tg3: Fix 4k skb error recovery path

On the error recovery resource unwind path, it is possible for the
driver to attempt to unmap a fragment that hadn't been mapped.  This
patch fixes the problem by correcting the "last" parameter supplied.

(cherry picked from commit ba1142e4fb291c7bf124d93596351dca8d226a0f)
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Joe Jin <joe.jin@oracle.com>

diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index 73382fa4d2325aae73c32d722687c6cd1a2f36fd..a4a869cae4532cea0da71812a05419489d5bf07c 100644 (file)
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -6513,7 +6513,7 @@ static void tg3_tx_skb_unmap(struct tg3_napi *tnapi, u32 entry, int last)
                txb = &tnapi->tx_buffers[entry];
        }
 
-       for (i = 0; i < last; i++) {
+       for (i = 0; i <= last; i++) {
                skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
                entry = NEXT_TX(entry);
@@ -6574,7 +6574,7 @@ static int tigon3_dma_hwbug_workaround(struct tg3_napi *tnapi,
                        if (tg3_tx_frag_set(tnapi, entry, budget, new_addr,
                                            new_skb->len, base_flags,
                                            mss, vlan)) {
-                               tg3_tx_skb_unmap(tnapi, save_entry, 0);
+                               tg3_tx_skb_unmap(tnapi, save_entry, -1);
                                dev_kfree_skb(new_skb);
                                ret = -1;
                        }
@@ -6766,11 +6766,10 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
        if (tg3_tx_frag_set(tnapi, &entry, &budget, mapping, len, base_flags |
                          ((skb_shinfo(skb)->nr_frags == 0) ? TXD_FLAG_END : 0),
-                           mss, vlan))
+                           mss, vlan)) {
                would_hit_hwbug = 1;
-
        /* Now loop through additional data fragments, and queue them. */
-       if (skb_shinfo(skb)->nr_frags > 0) {
+       } else if (skb_shinfo(skb)->nr_frags > 0) {
                u32 tmp_mss = mss;
 
                if (!tg3_flag(tp, HW_TSO_1) &&
@@ -6839,7 +6838,7 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
        return NETDEV_TX_OK;
 
 dma_error:
-       tg3_tx_skb_unmap(tnapi, tnapi->tx_prod, i);
+       tg3_tx_skb_unmap(tnapi, tnapi->tx_prod, --i);
        tnapi->tx_buffers[tnapi->tx_prod].skb = NULL;
 drop:
        dev_kfree_skb(skb);
@@ -7292,7 +7291,8 @@ static void tg3_free_rings(struct tg3 *tp)
                        if (!skb)
                                continue;
 
-                       tg3_tx_skb_unmap(tnapi, i, skb_shinfo(skb)->nr_frags);
+                       tg3_tx_skb_unmap(tnapi, i,
+                                        skb_shinfo(skb)->nr_frags - 1);
 
                        dev_kfree_skb_any(skb);
                }
@@ -11531,7 +11531,7 @@ static int tg3_run_loopback(struct tg3 *tp, u32 pktsz, bool tso_loopback)
                        break;
        }
 
-       tg3_tx_skb_unmap(tnapi, tnapi->tx_prod - 1, 0);
+       tg3_tx_skb_unmap(tnapi, tnapi->tx_prod - 1, -1);
        dev_kfree_skb(skb);
 
        if (tx_idx != tnapi->tx_prod)