Return-Path: Received: from ale.deltatee.com (ale.deltatee.com. [207.54.116.67]) by gmr-mx.google.com with ESMTPS id b9si514990pff.4.2017.12.08.16.01.29 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 08 Dec 2017 16:01:29 -0800 (PST) From: Logan Gunthorpe Date: Fri, 8 Dec 2017 17:01:05 -0700 Message-Id: <20171209000106.18259-2-logang@deltatee.com> In-Reply-To: <20171209000106.18259-1-logang@deltatee.com> References: <20171209000106.18259-1-logang@deltatee.com> Subject: [PATCH] ntb_transport: fix qp count bug To: linux-ntb@googlegroups.com, linux-kernel@vger.kernel.org Cc: Logan Gunthorpe , Jon Mason , Dave Jiang , Allen Hubbe List-ID: 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 Cc: Jon Mason Cc: Dave Jiang Cc: Allen Hubbe --- 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; -- 2.11.0