vmxnet3: must split too big fragments

vmxnet3 has a 16Kbytes limit per tx descriptor, that happened to work
as long as we provided PAGE_SIZE fragments.

Our stack can now build larger fragments, so we need to split them to
the 16kbytes boundary.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: jongman heo <jongman.heo@samsung.com>
Tested-by: jongman heo <jongman.heo@samsung.com>
Cc: Shreyas Bhatewara <sbhatewara@vmware.com>
Reviewed-by: Bhavesh Davda <bhavesh@vmware.com>
Signed-off-by: Shreyas Bhatewara <sbhatewara@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index ce9d4f2c9776e08d1b543f18de8cb7100fe43a86..0ae1bcc6da730fecd4267f0076b3f3ef422ea7ce 100644 (file)
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -744,28 +744,43 @@ vmxnet3_map_pkt(struct sk_buff *skb, struct vmxnet3_tx_ctx *ctx,
 
        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i];
+               u32 buf_size;
 
-               tbi = tq->buf_info + tq->tx_ring.next2fill;
-               tbi->map_type = VMXNET3_MAP_PAGE;
-               tbi->dma_addr = skb_frag_dma_map(&adapter->pdev->dev, frag,
-                                                0, skb_frag_size(frag),
-                                                DMA_TO_DEVICE);
+               buf_offset = 0;
+               len = skb_frag_size(frag);
+               while (len) {
+                       tbi = tq->buf_info + tq->tx_ring.next2fill;
+                       if (len < VMXNET3_MAX_TX_BUF_SIZE) {
+                               buf_size = len;
+                               dw2 |= len;
+                       } else {
+                               buf_size = VMXNET3_MAX_TX_BUF_SIZE;
+                               /* spec says that for TxDesc.len, 0 == 2^14 */
+                       }
+                       tbi->map_type = VMXNET3_MAP_PAGE;
+                       tbi->dma_addr = skb_frag_dma_map(&adapter->pdev->dev, frag,
+                                                        buf_offset, buf_size,
+                                                        DMA_TO_DEVICE);
 
-               tbi->len = skb_frag_size(frag);
+                       tbi->len = buf_size;
 
-               gdesc = tq->tx_ring.base + tq->tx_ring.next2fill;
-               BUG_ON(gdesc->txd.gen == tq->tx_ring.gen);
+                       gdesc = tq->tx_ring.base + tq->tx_ring.next2fill;
+                       BUG_ON(gdesc->txd.gen == tq->tx_ring.gen);
 
-               gdesc->txd.addr = cpu_to_le64(tbi->dma_addr);
-               gdesc->dword[2] = cpu_to_le32(dw2 | skb_frag_size(frag));
-               gdesc->dword[3] = 0;
+                       gdesc->txd.addr = cpu_to_le64(tbi->dma_addr);
+                       gdesc->dword[2] = cpu_to_le32(dw2);
+                       gdesc->dword[3] = 0;
 
-               dev_dbg(&adapter->netdev->dev,
-                       "txd[%u]: 0x%llu %u %u\n",
-                       tq->tx_ring.next2fill, le64_to_cpu(gdesc->txd.addr),
-                       le32_to_cpu(gdesc->dword[2]), gdesc->dword[3]);
-               vmxnet3_cmd_ring_adv_next2fill(&tq->tx_ring);
-               dw2 = tq->tx_ring.gen << VMXNET3_TXD_GEN_SHIFT;
+                       dev_dbg(&adapter->netdev->dev,
+                               "txd[%u]: 0x%llu %u %u\n",
+                               tq->tx_ring.next2fill, le64_to_cpu(gdesc->txd.addr),
+                               le32_to_cpu(gdesc->dword[2]), gdesc->dword[3]);
+                       vmxnet3_cmd_ring_adv_next2fill(&tq->tx_ring);
+                       dw2 = tq->tx_ring.gen << VMXNET3_TXD_GEN_SHIFT;
+
+                       len -= buf_size;
+                       buf_offset += buf_size;
+               }
        }
 
        ctx->eop_txd = gdesc;
@@ -886,6 +901,18 @@ vmxnet3_prepare_tso(struct sk_buff *skb,
        }
 }
 
+static int txd_estimate(const struct sk_buff *skb)
+{
+       int count = VMXNET3_TXD_NEEDED(skb_headlen(skb)) + 1;
+       int i;
+
+       for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+               const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i];
+
+               count += VMXNET3_TXD_NEEDED(skb_frag_size(frag));
+       }
+       return count;
+}
 
 /*
  * Transmits a pkt thru a given tq
@@ -914,9 +941,7 @@ vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
        union Vmxnet3_GenericDesc tempTxDesc;
 #endif
 
-       /* conservatively estimate # of descriptors to use */
-       count = VMXNET3_TXD_NEEDED(skb_headlen(skb)) +
-               skb_shinfo(skb)->nr_frags + 1;
+       count = txd_estimate(skb);
 
        ctx.ipv4 = (vlan_get_protocol(skb) == cpu_to_be16(ETH_P_IP));