net: mvneta: simplify mvneta_swbm_add_rx_fragment management

Relying on xdp frags bit, remove skb_shared_info structure
allocated on the stack in mvneta_rx_swbm routine and simplify
mvneta_swbm_add_rx_fragment accessing skb_shared_info in the
xdp_buff structure directly. There is no performance penalty in
this approach since mvneta_swbm_add_rx_fragment is run just
for xdp frags use-case.

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/45f050c094ccffce49d6bc5112939ed35250ba90.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index a3e74a4..bc70292 100644 (file)
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2060,9 +2060,9 @@ 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,
-                   int sync_len)
+                   struct xdp_buff *xdp, int sync_len)
 {
+       struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
        int i;
 
        if (likely(!xdp_buff_has_frags(xdp)))
@@ -2210,7 +2210,6 @@ 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);
        unsigned int len, data_len, sync;
        u32 ret, act;
 
@@ -2231,7 +2230,7 @@ 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, sync);
                        ret = MVNETA_XDP_DROPPED;
                } else {
                        ret = MVNETA_XDP_REDIR;
@@ -2242,7 +2241,7 @@ 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, sync);
                break;
        default:
                bpf_warn_invalid_xdp_action(pp->dev, prog, act);
@@ -2251,7 +2250,7 @@ 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, sync);
                ret = MVNETA_XDP_DROPPED;
                stats->xdp_drop++;
                break;
@@ -2303,9 +2302,9 @@ 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;
@@ -2323,8 +2322,11 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
                                len, dma_dir);
        rx_desc->buf_phys_addr = 0;
 
-       if (data_len > 0 && xdp_sinfo->nr_frags < MAX_SKB_FRAGS) {
-               skb_frag_t *frag = &xdp_sinfo->frags[xdp_sinfo->nr_frags++];
+       if (!xdp_buff_has_frags(xdp))
+               sinfo->nr_frags = 0;
+
+       if (data_len > 0 && sinfo->nr_frags < MAX_SKB_FRAGS) {
+               skb_frag_t *frag = &sinfo->frags[sinfo->nr_frags++];
 
                skb_frag_off_set(frag, pp->rx_offset_correction);
                skb_frag_size_set(frag, data_len);
@@ -2335,16 +2337,6 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
        } else {
                page_pool_put_full_page(rxq->page_pool, page, true);
        }
-
-       /* 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));
-       }
        *size -= len;
 }
 
@@ -2392,7 +2384,6 @@ 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;
@@ -2401,8 +2392,6 @@ 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;
-
        /* Get number of received packets */
        rx_todo = mvneta_rxq_busy_desc_num_get(pp, rxq);
 
@@ -2444,7 +2433,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
                        }
 
                        mvneta_swbm_add_rx_fragment(pp, rx_desc, rxq, &xdp_buf,
-                                                   &size, &sinfo, page);
+                                                   &size, page);
                } /* Middle or Last descriptor */
 
                if (!(rx_status & MVNETA_RXD_LAST_DESC))
@@ -2452,7 +2441,7 @@ 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, -1);
                        goto next;
                }
 
@@ -2464,7 +2453,7 @@ 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, -1);
 
                        u64_stats_update_begin(&stats->syncp);
                        stats->es.skb_alloc_error++;
@@ -2481,11 +2470,10 @@ 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;
        }
 
        if (xdp_buf.data_hard_start)
-               mvneta_xdp_put_buff(pp, rxq, &xdp_buf, &sinfo, -1);
+               mvneta_xdp_put_buff(pp, rxq, &xdp_buf, -1);
 
        if (ps.xdp_redirect)
                xdp_do_flush_map();