1 files changed, 75 insertions, 47 deletions

diff --git a/drivers/net/cxgb4vf/sge.c b/drivers/net/cxgb4vf/sge.c
index f10864ddafbe..ecf0770bf0ff 100644
--- a/drivers/net/cxgb4vf/sge.c
+++ b/drivers/net/cxgb4vf/sge.c
@@ -154,13 +154,14 @@ enum {
          */
         RX_COPY_THRES = 256,
         RX_PULL_LEN = 128,
-};
 
-/*
- * Can't define this in the above enum because PKTSHIFT isn't a constant in
- * the VF Driver ...
- */
-#define RX_PKT_PULL_LEN (RX_PULL_LEN + PKTSHIFT)
+        /*
+         * Main body length for sk_buffs used for RX Ethernet packets with
+         * fragments.  Should be >= RX_PULL_LEN but possibly bigger to give
+         * pskb_may_pull() some room.
+         */
+        RX_SKB_LEN = 512,
+};
 
 /*
  * Software state per TX descriptor.
@@ -1355,6 +1356,67 @@ out_free:
 }
 
 /**
+ *      t4vf_pktgl_to_skb - build an sk_buff from a packet gather list
+ *      @gl: the gather list
+ *      @skb_len: size of sk_buff main body if it carries fragments
+ *      @pull_len: amount of data to move to the sk_buff's main body
+ *
+ *      Builds an sk_buff from the given packet gather list.  Returns the
+ *      sk_buff or %NULL if sk_buff allocation failed.
+ */
+struct sk_buff *t4vf_pktgl_to_skb(const struct pkt_gl *gl,
+                                  unsigned int skb_len, unsigned int pull_len)
+{
+        struct sk_buff *skb;
+        struct skb_shared_info *ssi;
+
+        /*
+         * If the ingress packet is small enough, allocate an skb large enough
+         * for all of the data and copy it inline.  Otherwise, allocate an skb
+         * with enough room to pull in the header and reference the rest of
+         * the data via the skb fragment list.
+         *
+         * Below we rely on RX_COPY_THRES being less than the smallest Rx
+         * buff!  size, which is expected since buffers are at least
+         * PAGE_SIZEd.  In this case packets up to RX_COPY_THRES have only one
+         * fragment.
+         */
+        if (gl->tot_len <= RX_COPY_THRES) {
+                /* small packets have only one fragment */
+                skb = alloc_skb(gl->tot_len, GFP_ATOMIC);
+                if (unlikely(!skb))
+                        goto out;
+                __skb_put(skb, gl->tot_len);
+                skb_copy_to_linear_data(skb, gl->va, gl->tot_len);
+        } else {
+                skb = alloc_skb(skb_len, GFP_ATOMIC);
+                if (unlikely(!skb))
+                        goto out;
+                __skb_put(skb, pull_len);
+                skb_copy_to_linear_data(skb, gl->va, pull_len);
+
+                ssi = skb_shinfo(skb);
+                ssi->frags[0].page = gl->frags[0].page;
+                ssi->frags[0].page_offset = gl->frags[0].page_offset + pull_len;
+                ssi->frags[0].size = gl->frags[0].size - pull_len;
+                if (gl->nfrags > 1)
+                        memcpy(&ssi->frags[1], &gl->frags[1],
+                               (gl->nfrags-1) * sizeof(skb_frag_t));
+                ssi->nr_frags = gl->nfrags;
+
+                skb->len = gl->tot_len;
+                skb->data_len = skb->len - pull_len;
+                skb->truesize += skb->data_len;
+
+                /* Get a reference for the last page, we don't own it */
+                get_page(gl->frags[gl->nfrags - 1].page);
+        }
+
+out:
+        return skb;
+}
+
+/**
  *      t4vf_pktgl_free - free a packet gather list
  *      @gl: the gather list
  *
@@ -1463,10 +1525,8 @@ int t4vf_ethrx_handler(struct sge_rspq *rspq, const __be64 *rsp,
 {
         struct sk_buff *skb;
         struct port_info *pi;
-        struct skb_shared_info *ssi;
         const struct cpl_rx_pkt *pkt = (void *)&rsp[1];
         bool csum_ok = pkt->csum_calc && !pkt->err_vec;
-        unsigned int len = be16_to_cpu(pkt->len);
         struct sge_eth_rxq *rxq = container_of(rspq, struct sge_eth_rxq, rspq);
 
         /*
@@ -1481,42 +1541,14 @@ int t4vf_ethrx_handler(struct sge_rspq *rspq, const __be64 *rsp,
         }
 
         /*
-         * If the ingress packet is small enough, allocate an skb large enough
-         * for all of the data and copy it inline.  Otherwise, allocate an skb
-         * with enough room to pull in the header and reference the rest of
-         * the data via the skb fragment list.
+         * Convert the Packet Gather List into an skb.
          */
-        if (len <= RX_COPY_THRES) {
-                /* small packets have only one fragment */
-                skb = alloc_skb(gl->frags[0].size, GFP_ATOMIC);
-                if (!skb)
-                        goto nomem;
-                __skb_put(skb, gl->frags[0].size);
-                skb_copy_to_linear_data(skb, gl->va, gl->frags[0].size);
-        } else {
-                skb = alloc_skb(RX_PKT_PULL_LEN, GFP_ATOMIC);
-                if (!skb)
-                        goto nomem;
-                __skb_put(skb, RX_PKT_PULL_LEN);
-                skb_copy_to_linear_data(skb, gl->va, RX_PKT_PULL_LEN);
-
-                ssi = skb_shinfo(skb);
-                ssi->frags[0].page = gl->frags[0].page;
-                ssi->frags[0].page_offset = (gl->frags[0].page_offset +
-                                             RX_PKT_PULL_LEN);
-                ssi->frags[0].size = gl->frags[0].size - RX_PKT_PULL_LEN;
-                if (gl->nfrags > 1)
-                        memcpy(&ssi->frags[1], &gl->frags[1],
-                               (gl->nfrags-1) * sizeof(skb_frag_t));
-                ssi->nr_frags = gl->nfrags;
-                skb->len = len + PKTSHIFT;
-                skb->data_len = skb->len - RX_PKT_PULL_LEN;
-                skb->truesize += skb->data_len;
-
-                /* Get a reference for the last page, we don't own it */
-                get_page(gl->frags[gl->nfrags - 1].page);
+        skb = t4vf_pktgl_to_skb(gl, RX_SKB_LEN, RX_PULL_LEN);
+        if (unlikely(!skb)) {
+                t4vf_pktgl_free(gl);
+                rxq->stats.rx_drops++;
+                return 0;
         }
-
         __skb_pull(skb, PKTSHIFT);
         skb->protocol = eth_type_trans(skb, rspq->netdev);
         skb_record_rx_queue(skb, rspq->idx);
@@ -1549,11 +1581,6 @@ int t4vf_ethrx_handler(struct sge_rspq *rspq, const __be64 *rsp,
                 netif_receive_skb(skb);
 
         return 0;
-
-nomem:
-        t4vf_pktgl_free(gl);
-        rxq->stats.rx_drops++;
-        return 0;
 }
 
 /**
@@ -1679,6 +1706,7 @@ int process_responses(struct sge_rspq *rspq, int budget)
                                 }
                                 len = RSPD_LEN(len);
                         }
+                        gl.tot_len = len;
 
                         /*
                          * Gather packet fragments.