jme: Fix unmap error (Causing system freeze)

This patch add the missing dma_unmap().
Which solved the critical issue of system freeze on heavy load.

Michal Miroslaw's rejected patch:
[PATCH v2 10/46] net: jme: convert to generic DMA API
Pointed out the issue also, thank you Michal.
But the fix was incorrect. It would unmap needed address
when low memory.

Got lots of feedback from End user and Gentoo Bugzilla.
https://bugs.gentoo.org/show_bug.cgi?id=373109
Thank you all. :)

diff --git a/jme.c b/jme.c
index 4e4613a3dc2ffd80c765ee3d13d56dcc78cda5fd..9da34cb4fb6304d0423a48e24b9dc4060684605d 100644 (file)
--- a/jme.c
+++ b/jme.c
@@ -769,6 +769,7 @@ jme_make_new_rx_buf(struct jme_adapter *jme, int i)
        struct jme_ring *rxring = &(jme->rxring[0]);
        struct jme_buffer_info *rxbi = rxring->bufinf + i;
        struct sk_buff *skb;
+       dma_addr_t mapping;
 
        skb = netdev_alloc_skb(jme->dev,
                jme->dev->mtu + RX_EXTRA_LEN);
@@ -778,14 +779,21 @@ jme_make_new_rx_buf(struct jme_adapter *jme, int i)
        skb->dev = jme->dev;
 #endif
 
+       mapping = pci_map_page(jme->pdev, virt_to_page(skb->data),
+                              offset_in_page(skb->data), skb_tailroom(skb),
+                              PCI_DMA_FROMDEVICE);
+       if (unlikely(pci_dma_mapping_error(jme->pdev, mapping))) {
+               dev_kfree_skb(skb);
+               return -ENOMEM;
+       }
+
+       if (likely(rxbi->mapping))
+               pci_unmap_page(jme->pdev, rxbi->mapping,
+                              rxbi->len, PCI_DMA_FROMDEVICE);
+
        rxbi->skb = skb;
        rxbi->len = skb_tailroom(skb);
-       rxbi->mapping = pci_map_page(jme->pdev,
-                                       virt_to_page(skb->data),
-                                       offset_in_page(skb->data),
-                                       rxbi->len,
-                                       PCI_DMA_FROMDEVICE);
-
+       rxbi->mapping = mapping;
        return 0;
 }