From: Sameeh Jubran Date: Mon, 3 Jun 2019 17:43:27 +0300 Subject: [PATCH] net: ena: optimise calculations for CQ doorbell Origin: https://git.kernel.org/linus/d91860989dd4bce582ed6c3647a0d41d6fd895b3 Bug-Debian: https://bugs.debian.org/941291 This patch initially checks if CQ doorbell is needed before proceeding with the calculations. Signed-off-by: Igor Chauskin Signed-off-by: Sameeh Jubran Signed-off-by: David S. Miller --- drivers/net/ethernet/amazon/ena/ena_eth_com.h | 20 ++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_eth_com.h b/drivers/net/ethernet/amazon/ena/ena_eth_com.h index 0a3d9180e40e..77986c0ea52c 100644 --- a/drivers/net/ethernet/amazon/ena/ena_eth_com.h +++ b/drivers/net/ethernet/amazon/ena/ena_eth_com.h @@ -195,15 +195,17 @@ static inline int ena_com_update_dev_comp_head(struct ena_com_io_cq *io_cq) u16 unreported_comp, head; bool need_update; - head = io_cq->head; - unreported_comp = head - io_cq->last_head_update; - need_update = unreported_comp > (io_cq->q_depth / ENA_COMP_HEAD_THRESH); - - if (io_cq->cq_head_db_reg && need_update) { - pr_debug("Write completion queue doorbell for queue %d: head: %d\n", - io_cq->qid, head); - writel(head, io_cq->cq_head_db_reg); - io_cq->last_head_update = head; + if (unlikely(io_cq->cq_head_db_reg)) { + head = io_cq->head; + unreported_comp = head - io_cq->last_head_update; + need_update = unreported_comp > (io_cq->q_depth / ENA_COMP_HEAD_THRESH); + + if (unlikely(need_update)) { + pr_debug("Write completion queue doorbell for queue %d: head: %d\n", + io_cq->qid, head); + writel(head, io_cq->cq_head_db_reg); + io_cq->last_head_update = head; + } } return 0; -- 2.17.1