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>

1 files changed, 1 insertions, 7 deletions

diff --git a/drivers/infiniband/hw/nes/nes_cm.c b/drivers/infiniband/hw/nes/nes_cm.c
index a09caf5b387d..dbd9a75474e3 100644
--- 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) {