From mboxrd@z Thu Jan 1 00:00:00 1970 From: Or Gerlitz Subject: Re: [PATCH 1/2] mlx4: Expose correct max_sge_rd limit Date: Tue, 27 Oct 2015 16:39:11 +0200 Message-ID: <562F8C8F.8040000@mellanox.com> References: <1445938846-9240-1-git-send-email-sagig@mellanox.com> <1445938846-9240-2-git-send-email-sagig@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1445938846-9240-2-git-send-email-sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sagi Grimberg , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, target-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Steve Wise , "Nicholas A. Bellinger" , Doug Ledford , Yishai Hadas List-Id: linux-rdma@vger.kernel.org On 10/27/2015 11:40 AM, Sagi Grimberg wrote: > mlx4 devices (ConnectX-2, ConnectX-3) can not issue > max_sge in a single RDMA_READ request (resulting in > a completion error). Thus, expose lower max_sge_rd > to avoid this issue. Sagi, I can hear your pain when wearing the iser target driver maintainer hat. Still, this patch is currently pure WA b/c we didn't do RCA (Root Cause Analysis) Lets wait for RCA (which might yield the same patch, BTW) and keep suffering in LIO Or. > > Signed-off-by: Sagi Grimberg > --- > drivers/infiniband/hw/mlx4/main.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c > index 3889723..46305dc 100644 > --- a/drivers/infiniband/hw/mlx4/main.c > +++ b/drivers/infiniband/hw/mlx4/main.c > @@ -499,7 +499,8 @@ static int mlx4_ib_init_device_flags(struct ib_device *ibdev) > ibdev->max_qp_wr = dev->dev->caps.max_wqes - MLX4_IB_SQ_MAX_SPARE; > ibdev->max_sge = min(dev->dev->caps.max_sq_sg, > dev->dev->caps.max_rq_sg); > - ibdev->max_sge_rd = ibdev->max_sge; > + /* reserve 2 sge slots for rdma reads */ > + ibdev->max_sge_rd = ibdev->max_sge - 2; > ibdev->max_cq = dev->dev->quotas.cq; > ibdev->max_cqe = dev->dev->caps.max_cqes; > ibdev->max_mr = dev->dev->quotas.mpt; -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html