From: Venkatesh Srinivas <venkate...@google.com>
igb writes to doorbells to post transmit and receive descriptors;
after writing descriptors to memory but before writing to doorbells,
use dma_wmb() rather than wmb(). wmb() is more heavyweight than
necessary before doorbell writes.
On x86, this avoids SFENCEs before doorbell writes in both the
tx and rx refill paths.
Signed-off-by: Venkatesh Srinivas <venkate...@google.com>
Tested-by: Aaron Brown <aaron.f.br...@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirs...@intel.com>
---
drivers/net/ethernet/intel/igb/igb_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c
b/drivers/net/ethernet/intel/igb/igb_main.c
index e3a0c02721c9..25720d95d4ea 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6031,7 +6031,7 @@ static int igb_tx_map(struct igb_ring *tx_ring,
* We also need this memory barrier to make certain all of the
* status bits have been updated before next_to_watch is written.
*/
- wmb();
+ dma_wmb();
/* set next_to_watch value indicating a packet is present */
first->next_to_watch = tx_desc;
@@ -8531,7 +8531,7 @@ void igb_alloc_rx_buffers(struct igb_ring *rx_ring, u16
cleaned_count)
* applicable for weak-ordered memory model archs,
* such as IA-64).
*/
- wmb();
+ dma_wmb();
writel(i, rx_ring->tail);
}
}
--
2.17.1
