[PATCH net-next] bnx2x: Resolving a possible dead-lock situation

Vladislav Zolotarov
2010-11-23T16:15:49Z

There is a possible dead-lock situation between sch_direct_xmit()
(called from soft_IRQ context) and bnx2x_tx_int() when called from
an ethtool self-test flow (syscall context).

To prevent a dead-lock, disable bottom-halves on a local CPU when taking
a tx_lock from bnx2x_tx_int() (use __netif_tx_lock_bh(txq)).

The flow in the bnx2x_tx_int() where tx_lock is taken should be hit
very rarely thus performance penalty of this change should be minimal.

Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
---
drivers/net/bnx2x/bnx2x_cmn.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bnx2x/bnx2x_cmn.c b/drivers/net/bnx2x/bnx2x_cmn.c
index 94d5f59..5189788 100644
--- a/drivers/net/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/bnx2x/bnx2x_cmn.c
@@ -144,14 +144,14 @@ int bnx2x_tx_int(struct bnx2x_fastpath *fp)
* stops the queue
*/

- __netif_tx_lock(txq, smp_processor_id());
+ __netif_tx_lock_bh(txq);

if ((netif_tx_queue_stopped(txq)) &&
(bp->state == BNX2X_STATE_OPEN) &&
(bnx2x_tx_avail(fp) >= MAX_SKB_FRAGS + 3))
netif_tx_wake_queue(txq);

- __netif_tx_unlock(txq);
+ __netif_tx_unlock_bh(txq);
}
return 0;
}
--
1.7.0.4