From patchwork Wed Dec 28 16:45:59 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Petazzoni X-Patchwork-Id: 9490535 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B9DA560838 for ; Wed, 28 Dec 2016 16:50:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 81AD020144 for ; Wed, 28 Dec 2016 16:50:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7605626538; Wed, 28 Dec 2016 16:50:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 1412720144 for ; Wed, 28 Dec 2016 16:50:17 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1cMHO1-0001ya-V9; Wed, 28 Dec 2016 16:47:33 +0000 Received: from mail.free-electrons.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1cMHNI-0001qK-GN for linux-arm-kernel@lists.infradead.org; Wed, 28 Dec 2016 16:46:52 +0000 Received: by mail.free-electrons.com (Postfix, from userid 110) id A8BCB2076D; Wed, 28 Dec 2016 17:46:23 +0100 (CET) Received: from localhost (LStLambert-657-1-97-87.w90-63.abo.wanadoo.fr [90.63.216.87]) by mail.free-electrons.com (Postfix) with ESMTPSA id 7F41420767; Wed, 28 Dec 2016 17:46:23 +0100 (CET) From: Thomas Petazzoni To: netdev@vger.kernel.org, "David S. Miller" Subject: [PATCHv2 net-next 03/11] net: mvpp2: release reference to txq_cpu[] entry after unmapping Date: Wed, 28 Dec 2016 17:45:59 +0100 Message-Id: <1482943567-12483-4-git-send-email-thomas.petazzoni@free-electrons.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1482943567-12483-1-git-send-email-thomas.petazzoni@free-electrons.com> References: <1482943567-12483-1-git-send-email-thomas.petazzoni@free-electrons.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161228_084648_893952_8EA0906C X-CRM114-Status: GOOD ( 11.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Petazzoni , Andrew Lunn , Yehuda Yitschak , Jason Cooper , Hanna Hawa , Nadav Haklai , Gregory Clement , Stefan Chulski , Marcin Wojtas , linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 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 a1ba89f..d098c7b 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); } }