From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755628AbdKGBKc (ORCPT ); Mon, 6 Nov 2017 20:10:32 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52519 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755237AbdKFXyJ (ORCPT ); Mon, 6 Nov 2017 18:54:09 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Petri Gynther" , "David S. Miller" , "Florian Fainelli" Date: Mon, 06 Nov 2017 23:03:02 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 011/294] net: bcmgenet: simplify __bcmgenet_tx_reclaim() In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.50-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Petri Gynther commit 66d06757d9eb74a29775737b8c770e3b57e536d9 upstream. 1. Use c_index and ring->c_index to determine how many TxCBs/TxBDs are ready for cleanup - c_index = the current value of TDMA_CONS_INDEX - TDMA_CONS_INDEX is HW-incremented and auto-wraparound (0x0-0xFFFF) - ring->c_index = __bcmgenet_tx_reclaim() cleaned up to this point on the previous invocation 2. Add bcmgenet_tx_ring->clean_ptr - index of the next TxCB to be cleaned - incremented as TxCBs/TxBDs are processed - value always in range [ring->cb_ptr, ring->end_ptr] 3. Fix incrementing of dev->stats.tx_packets - should be incremented only when tx_cb_ptr->skb != NULL These changes simplify __bcmgenet_tx_reclaim(). Furthermore, Tx ring size can now be any value. With the old code, Tx ring size had to be a power-of-2: num_tx_bds = ring->size; c_index &= (num_tx_bds - 1); last_c_index &= (num_tx_bds - 1); Signed-off-by: Petri Gynther Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller [bwh: Backported to 3.16: - __bcmgenet_tx_reclaim() did not count completions - In bcmgenet_init_tx_ring(), use write_ptr not start_ptr - Adjust context] Signed-off-by: Ben Hutchings --- --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -946,34 +946,30 @@ static void __bcmgenet_tx_reclaim(struct { struct bcmgenet_priv *priv = netdev_priv(dev); struct device *kdev = &priv->pdev->dev; - int last_tx_cn, last_c_index, num_tx_bds; struct enet_cb *tx_cb_ptr; struct netdev_queue *txq; unsigned int c_index; + unsigned int txbds_ready; + unsigned int txbds_processed = 0; /* Compute how many buffers are transmited since last xmit call */ c_index = bcmgenet_tdma_ring_readl(priv, ring->index, TDMA_CONS_INDEX); - txq = netdev_get_tx_queue(dev, ring->queue); - - last_c_index = ring->c_index; - num_tx_bds = ring->size; + c_index &= DMA_C_INDEX_MASK; - c_index &= (num_tx_bds - 1); - - if (c_index >= last_c_index) - last_tx_cn = c_index - last_c_index; + if (likely(c_index >= ring->c_index)) + txbds_ready = c_index - ring->c_index; else - last_tx_cn = num_tx_bds - last_c_index + c_index; + txbds_ready = (DMA_C_INDEX_MASK + 1) - ring->c_index + c_index; netif_dbg(priv, tx_done, dev, - "%s ring=%d index=%d last_tx_cn=%d last_index=%d\n", - __func__, ring->index, - c_index, last_tx_cn, last_c_index); + "%s ring=%d old_c_index=%u c_index=%u txbds_ready=%u\n", + __func__, ring->index, ring->c_index, c_index, txbds_ready); /* Reclaim transmitted buffers */ - while (last_tx_cn-- > 0) { - tx_cb_ptr = ring->cbs + last_c_index; + while (txbds_processed < txbds_ready) { + tx_cb_ptr = &priv->tx_cbs[ring->clean_ptr]; if (tx_cb_ptr->skb) { + dev->stats.tx_packets++; dev->stats.tx_bytes += tx_cb_ptr->skb->len; dma_unmap_single(kdev, dma_unmap_addr(tx_cb_ptr, dma_addr), @@ -989,20 +985,23 @@ static void __bcmgenet_tx_reclaim(struct DMA_TO_DEVICE); dma_unmap_addr_set(tx_cb_ptr, dma_addr, 0); } - dev->stats.tx_packets++; - ring->free_bds += 1; - last_c_index++; - last_c_index &= (num_tx_bds - 1); + txbds_processed++; + if (likely(ring->clean_ptr < ring->end_ptr)) + ring->clean_ptr++; + else + ring->clean_ptr = ring->cb_ptr; } + ring->free_bds += txbds_processed; + ring->c_index = (ring->c_index + txbds_processed) & DMA_C_INDEX_MASK; + if (ring->free_bds > (MAX_SKB_FRAGS + 1)) ring->int_disable(priv, ring); + txq = netdev_get_tx_queue(dev, ring->queue); if (netif_tx_queue_stopped(txq)) netif_tx_wake_queue(txq); - - ring->c_index = c_index; } static void bcmgenet_tx_reclaim(struct net_device *dev, @@ -1644,6 +1643,7 @@ static void bcmgenet_init_tx_ring(struct } ring->cbs = priv->tx_cbs + write_ptr; ring->size = size; + ring->clean_ptr = write_ptr; ring->c_index = 0; ring->free_bds = size; ring->write_ptr = write_ptr; --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.h +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.h @@ -510,6 +510,7 @@ struct bcmgenet_tx_ring { unsigned int queue; /* queue index */ struct enet_cb *cbs; /* tx ring buffer control block*/ unsigned int size; /* size of each tx ring */ + unsigned int clean_ptr; /* Tx ring clean pointer */ unsigned int c_index; /* last consumer index of each ring*/ unsigned int free_bds; /* # of free bds for each ring */ unsigned int write_ptr; /* Tx ring write pointer SW copy */