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Commit 0b545a62 authored by Sathya Perla's avatar Sathya Perla Committed by David S. Miller
Browse files

be2net: fix a possible events_get() race on BE2 



On BE2 chip, an interrupt being raised even when EQ is in un-armed state has
been observed a few times.  This is not expected and has never been
observed on BE3/Lancer chips.

As a consequence, be_msix()::events_get() and be_poll()::events_get()
can race and notify an EQ wrongly causing a CEV UE. The other possible
side-effect would be traffic stalling because after notifying EQ,
napi_schedule() is ignored as NAPI is already running.

This patch fixes this issue by counting events only in be_poll().

Signed-off-by: default avatarSathya Perla <sathya.perla@emulex.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9ce99cf6

drivers/net/ethernet/emulex/benet/be_main.c

+7 −4
Original line number Diff line number Diff line
@@ -2029,7 +2029,8 @@ static irqreturn_t be_msix(int irq, void *dev) 
{

	struct be_eq_obj *eqo = dev;



	event_handle(eqo);

	be_eq_notify(eqo->adapter, eqo->q.id, false, true, 0);

	napi_schedule(&eqo->napi);

	return IRQ_HANDLED;

}
@@ -2125,9 +2126,11 @@ int be_poll(struct napi_struct *napi, int budget) 
{

	struct be_eq_obj *eqo = container_of(napi, struct be_eq_obj, napi);

	struct be_adapter *adapter = eqo->adapter;

	int max_work = 0, work, i;

	int max_work = 0, work, i, num_evts;

	bool tx_done;



	num_evts = events_get(eqo);



	/* Process all TXQs serviced by this EQ */

	for (i = eqo->idx; i < adapter->num_tx_qs; i += adapter->num_evt_qs) {

		tx_done = be_process_tx(adapter, &adapter->tx_obj[i],
@@ -2150,10 +2153,10 @@ int be_poll(struct napi_struct *napi, int budget) 


	if (max_work < budget) {

		napi_complete(napi);

		be_eq_notify(adapter, eqo->q.id, true, false, 0);

		be_eq_notify(adapter, eqo->q.id, true, false, num_evts);

	} else {

		/* As we'll continue in polling mode, count and clear events */

		be_eq_notify(adapter, eqo->q.id, false, false, events_get(eqo));

		be_eq_notify(adapter, eqo->q.id, false, false, num_evts);

	}

	return max_work;

}