[Intel-wired-lan] [next PATCH v2 2/9] igb: Use length to determine if descriptor is done
Alexander Duyck
alexander.duyck at gmail.com
Tue Jan 17 16:31:48 UTC 2017
From: Alexander Duyck <alexander.h.duyck at intel.com>
This change makes it so that we use the length of the packet instead of the
DD status bit to determine if a new descriptor is ready to be processed.
The obvious advantage is that it cuts down on reads as we don't really even
need the DD bit if going from a 0 to a non-zero value on size is enough to
inform us that the packet has been completed.
In addition I have updated the code so that we only reset the Rx descriptor
length for descriptor zero when resetting a ring instead of having to do a
memset with 0 over the entire ring. By doing this we can save some time on
initialization.
Signed-off-by: Alexander Duyck <alexander.h.duyck at intel.com>
---
v2: Update ethtool loopback test to use length check instead of DD check
drivers/net/ethernet/intel/igb/igb_ethtool.c | 2 +-
drivers/net/ethernet/intel/igb/igb_main.c | 14 ++++++++------
2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
index 737b664d004c..3f5f7744c90f 100644
--- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
+++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
@@ -1811,7 +1811,7 @@ static int igb_clean_test_rings(struct igb_ring *rx_ring,
tx_ntc = tx_ring->next_to_clean;
rx_desc = IGB_RX_DESC(rx_ring, rx_ntc);
- while (igb_test_staterr(rx_desc, E1000_RXD_STAT_DD)) {
+ while (rx_desc->wb.upper.length) {
/* check Rx buffer */
rx_buffer_info = &rx_ring->rx_buffer_info[rx_ntc];
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index eede6db6037c..91a524b155ce 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -3720,6 +3720,7 @@ void igb_configure_rx_ring(struct igb_adapter *adapter,
struct igb_ring *ring)
{
struct e1000_hw *hw = &adapter->hw;
+ union e1000_adv_rx_desc *rx_desc;
u64 rdba = ring->dma;
int reg_idx = ring->reg_idx;
u32 srrctl = 0, rxdctl = 0;
@@ -3758,6 +3759,10 @@ void igb_configure_rx_ring(struct igb_adapter *adapter,
rxdctl |= IGB_RX_HTHRESH << 8;
rxdctl |= IGB_RX_WTHRESH << 16;
+ /* initialize Rx descriptor 0 */
+ rx_desc = IGB_RX_DESC(ring, 0);
+ rx_desc->wb.upper.length = 0;
+
/* enable receive descriptor fetching */
rxdctl |= E1000_RXDCTL_QUEUE_ENABLE;
wr32(E1000_RXDCTL(reg_idx), rxdctl);
@@ -3973,9 +3978,6 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring)
size = sizeof(struct igb_rx_buffer) * rx_ring->count;
memset(rx_ring->rx_buffer_info, 0, size);
- /* Zero out the descriptor ring */
- memset(rx_ring->desc, 0, rx_ring->size);
-
rx_ring->next_to_alloc = 0;
rx_ring->next_to_clean = 0;
rx_ring->next_to_use = 0;
@@ -7174,7 +7176,7 @@ static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
rx_desc = IGB_RX_DESC(rx_ring, rx_ring->next_to_clean);
- if (!rx_desc->wb.upper.status_error)
+ if (!rx_desc->wb.upper.length)
break;
/* This memory barrier is needed to keep us from reading
@@ -7314,8 +7316,8 @@ void igb_alloc_rx_buffers(struct igb_ring *rx_ring, u16 cleaned_count)
i -= rx_ring->count;
}
- /* clear the status bits for the next_to_use descriptor */
- rx_desc->wb.upper.status_error = 0;
+ /* clear the length for the next_to_use descriptor */
+ rx_desc->wb.upper.length = 0;
cleaned_count--;
} while (cleaned_count);
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