3c59x: Add dma error checking and recovery

Noted that 3c59x has no checks on transmit for failed DMA mappings, and no
ability to unmap fragments when a single map fails in the middle of a transmit.
This patch provides error checking to ensure that dma mappings work properly,
and unrolls an skb mapping if a fragmented skb transmission has a mapping
failure to prevent leaks.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Linux Kernel list <linux-kernel@vger.kernel.org>
CC: "David S. Miller" <davem@davemloft.net>
CC: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>

1 files changed, 41 insertions, 9 deletions

diff --git a/drivers/net/ethernet/3com/3c59x.c b/drivers/net/ethernet/3com/3c59x.c
index 3fe45c705933..8ab87ff6a9e6 100644
--- a/drivers/net/ethernet/3com/3c59x.c
+++ b/drivers/net/ethernet/3com/3c59x.c
@@ -2129,6 +2129,7 @@ boomerang_start_xmit(struct sk_buff *skb, struct net_device *dev)
         int entry = vp->cur_tx % TX_RING_SIZE;
         struct boom_tx_desc *prev_entry = &vp->tx_ring[(vp->cur_tx-1) % TX_RING_SIZE];
         unsigned long flags;
+        dma_addr_t dma_addr;
 
         if (vortex_debug > 6) {
                 pr_debug("boomerang_start_xmit()\n");
@@ -2163,24 +2164,48 @@ boomerang_start_xmit(struct sk_buff *skb, struct net_device *dev)
                         vp->tx_ring[entry].status = cpu_to_le32(skb->len | TxIntrUploaded | AddTCPChksum | AddUDPChksum);
 
         if (!skb_shinfo(skb)->nr_frags) {
-                vp->tx_ring[entry].frag[0].addr = cpu_to_le32(pci_map_single(VORTEX_PCI(vp), skb->data,
-                                                                                skb->len, PCI_DMA_TODEVICE));
+                dma_addr = pci_map_single(VORTEX_PCI(vp), skb->data, skb->len,
+                                          PCI_DMA_TODEVICE);
+                if (dma_mapping_error(&VORTEX_PCI(vp)->dev, dma_addr))
+                        goto out_dma_err;
+
+                vp->tx_ring[entry].frag[0].addr = cpu_to_le32(dma_addr);
                 vp->tx_ring[entry].frag[0].length = cpu_to_le32(skb->len | LAST_FRAG);
         } else {
                 int i;
 
-                vp->tx_ring[entry].frag[0].addr = cpu_to_le32(pci_map_single(VORTEX_PCI(vp), skb->data,
-                                                                                skb_headlen(skb), PCI_DMA_TODEVICE));
+                dma_addr = pci_map_single(VORTEX_PCI(vp), skb->data,
+                                          skb_headlen(skb), PCI_DMA_TODEVICE);
+                if (dma_mapping_error(&VORTEX_PCI(vp)->dev, dma_addr))
+                        goto out_dma_err;
+
+                vp->tx_ring[entry].frag[0].addr = cpu_to_le32(dma_addr);
                 vp->tx_ring[entry].frag[0].length = cpu_to_le32(skb_headlen(skb));
 
                 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
+                        dma_addr = skb_frag_dma_map(&VORTEX_PCI(vp)->dev, frag,
+                                                    frag->page_offset,
+                                                    frag->size,
+                                                    DMA_TO_DEVICE);
+                        if (dma_mapping_error(&VORTEX_PCI(vp)->dev, dma_addr)) {
+                                for(i = i-1; i >= 0; i--)
+                                        dma_unmap_page(&VORTEX_PCI(vp)->dev,
+                                                       le32_to_cpu(vp->tx_ring[entry].frag[i+1].addr),
+                                                       le32_to_cpu(vp->tx_ring[entry].frag[i+1].length),
+                                                       DMA_TO_DEVICE);
+
+                                pci_unmap_single(VORTEX_PCI(vp),
+                                                 le32_to_cpu(vp->tx_ring[entry].frag[0].addr),
+                                                 le32_to_cpu(vp->tx_ring[entry].frag[0].length),
+                                                 PCI_DMA_TODEVICE);
+
+                                goto out_dma_err;
+                        }
+
                         vp->tx_ring[entry].frag[i+1].addr =
-                                        cpu_to_le32(skb_frag_dma_map(
-                                                &VORTEX_PCI(vp)->dev,
-                                                frag,
-                                                frag->page_offset, frag->size, DMA_TO_DEVICE));
+                                                cpu_to_le32(dma_addr);
 
                         if (i == skb_shinfo(skb)->nr_frags-1)
                                         vp->tx_ring[entry].frag[i+1].length = cpu_to_le32(skb_frag_size(frag)|LAST_FRAG);
@@ -2189,7 +2214,10 @@ boomerang_start_xmit(struct sk_buff *skb, struct net_device *dev)
                 }
         }
 #else
-        vp->tx_ring[entry].addr = cpu_to_le32(pci_map_single(VORTEX_PCI(vp), skb->data, skb->len, PCI_DMA_TODEVICE));
+        dma_addr = cpu_to_le32(pci_map_single(VORTEX_PCI(vp), skb->data, skb->len, PCI_DMA_TODEVICE));
+        if (dma_mapping_error(&VORTEX_PCI(vp)->dev, dma_addr))
+                goto out_dma_err;
+        vp->tx_ring[entry].addr = cpu_to_le32(dma_addr);
         vp->tx_ring[entry].length = cpu_to_le32(skb->len | LAST_FRAG);
         vp->tx_ring[entry].status = cpu_to_le32(skb->len | TxIntrUploaded);
 #endif
@@ -2217,7 +2245,11 @@ boomerang_start_xmit(struct sk_buff *skb, struct net_device *dev)
         skb_tx_timestamp(skb);
         iowrite16(DownUnstall, ioaddr + EL3_CMD);
         spin_unlock_irqrestore(&vp->lock, flags);
+out:
         return NETDEV_TX_OK;
+out_dma_err:
+        dev_err(&VORTEX_PCI(vp)->dev, "Error mapping dma buffer\n");
+        goto out;
 }
 
 /* The interrupt handler does all of the Rx thread work and cleans up