From: Logan Gunthorpe <logang@deltatee.com>
To: linux-ntb@googlegroups.com, linux-kernel@vger.kernel.org
Cc: Jon Mason <jdmason@kudzu.us>, Dave Jiang <dave.jiang@intel.com>,
Allen Hubbe <Allen.Hubbe@emc.com>
Subject: Re: [PATCH] ntb_transport: fix qp count bug
Date: Fri, 8 Dec 2017 17:02:07 -0700 [thread overview]
Message-ID: <205eb69f-9c1c-5391-7145-6cb15a670649@deltatee.com> (raw)
In-Reply-To: <20171209000106.18259-2-logang@deltatee.com>
Sorry, ignore this. I sent an old patch.
Logan
On 08/12/17 05:01 PM, Logan Gunthorpe wrote:
> In cases where there are more mw's than spads/2-2, the mw count gets
> reduced to match the limitation. ntb_transport also tries to ensure that
> there are fewer qps than mws but uses the full mw count instead of
> the reduced one. When this happens, the math in
> 'ntb_transport_setup_qp_mw' will get confused and result in a kernel
> paging request bug.
>
> This patch fixes the bug by reducing qp_count to the reduced mw count
> instead of the full mw count.
>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> Cc: Jon Mason <jdmason@kudzu.us>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Allen Hubbe <Allen.Hubbe@emc.com>
> ---
> drivers/ntb/ntb_transport.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
> index 02ca45fdd892..0a778d2cab94 100644
> --- a/drivers/ntb/ntb_transport.c
> +++ b/drivers/ntb/ntb_transport.c
> @@ -1128,8 +1128,8 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
> qp_count = ilog2(qp_bitmap);
> if (max_num_clients && max_num_clients < qp_count)
> qp_count = max_num_clients;
> - else if (mw_count < qp_count)
> - qp_count = mw_count;
> + else if (nt->mw_count < qp_count)
> + qp_count = nt->mw_count;
>
> qp_bitmap &= BIT_ULL(qp_count) - 1;
>
>
next prev parent reply other threads:[~2017-12-09 0:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-09 0:01 [PATCH] ntb_netdev: set the net_device's parent Logan Gunthorpe
2017-12-09 0:01 ` [PATCH] ntb_transport: fix qp count bug Logan Gunthorpe
2017-12-09 0:02 ` Logan Gunthorpe [this message]
2017-12-09 0:01 ` [PATCH] ntb_netdev: set the net_device's parent Logan Gunthorpe
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