linux_dsm_epyc7002/drivers/net/ethernet/google
Liran Alon b54ef37b1c net: Google gve: Remove dma_wmb() before ringing doorbell
Current code use dma_wmb() to ensure Rx/Tx descriptors are visible
to device before writing to doorbell.

However, these dma_wmb() are wrong and unnecessary. Therefore,
they should be removed.

iowrite32be() called from gve_rx_write_doorbell()/gve_tx_put_doorbell()
should guaratee that all previous writes to WB/UC memory is visible to
device before the write done by iowrite32be().

E.g. On ARM64, iowrite32be() calls __iowmb() which expands to dma_wmb()
and only then calls __raw_writel().

Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-03 12:40:53 -08:00
..
gve net: Google gve: Remove dma_wmb() before ringing doorbell 2020-01-03 12:40:53 -08:00
Kconfig gve: Add basic driver framework for Compute Engine Virtual NIC 2019-07-01 19:36:35 -07:00
Makefile gve: Add basic driver framework for Compute Engine Virtual NIC 2019-07-01 19:36:35 -07:00