Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753457AbbEGJ6J (ORCPT ); Thu, 7 May 2015 05:58:09 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:48227 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753045AbbEGJuO (ORCPT ); Thu, 7 May 2015 05:50:14 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Erez Shitrit , Or Gerlitz , Doug Ledford , Luis Henriques Subject: [PATCH 3.16.y-ckt 166/180] IB/mlx4: Fix WQE LSO segment calculation Date: Thu, 7 May 2015 10:46:15 +0100 Message-Id: <1430991989-23170-167-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1430991989-23170-1-git-send-email-luis.henriques@canonical.com> References: <1430991989-23170-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2155 Lines: 53 3.16.7-ckt11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Erez Shitrit commit ca9b590caa17bcbbea119594992666e96cde9c2f upstream. The current code decreases from the mss size (which is the gso_size from the kernel skb) the size of the packet headers. It shouldn't do that because the mss that comes from the stack (e.g IPoIB) includes only the tcp payload without the headers. The result is indication to the HW that each packet that the HW sends is smaller than what it could be, and too many packets will be sent for big messages. An easy way to demonstrate one more aspect of the problem is by configuring the ipoib mtu to be less than 2*hlen (2*56) and then run app sending big TCP messages. This will tell the HW to send packets with giant (negative value which under unsigned arithmetics becomes a huge positive one) length and the QP moves to SQE state. Fixes: b832be1e4007 ('IB/mlx4: Add IPoIB LSO support') Reported-by: Matthew Finlay Signed-off-by: Erez Shitrit Signed-off-by: Or Gerlitz Signed-off-by: Doug Ledford Signed-off-by: Luis Henriques --- drivers/infiniband/hw/mlx4/qp.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c index 67780452f0cf..6914462e4b5b 100644 --- a/drivers/infiniband/hw/mlx4/qp.c +++ b/drivers/infiniband/hw/mlx4/qp.c @@ -2535,8 +2535,7 @@ static int build_lso_seg(struct mlx4_wqe_lso_seg *wqe, struct ib_send_wr *wr, memcpy(wqe->header, wr->wr.ud.header, wr->wr.ud.hlen); - *lso_hdr_sz = cpu_to_be32((wr->wr.ud.mss - wr->wr.ud.hlen) << 16 | - wr->wr.ud.hlen); + *lso_hdr_sz = cpu_to_be32(wr->wr.ud.mss << 16 | wr->wr.ud.hlen); *lso_seg_len = halign; return 0; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/