X-Git-Url: https://bbs.cooldavid.org/git/?a=blobdiff_plain;f=drivers%2Fnet%2Fcxgb4vf%2Fsge.c;h=ecf0770bf0ff60bde745ff12c00e337a4aa54982;hb=eb6c503db3619c43b5aad0ced82e9d91c034ced5;hp=6a6e18b0724884ff4e3951dee55fc2cf4f186b92;hpb=b94e72e23e3ededa23cf18973ffc9a03c7ea8d04;p=net-next-2.6.git

diff --git a/drivers/net/cxgb4vf/sge.c b/drivers/net/cxgb4vf/sge.c
index 6a6e18b0724..ecf0770bf0f 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.
@@ -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;
 }
 
 /**