From: Emil Tantilov <emil.s.tantilov@intel.com>
Date: Mon, 11 Dec 2017 10:36:59 -0800
Subject: ixgbevf: use length to determine if descriptor is done
Patch-mainline: v4.16-rc1
Git-commit: 24bff091d7691c162580bcdb57bb00015471d34e
References: bsc#1101674 FATE#325150 FATE#325151
Based on:
commit 7ec0116c9131 ("igb: Use length to determine if descriptor is done")
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 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: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -653,8 +653,8 @@ static void ixgbevf_alloc_rx_buffers(str
i -= rx_ring->count;
}
- /* clear the hdr_addr for the next_to_use descriptor */
- rx_desc->read.hdr_addr = 0;
+ /* clear the length for the next_to_use descriptor */
+ rx_desc->wb.upper.length = 0;
cleaned_count--;
} while (cleaned_count);
@@ -938,7 +938,7 @@ static int ixgbevf_clean_rx_irq(struct i
rx_desc = IXGBEVF_RX_DESC(rx_ring, rx_ring->next_to_clean);
- if (!ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_DD))
+ if (!rx_desc->wb.upper.length)
break;
/* This memory barrier is needed to keep us from reading
@@ -1729,6 +1729,7 @@ static void ixgbevf_configure_rx_ring(st
struct ixgbevf_ring *ring)
{
struct ixgbe_hw *hw = &adapter->hw;
+ union ixgbe_adv_rx_desc *rx_desc;
u64 rdba = ring->dma;
u32 rxdctl;
u8 reg_idx = ring->reg_idx;
@@ -1757,6 +1758,10 @@ static void ixgbevf_configure_rx_ring(st
IXGBE_WRITE_REG(hw, IXGBE_VFRDT(reg_idx), 0);
ring->tail = adapter->io_addr + IXGBE_VFRDT(reg_idx);
+ /* initialize Rx descriptor 0 */
+ rx_desc = IXGBEVF_RX_DESC(ring, 0);
+ rx_desc->wb.upper.length = 0;
+
/* reset ntu and ntc to place SW in sync with hardwdare */
ring->next_to_clean = 0;
ring->next_to_use = 0;
@@ -2141,9 +2146,6 @@ static void ixgbevf_clean_rx_ring(struct
size = sizeof(struct ixgbevf_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);
}
/**