From: Venkatesh Srinivas <[email protected]> e1000 writes to doorbells to post transmit descriptors and fill the receive ring. After writing descriptors to memory but before writing to doorbells, use dma_wmb() rather than wmb(). wmb() is more heavyweight than necessary for a device to see descriptor writes.
On x86, this avoids SFENCEs before doorbell writes in both the Tx and Rx paths. On ARM, this converts DSB ST -> DMB OSHST. Tested: 82576EB / x86; QEMU (qemu emulates an 8257x) Signed-off-by: Venkatesh Srinivas <[email protected]> Tested-by: Aaron Brown <[email protected]> Signed-off-by: Jeff Kirsher <[email protected]> --- drivers/net/ethernet/intel/e1000/e1000_main.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c index 551de8c2fef2..f703fa58458e 100644 --- a/drivers/net/ethernet/intel/e1000/e1000_main.c +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c @@ -3019,7 +3019,7 @@ static void e1000_tx_queue(struct e1000_adapter *adapter, * applicable for weak-ordered memory model archs, * such as IA-64). */ - wmb(); + dma_wmb(); tx_ring->next_to_use = i; } @@ -4540,7 +4540,7 @@ e1000_alloc_jumbo_rx_buffers(struct e1000_adapter *adapter, * applicable for weak-ordered memory model archs, * such as IA-64). */ - wmb(); + dma_wmb(); writel(i, adapter->hw.hw_addr + rx_ring->rdt); } } @@ -4655,7 +4655,7 @@ static void e1000_alloc_rx_buffers(struct e1000_adapter *adapter, * applicable for weak-ordered memory model archs, * such as IA-64). */ - wmb(); + dma_wmb(); writel(i, hw->hw_addr + rx_ring->rdt); } } -- 2.21.0
