be2net: Fix to avoid a crash seen on PPC with LRO and Jumbo frames.

While testing the driver on PPC, we ran into a crash with LRO, Jumbo frames.
With CONFIG_PPC_64K_PAGES configured (a default in PPC), MAX_SKB_FRAGS drops to 3 and we were crossing the array limits on skb_shinfo(skb)->frags[].
Now we coalesce the frags from the same physical page into one slot in
skb_shinfo(skb)->frags[] and go to the next index when the frag is from

different physical page.

This patch is against the net-2.6 tree.

Signed-off-by: Ajit Khaparde <ajitk@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/benet/be.h b/drivers/net/benet/be.h
index f703758..5b4bf3d 100644 (file)
--- a/drivers/net/benet/be.h
+++ b/drivers/net/benet/be.h
@@ -73,7 +73,7 @@ static inline char *nic_name(struct pci_dev *pdev)
 #define RX_FRAGS_REFILL_WM     (RX_Q_LEN - MAX_RX_POST)
 
 #define BE_MAX_LRO_DESCRIPTORS  16
-#define BE_MAX_FRAGS_PER_FRAME  16
+#define BE_MAX_FRAGS_PER_FRAME  (min((u32) 16, (u32) MAX_SKB_FRAGS))
 
 struct be_dma_mem {
        void *va;

diff --git a/drivers/net/benet/be_ethtool.c b/drivers/net/benet/be_ethtool.c
index 9592f22..cccc541 100644 (file)
--- a/drivers/net/benet/be_ethtool.c
+++ b/drivers/net/benet/be_ethtool.c
@@ -162,8 +162,8 @@ be_set_coalesce(struct net_device *netdev, struct ethtool_coalesce *coalesce)
                return -EINVAL;
 
        adapter->max_rx_coal = coalesce->rx_max_coalesced_frames;
-       if (adapter->max_rx_coal > MAX_SKB_FRAGS)
-               adapter->max_rx_coal = MAX_SKB_FRAGS - 1;
+       if (adapter->max_rx_coal > BE_MAX_FRAGS_PER_FRAME)
+               adapter->max_rx_coal = BE_MAX_FRAGS_PER_FRAME;
 
        /* if AIC is being turned on now, start with an EQD of 0 */
        if (rx_eq->enable_aic == 0 &&

diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index 66c10c8..308eb09 100644 (file)
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -666,7 +666,7 @@ static void skb_fill_rx_data(struct be_adapter *adapter,
 {
        struct be_queue_info *rxq = &adapter->rx_obj.q;
        struct be_rx_page_info *page_info;
-       u16 rxq_idx, i, num_rcvd;
+       u16 rxq_idx, i, num_rcvd, j;
        u32 pktsize, hdr_len, curr_frag_len;
        u8 *start;
 
@@ -709,22 +709,33 @@ static void skb_fill_rx_data(struct be_adapter *adapter,
 
        /* More frags present for this completion */
        pktsize -= curr_frag_len; /* account for above copied frag */
-       for (i = 1; i < num_rcvd; i++) {
+       for (i = 1, j = 0; i < num_rcvd; i++) {
                index_inc(&rxq_idx, rxq->len);
                page_info = get_rx_page_info(adapter, rxq_idx);
 
                curr_frag_len = min(pktsize, rx_frag_size);
 
-               skb_shinfo(skb)->frags[i].page = page_info->page;
-               skb_shinfo(skb)->frags[i].page_offset = page_info->page_offset;
-               skb_shinfo(skb)->frags[i].size = curr_frag_len;
+               /* Coalesce all frags from the same physical page in one slot */
+               if (page_info->page_offset == 0) {
+                       /* Fresh page */
+                       j++;
+                       skb_shinfo(skb)->frags[j].page = page_info->page;
+                       skb_shinfo(skb)->frags[j].page_offset =
+                                                       page_info->page_offset;
+                       skb_shinfo(skb)->frags[j].size = 0;
+                       skb_shinfo(skb)->nr_frags++;
+               } else {
+                       put_page(page_info->page);
+               }
+
+               skb_shinfo(skb)->frags[j].size += curr_frag_len;
                skb->len += curr_frag_len;
                skb->data_len += curr_frag_len;
-               skb_shinfo(skb)->nr_frags++;
                pktsize -= curr_frag_len;
 
                memset(page_info, 0, sizeof(*page_info));
        }
+       BUG_ON(j > MAX_SKB_FRAGS);
 
 done:
        be_rx_stats_update(adapter, pktsize, num_rcvd);
@@ -786,7 +797,7 @@ static void be_rx_compl_process_lro(struct be_adapter *adapter,
        struct skb_frag_struct rx_frags[BE_MAX_FRAGS_PER_FRAME];
        struct be_queue_info *rxq = &adapter->rx_obj.q;
        u32 num_rcvd, pkt_size, remaining, vlanf, curr_frag_len;
-       u16 i, rxq_idx = 0, vid;
+       u16 i, rxq_idx = 0, vid, j;
 
        num_rcvd = AMAP_GET_BITS(struct amap_eth_rx_compl, numfrags, rxcp);
        pkt_size = AMAP_GET_BITS(struct amap_eth_rx_compl, pktsize, rxcp);
@@ -794,20 +805,28 @@ static void be_rx_compl_process_lro(struct be_adapter *adapter,
        rxq_idx = AMAP_GET_BITS(struct amap_eth_rx_compl, fragndx, rxcp);
 
        remaining = pkt_size;
-       for (i = 0; i < num_rcvd; i++) {
+       for (i = 0, j = -1; i < num_rcvd; i++) {
                page_info = get_rx_page_info(adapter, rxq_idx);
 
                curr_frag_len = min(remaining, rx_frag_size);
 
-               rx_frags[i].page = page_info->page;
-               rx_frags[i].page_offset = page_info->page_offset;
-               rx_frags[i].size = curr_frag_len;
-               remaining -= curr_frag_len;
+               /* Coalesce all frags from the same physical page in one slot */
+               if (i == 0 || page_info->page_offset == 0) {
+                       /* First frag or Fresh page */
+                       j++;
+                       rx_frags[j].page = page_info->page;
+                       rx_frags[j].page_offset = page_info->page_offset;
+                       rx_frags[j].size = 0;
+               } else {
+                       put_page(page_info->page);
+               }
+               rx_frags[j].size += curr_frag_len;
 
+               remaining -= curr_frag_len;
                index_inc(&rxq_idx, rxq->len);
-
                memset(page_info, 0, sizeof(*page_info));
        }
+       BUG_ON(j > MAX_SKB_FRAGS);
 
        if (likely(!vlanf)) {
                lro_receive_frags(&adapter->rx_obj.lro_mgr, rx_frags, pkt_size,