From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Subject: [PATCH net-next 04/27] net: mvpp2: release reference to txq_cpu[] entry after unmapping Date: Wed, 21 Dec 2016 12:16:11 +0100 Message-ID: <1482318994-23488-5-git-send-email-thomas.petazzoni@free-electrons.com> References: <1482318994-23488-1-git-send-email-thomas.petazzoni@free-electrons.com> Cc: Nadav Haklai , Hanna Hawa , Yehuda Yitschak , Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Gregory Clement , linux-arm-kernel@lists.infradead.org, Stefan Chulski , Marcin Wojtas , Thomas Petazzoni To: "David S. Miller" , netdev@vger.kernel.org Return-path: Received: from mail.free-electrons.com ([62.4.15.54]:56087 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750795AbcLULQk (ORCPT ); Wed, 21 Dec 2016 06:16:40 -0500 In-Reply-To: <1482318994-23488-1-git-send-email-thomas.petazzoni@free-electrons.com> Sender: netdev-owner@vger.kernel.org List-ID: The mvpp2_txq_bufs_free() function is called upon TX completion to DMA unmap TX buffers, and free the corresponding SKBs. It gets the references to the SKB to free and the DMA buffer to unmap from a per-CPU txq_pcpu data structure. However, the code currently increments the pointer to the next entry before doing the DMA unmap and freeing the SKB. It does not cause any visible problem because for a given SKB the TX completion is guaranteed to take place on the CPU where the TX was started. However, it is much more logical to increment the pointer to the next entry once the current entry has been completely unmapped/released. Signed-off-by: Thomas Petazzoni --- drivers/net/ethernet/marvell/mvpp2.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/marvell/mvpp2.c b/drivers/net/ethernet/marvell/mvpp2.c index 12edefe..84eb5fb 100644 --- a/drivers/net/ethernet/marvell/mvpp2.c +++ b/drivers/net/ethernet/marvell/mvpp2.c @@ -4420,13 +4420,12 @@ static void mvpp2_txq_bufs_free(struct mvpp2_port *port, struct mvpp2_txq_pcpu_buf *tx_buf = txq_pcpu->buffs + txq_pcpu->txq_get_index; - mvpp2_txq_inc_get(txq_pcpu); - dma_unmap_single(port->dev->dev.parent, tx_buf->phys, tx_buf->size, DMA_TO_DEVICE); - if (!tx_buf->skb) - continue; - dev_kfree_skb_any(tx_buf->skb); + if (tx_buf->skb) + dev_kfree_skb_any(tx_buf->skb); + + mvpp2_txq_inc_get(txq_pcpu); } } -- 2.7.4