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ixgbevf: Check if EOP has changed before using it

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There is a chance that between the time EOP is read and the time it is
used another transmit on a different CPU could have run and completed,
thus leaving EOP in a bad state.

Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Greg Rose 2011-06-03 03:53:24 +00:00 committed by Jeff Kirsher
parent dc22129471
commit 98b9e48fca
1 changed files with 4 additions and 0 deletions
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4
drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
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@ -203,6 +203,9 @@ static bool ixgbevf_clean_tx_irq(struct ixgbevf_adapter *adapter,
(count < tx_ring->work_limit)) {
bool cleaned = false;
rmb(); /* read buffer_info after eop_desc */
/* eop could change between read and DD-check */
if (unlikely(eop != tx_ring->tx_buffer_info[i].next_to_watch))
goto cont_loop;
for ( ; !cleaned; count++) {
struct sk_buff *skb;
tx_desc = IXGBE_TX_DESC_ADV(*tx_ring, i);
@ -232,6 +235,7 @@ static bool ixgbevf_clean_tx_irq(struct ixgbevf_adapter *adapter,
i = 0;
}
cont_loop:
eop = tx_ring->tx_buffer_info[i].next_to_watch;
eop_desc = IXGBE_TX_DESC_ADV(*tx_ring, eop);
}