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[RFC,v1,2/7] net/ena: relax the barrier for doorbell ring

Message ID 20200313091835.58039-3-gavin.hu@arm.com (mailing list archive)
State RFC, archived
Delegated to: Ferruh Yigit
Headers show
Series relax barriers for ENA PMD and small fixes | expand

Checks

Context Check Description
ci/Intel-compilation fail Compilation issues
ci/checkpatch success coding style OK

Commit Message

Gavin Hu March 13, 2020, 9:18 a.m. UTC
rte_cio_wmb is a light weight version of IO memory barrier that
guarantees that the stores to the coherent memory prior to the
the rte_cio_rmb() call are visible to the NIC HW before the doorbell
ring(or any other stores to the MMIO registers) that follows it.[1]

Fixes: 5e02e19eb14e ("net/ena: fix unneeded doorbell submission")
Cc: stable@dpdk.org

[1] http://code.dpdk.org/dpdk/v20.02/source/lib/librte_eal/common/
include/generic/rte_atomic.h#L137

Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
---
 drivers/net/ena/ena_ethdev.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
index 665afee4f..c268788fd 100644
--- a/drivers/net/ena/ena_ethdev.c
+++ b/drivers/net/ena/ena_ethdev.c
@@ -1425,7 +1425,7 @@  static int ena_populate_rx_queue(struct ena_ring *rxq, unsigned int count)
 		 * Add memory barrier to make sure the desc were written before
 		 * issue a doorbell
 		 */
-		rte_wmb();
+		rte_cio_wmb();
 		ena_com_write_sq_doorbell(rxq->ena_com_io_sq);
 
 		rxq->next_to_use = next_to_use;
@@ -2344,7 +2344,7 @@  static uint16_t eth_ena_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 			PMD_DRV_LOG(DEBUG, "llq tx max burst size of queue %d"
 				" achieved, writing doorbell to send burst\n",
 				tx_ring->id);
-			rte_wmb();
+			rte_cio_wmb();
 			ena_com_write_sq_doorbell(tx_ring->ena_com_io_sq);
 		}
 
@@ -2367,7 +2367,7 @@  static uint16_t eth_ena_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 	/* If there are ready packets to be xmitted... */
 	if (sent_idx > 0) {
 		/* ...let HW do its best :-) */
-		rte_wmb();
+		rte_cio_wmb();
 		ena_com_write_sq_doorbell(tx_ring->ena_com_io_sq);
 		tx_ring->tx_stats.doorbells++;
 		tx_ring->next_to_use = next_to_use;