);
 
        if (ps.xdp_redirect)
                xdp_do_flush_map();