[PATCH v2 01/41] hw/net/net_tx_pkt: Decouple implementation from PCI

[Akihiko Odaki]

This is intended to be followed by another change for the interface.
It also fixes the leak of memory mapping when the specified memory is
partially mapped.

Fixes: e263cd49c7 ("Packet abstraction for VMWARE network devices")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 hw/net/net_tx_pkt.h |  9 ++++++++
 hw/net/net_tx_pkt.c | 53 ++++++++++++++++++++++++++++-----------------
 2 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/hw/net/net_tx_pkt.h b/hw/net/net_tx_pkt.h
index e5ce6f20bc..5eb123ef90 100644
--- a/hw/net/net_tx_pkt.h
+++ b/hw/net/net_tx_pkt.h
@@ -153,6 +153,15 @@ void net_tx_pkt_dump(struct NetTxPkt *pkt);
  */
 void net_tx_pkt_reset(struct NetTxPkt *pkt, PCIDevice *dev);
 
+/**
+ * Unmap a fragment mapped from a PCI device.
+ *
+ * @context:        PCI device owning fragment
+ * @base:           pointer to fragment
+ * @len:            length of fragment
+ */
+void net_tx_pkt_unmap_frag_pci(void *context, void *base, size_t len);
+
 /**
  * Send packet to qemu. handles sw offloads if vhdr is not supported.
  *
diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index 8dc8568ba2..aca12ff035 100644
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -384,10 +384,9 @@ void net_tx_pkt_setup_vlan_header_ex(struct NetTxPkt *pkt,
     }
 }
 
-bool net_tx_pkt_add_raw_fragment(struct NetTxPkt *pkt, hwaddr pa,
-    size_t len)
+static bool net_tx_pkt_add_raw_fragment_common(struct NetTxPkt *pkt,
+                                               void *base, size_t len)
 {
-    hwaddr mapped_len = 0;
     struct iovec *ventry;
     assert(pkt);
 
@@ -395,23 +394,12 @@ bool net_tx_pkt_add_raw_fragment(struct NetTxPkt *pkt, 
hwaddr pa,
         return false;
     }
 
-    if (!len) {
-        return true;
-     }
-
     ventry = &pkt->raw[pkt->raw_frags];
-    mapped_len = len;
+    ventry->iov_base = base;
+    ventry->iov_len = len;
+    pkt->raw_frags++;
 
-    ventry->iov_base = pci_dma_map(pkt->pci_dev, pa,
-                                   &mapped_len, DMA_DIRECTION_TO_DEVICE);
-
-    if ((ventry->iov_base != NULL) && (len == mapped_len)) {
-        ventry->iov_len = mapped_len;
-        pkt->raw_frags++;
-        return true;
-    } else {
-        return false;
-    }
+    return true;
 }
 
 bool net_tx_pkt_has_fragments(struct NetTxPkt *pkt)
@@ -465,8 +453,9 @@ void net_tx_pkt_reset(struct NetTxPkt *pkt, PCIDevice 
*pci_dev)
         assert(pkt->raw);
         for (i = 0; i < pkt->raw_frags; i++) {
             assert(pkt->raw[i].iov_base);
-            pci_dma_unmap(pkt->pci_dev, pkt->raw[i].iov_base,
-                          pkt->raw[i].iov_len, DMA_DIRECTION_TO_DEVICE, 0);
+            net_tx_pkt_unmap_frag_pci(pkt->pci_dev,
+                                      pkt->raw[i].iov_base,
+                                      pkt->raw[i].iov_len);
         }
     }
     pkt->pci_dev = pci_dev;
@@ -476,6 +465,30 @@ void net_tx_pkt_reset(struct NetTxPkt *pkt, PCIDevice 
*pci_dev)
     pkt->l4proto = 0;
 }
 
+void net_tx_pkt_unmap_frag_pci(void *context, void *base, size_t len)
+{
+    pci_dma_unmap(context, base, len, DMA_DIRECTION_TO_DEVICE, 0);
+}
+
+bool net_tx_pkt_add_raw_fragment(struct NetTxPkt *pkt, hwaddr pa,
+    size_t len)
+{
+    dma_addr_t mapped_len = len;
+    void *base = pci_dma_map(pkt->pci_dev, pa, &mapped_len,
+                             DMA_DIRECTION_TO_DEVICE);
+    if (!base) {
+        return false;
+    }
+
+    if (mapped_len != len ||
+        !net_tx_pkt_add_raw_fragment_common(pkt, base, len)) {
+        net_tx_pkt_unmap_frag_pci(pkt->pci_dev, base, mapped_len);
+        return false;
+    }
+
+    return true;
+}
+
 static void net_tx_pkt_do_sw_csum(struct NetTxPkt *pkt,
                                   struct iovec *iov, uint32_t iov_len,
                                   uint16_t csl)
-- 
2.40.0