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ixgbe: Do no clear Tx status bits since eop_desc provides enough info

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There isn't any need to clear the status bits in the descriptors due to the
fact that the eop_desc provides enough information for us to know
that we have cleaned to the last packet that the software has put on the
ring.  The status bits are cleared as a part of putting the frame on the
ring so as long as we do not read the descriptor bit prior to reading the
value eop_desc we should be able to guarantee that we will not clean beyond
the end of the current data stream.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Alexander Duyck 2012-02-08 07:49:23 +00:00 committed by Jeff Kirsher
parent b37c0fbe3f
commit 7f83a9e629
1 changed files with 3 additions and 4 deletions
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7
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
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@ -763,6 +763,9 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_q_vector *q_vector,
if (!eop_desc)
break;
/* prevent any other reads prior to eop_desc */
rmb();
/* if DD is not set pending work has not been completed */
if (!(eop_desc->wb.status & cpu_to_le32(IXGBE_TXD_STAT_DD)))
break;
@ -773,12 +776,8 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_q_vector *q_vector,
/* clear next_to_watch to prevent false hangs */
tx_buffer->next_to_watch = NULL;
/* prevent any other reads prior to eop_desc being verified */
rmb();
do {
ixgbe_unmap_tx_resource(tx_ring, tx_buffer);
tx_desc->wb.status = 0;
if (likely(tx_desc == eop_desc)) {
eop_desc = NULL;
dev_kfree_skb_any(tx_buffer->skb);