RDMA/nes: Fix nes_nic_cm_xmit() error handling

We are getting crash or hung situation when we are running network
cable pull tests during RDMA traffic.

In schedule_nes_timer(), we return an error if nes_nic_cm_xmit()
returns failure.  This is changed to success as skb is being put on
the timer routines to be processed later.  In send_syn() case, we are
indicating connect failure once from nes_connect() and the other when
the rexmit retries expires.

The other issue is skb->users which we are incrementing before calling
nes_nic_cm_xmit() which calls dev_queue_xmit() but in case of failure
we are decrementing the skb->users at the same time putting the skb on
the rexmit path.  Even if dev_queue_xmit() fails, the skb->users is
decremented already.  We are removing the decrement of skb->users in
case of failure from both schedule_nes_timer() as well as from
nes_cm_timer_tick().

There is also extra check in nes_cm_timer_tick() for rexmit failure
which does a break from the loop is removed.  This causes problem as
the other nodes have their cm_node->ref_count incremented and are not
processed.

Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/infiniband/hw/nes/nes_cm.c b/drivers/infiniband/hw/nes/nes_cm.c
index a09caf5b387d7b0b44e4216cc4e4227be2e3b7f8..dbd9a75474e3385052e9c972fb545fe31035583c 100644 (file)
--- a/drivers/infiniband/hw/nes/nes_cm.c
+++ b/drivers/infiniband/hw/nes/nes_cm.c
@@ -446,8 +446,8 @@ int schedule_nes_timer(struct nes_cm_node *cm_node, struct sk_buff *skb,
                if (ret != NETDEV_TX_OK) {
                        nes_debug(NES_DBG_CM, "Error sending packet %p "
                                "(jiffies = %lu)\n", new_send, jiffies);
-                       atomic_dec(&new_send->skb->users);
                        new_send->timetosend = jiffies;
+                       ret = NETDEV_TX_OK;
                } else {
                        cm_packets_sent++;
                        if (!send_retrans) {
@@ -631,7 +631,6 @@ static void nes_cm_timer_tick(unsigned long pass)
                                nes_debug(NES_DBG_CM, "rexmit failed for "
                                        "node=%p\n", cm_node);
                                cm_packets_bounced++;
-                               atomic_dec(&send_entry->skb->users);
                                send_entry->retrycount--;
                                nexttimeout = jiffies + NES_SHORT_TIME;
                                settimer = 1;
@@ -667,11 +666,6 @@ static void nes_cm_timer_tick(unsigned long pass)
 
                spin_unlock_irqrestore(&cm_node->retrans_list_lock, flags);
                rem_ref_cm_node(cm_node->cm_core, cm_node);
-               if (ret != NETDEV_TX_OK) {
-                       nes_debug(NES_DBG_CM, "rexmit failed for cm_node=%p\n",
-                               cm_node);
-                       break;
-               }
        }
 
        if (settimer) {