ionic: refactor skb building

The existing ionic_rx_frags() code is a bit of a mess and can
be cleaned up by unrolling the first frag/header setup from
the loop, then reworking the do-while-loop into a for-loop.  We
rename the function to a more descriptive ionic_rx_build_skb().
We also change a couple of related variable names for readability.

Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index d4fd052fc48a8a3d285f9572ac3a3d379395c057..269253d84ca7ed8527d804731ffe461021ee585f 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -185,7 +185,7 @@ static void ionic_rx_page_free(struct ionic_queue *q,
 }
 
 static bool ionic_rx_buf_recycle(struct ionic_queue *q,
-                                struct ionic_buf_info *buf_info, u32 used)
+                                struct ionic_buf_info *buf_info, u32 len)
 {
        u32 size;
 
@@ -197,7 +197,7 @@ static bool ionic_rx_buf_recycle(struct ionic_queue *q,
        if (page_to_nid(buf_info->page) != numa_mem_id())
                return false;
 
-       size = ALIGN(used, q->xdp_rxq_info ? IONIC_PAGE_SIZE : IONIC_PAGE_SPLIT_SZ);
+       size = ALIGN(len, q->xdp_rxq_info ? IONIC_PAGE_SIZE : IONIC_PAGE_SPLIT_SZ);
        buf_info->page_offset += size;
        if (buf_info->page_offset >= IONIC_PAGE_SIZE)
                return false;
@@ -207,17 +207,37 @@ static bool ionic_rx_buf_recycle(struct ionic_queue *q,
        return true;
 }
 
-static struct sk_buff *ionic_rx_frags(struct net_device *netdev,
-                                     struct ionic_queue *q,
-                                     struct ionic_rx_desc_info *desc_info,
-                                     unsigned int headroom,
-                                     unsigned int len,
-                                     unsigned int num_sg_elems,
-                                     bool synced)
+static void ionic_rx_add_skb_frag(struct ionic_queue *q,
+                                 struct sk_buff *skb,
+                                 struct ionic_buf_info *buf_info,
+                                 u32 off, u32 len,
+                                 bool synced)
+{
+       if (!synced)
+               dma_sync_single_range_for_cpu(q->dev, ionic_rx_buf_pa(buf_info),
+                                             off, len, DMA_FROM_DEVICE);
+
+       skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
+                       buf_info->page, buf_info->page_offset + off,
+                       len,
+                       IONIC_PAGE_SIZE);
+
+       if (!ionic_rx_buf_recycle(q, buf_info, len)) {
+               dma_unmap_page(q->dev, buf_info->dma_addr,
+                              IONIC_PAGE_SIZE, DMA_FROM_DEVICE);
+               buf_info->page = NULL;
+       }
+}
+
+static struct sk_buff *ionic_rx_build_skb(struct ionic_queue *q,
+                                         struct ionic_rx_desc_info *desc_info,
+                                         unsigned int headroom,
+                                         unsigned int len,
+                                         unsigned int num_sg_elems,
+                                         bool synced)
 {
        struct ionic_buf_info *buf_info;
        struct ionic_rx_stats *stats;
-       struct device *dev = q->dev;
        struct sk_buff *skb;
        unsigned int i;
        u16 frag_len;
@@ -225,54 +245,41 @@ static struct sk_buff *ionic_rx_frags(struct net_device *netdev,
        stats = q_to_rx_stats(q);
 
        buf_info = &desc_info->bufs[0];
-
        prefetchw(buf_info->page);
 
        skb = napi_get_frags(&q_to_qcq(q)->napi);
        if (unlikely(!skb)) {
                net_warn_ratelimited("%s: SKB alloc failed on %s!\n",
-                                    dev_name(dev), q->name);
+                                    dev_name(q->dev), q->name);
                stats->alloc_err++;
                return NULL;
        }
 
-       i = num_sg_elems + 1;
-       do {
-               if (unlikely(!buf_info->page)) {
-                       dev_kfree_skb(skb);
-                       return NULL;
-               }
-
-               if (headroom)
-                       frag_len = min_t(u16, len, IONIC_XDP_MAX_LINEAR_MTU + VLAN_ETH_HLEN);
-               else
-                       frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));
-               len -= frag_len;
-
-               if (!synced)
-                       dma_sync_single_range_for_cpu(dev, ionic_rx_buf_pa(buf_info),
-                                                     headroom, frag_len, DMA_FROM_DEVICE);
-
-               skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
-                               buf_info->page, buf_info->page_offset + headroom,
-                               frag_len, IONIC_PAGE_SIZE);
-
-               if (!ionic_rx_buf_recycle(q, buf_info, frag_len)) {
-                       dma_unmap_page(dev, buf_info->dma_addr,
-                                      IONIC_PAGE_SIZE, DMA_FROM_DEVICE);
-                       buf_info->page = NULL;
-               }
-
-               /* only needed on the first buffer */
-               if (headroom)
-                       headroom = 0;
+       if (headroom)
+               frag_len = min_t(u16, len,
+                                IONIC_XDP_MAX_LINEAR_MTU + VLAN_ETH_HLEN);
+       else
+               frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));
 
-               buf_info++;
+       if (unlikely(!buf_info->page))
+               goto err_bad_buf_page;
+       ionic_rx_add_skb_frag(q, skb, buf_info, headroom, frag_len, synced);
+       len -= frag_len;
+       buf_info++;
 
-               i--;
-       } while (i > 0);
+       for (i = 0; i < num_sg_elems; i++, buf_info++) {
+               if (unlikely(!buf_info->page))
+                       goto err_bad_buf_page;
+               frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));
+               ionic_rx_add_skb_frag(q, skb, buf_info, 0, frag_len, synced);
+               len -= frag_len;
+       }
 
        return skb;
+
+err_bad_buf_page:
+       dev_kfree_skb(skb);
+       return NULL;
 }
 
 static struct sk_buff *ionic_rx_copybreak(struct net_device *netdev,
@@ -641,6 +648,8 @@ static void ionic_rx_clean(struct ionic_queue *q,
        struct bpf_prog *xdp_prog;
        unsigned int headroom;
        struct sk_buff *skb;
+       bool synced = false;
+       bool use_copybreak;
        u16 len;
 
        stats = q_to_rx_stats(q);
@@ -655,17 +664,20 @@ static void ionic_rx_clean(struct ionic_queue *q,
        stats->bytes += len;
 
        xdp_prog = READ_ONCE(q->lif->xdp_prog);
-       if (xdp_prog &&
-           ionic_run_xdp(stats, netdev, xdp_prog, q, desc_info->bufs, len))
-               return;
+       if (xdp_prog) {
+               if (ionic_run_xdp(stats, netdev, xdp_prog, q, desc_info->bufs, len))
+                       return;
+               synced = true;
+       }
 
        headroom = q->xdp_rxq_info ? XDP_PACKET_HEADROOM : 0;
-       if (len <= q->lif->rx_copybreak)
+       use_copybreak = len <= q->lif->rx_copybreak;
+       if (use_copybreak)
                skb = ionic_rx_copybreak(netdev, q, desc_info,
-                                        headroom, len, !!xdp_prog);
+                                        headroom, len, synced);
        else
-               skb = ionic_rx_frags(netdev, q, desc_info, headroom, len,
-                                    comp->num_sg_elems, !!xdp_prog);
+               skb = ionic_rx_build_skb(q, desc_info, headroom, len,
+                                        comp->num_sg_elems, synced);
 
        if (unlikely(!skb)) {
                stats->dropped++;
@@ -732,7 +744,7 @@ static void ionic_rx_clean(struct ionic_queue *q,
                }
        }
 
-       if (len <= q->lif->rx_copybreak)
+       if (use_copybreak)
                napi_gro_receive(&qcq->napi, skb);
        else
                napi_gro_frags(&qcq->napi);