cxgb4vf: fix some errors in Gather List to skb conversion

[net-next-2.6.git] / drivers / net / cxgb4vf / sge.c

diff --git a/drivers/net/cxgb4vf/sge.c b/drivers/net/cxgb4vf/sge.c
index 6a6e18b0724884ff4e3951dee55fc2cf4f186b92..ecf0770bf0ff60bde745ff12c00e337a4aa54982 100644 (file)
--- 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.
@@ -1354,6 +1355,67 @@ out_free:
        return NETDEV_TX_OK;
 }
 
+/**
+ *     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;
 }
 
 /**