Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993221AbbEPINQ (ORCPT ); Sat, 16 May 2015 04:13:16 -0400 Received: from bband-dyn183.178-41-215.t-com.sk ([178.41.215.183]:22719 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2993152AbbEPINI (ORCPT ); Sat, 16 May 2015 04:13:08 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Erez Shitrit , Or Gerlitz , Doug Ledford , Jiri Slaby Subject: [PATCH 3.12 068/142] IB/mlx4: Fix WQE LSO segment calculation Date: Sat, 16 May 2015 09:37:08 +0200 Message-Id: X-Mailer: git-send-email 2.3.7 In-Reply-To: <70c3d4ae1322b9e9bd7443ef574af5635234a0fa.1431761807.git.jslaby@suse.cz> References: <70c3d4ae1322b9e9bd7443ef574af5635234a0fa.1431761807.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2136 Lines: 56 From: Erez Shitrit 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- 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 4f10af2905b5..262a18437ceb 100644 --- a/drivers/infiniband/hw/mlx4/qp.c +++ b/drivers/infiniband/hw/mlx4/qp.c @@ -2174,8 +2174,7 @@ 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; } -- 2.3.7 -- 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/