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Commit 5962c2c8 authored by Faisal Latif's avatar Faisal Latif Committed by Roland Dreier
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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: default avatarFaisal Latif <faisal.latif@intel.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 79fc3d74

drivers/infiniband/hw/nes/nes_cm.c

+1 −7
Original line number Original line Diff line number Diff line
@@ -446,8 +446,8 @@ int schedule_nes_timer(struct nes_cm_node *cm_node, struct sk_buff *skb, 
		if (ret != NETDEV_TX_OK) {

		if (ret != NETDEV_TX_OK) {

			nes_debug(NES_DBG_CM, "Error sending packet %p "

			nes_debug(NES_DBG_CM, "Error sending packet %p "

				"(jiffies = %lu)\n", new_send, jiffies);

				"(jiffies = %lu)\n", new_send, jiffies);

			atomic_dec(&new_send->skb->users);

			new_send->timetosend = jiffies;

			new_send->timetosend = jiffies;

			ret = NETDEV_TX_OK;

		} else {

		} else {

			cm_packets_sent++;

			cm_packets_sent++;

			if (!send_retrans) {

			if (!send_retrans) {
@@ -631,7 +631,6 @@ static void nes_cm_timer_tick(unsigned long pass) 
				nes_debug(NES_DBG_CM, "rexmit failed for "

				nes_debug(NES_DBG_CM, "rexmit failed for "

					"node=%p\n", cm_node);

					"node=%p\n", cm_node);

				cm_packets_bounced++;

				cm_packets_bounced++;

				atomic_dec(&send_entry->skb->users);

				send_entry->retrycount--;

				send_entry->retrycount--;

				nexttimeout = jiffies + NES_SHORT_TIME;

				nexttimeout = jiffies + NES_SHORT_TIME;

				settimer = 1;

				settimer = 1;
@@ -667,11 +666,6 @@ static void nes_cm_timer_tick(unsigned long pass) 




		spin_unlock_irqrestore(&cm_node->retrans_list_lock, flags);

		spin_unlock_irqrestore(&cm_node->retrans_list_lock, flags);

		rem_ref_cm_node(cm_node->cm_core, cm_node);

		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) {

	if (settimer) {