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cxgb4: Avoids race and deadlock while freeing tx descriptor

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There could be race between t4_eth_xmit() and t4_free_sge_resources() while
freeing tx descriptors, take txq lock in t4_free_sge_resources(). We need
to stop the xmit frame path which runs in bottom half context while
unloading the driver using _bh variant of the lock. This is to prevent
the deadlock between xmit and driver unload.

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Hariprasad Shenai 2016-04-26 20:10:24 +05:30 committed by David S. Miller
parent ed98c85ee9
commit fbe8077687
1 changed files with 2 additions and 0 deletions
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2
drivers/net/ethernet/chelsio/cxgb4/sge.c
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@ -3006,7 +3006,9 @@ void t4_free_sge_resources(struct adapter *adap)
if (etq->q.desc) {
t4_eth_eq_free(adap, adap->mbox, adap->pf, 0,
etq->q.cntxt_id);
__netif_tx_lock_bh(etq->txq);
free_tx_desc(adap, &etq->q, etq->q.in_use, true);
__netif_tx_unlock_bh(etq->txq);
kfree(etq->q.sdesc);
free_txq(adap, &etq->q);
}