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authorLogan Gunthorpe <logang@deltatee.com>2017-06-05 14:00:53 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-30 10:19:29 +0200
commit4e5f2c2041503bd0f855b9467de3cd05a8748c91 (patch)
tree0a31ca69d7a759270963b43c895aa6153e449e34 /drivers
parent1aac8ffd619f893b93cbd4c28abe43ecee7f82ef (diff)
downloadlinux-linaro-stable-4e5f2c2041503bd0f855b9467de3cd05a8748c91.tar.gz
ntb_transport: fix bug calculating num_qps_mw
commit 8e8496e0e9564b66165f5219a4e8ed20b0d3fc6b upstream. A divide by zero error occurs if qp_count is less than mw_count because num_qps_mw is calculated to be zero. The calculation appears to be incorrect. The requirement is for num_qps_mw to be set to qp_count / mw_count with any remainder divided among the earlier mws. For example, if mw_count is 5 and qp_count is 12 then mws 0 and 1 will have 3 qps per window and mws 2 through 4 will have 2 qps per window. Thus, when mw_num < qp_count % mw_count, num_qps_mw is 1 higher than when mw_num >= qp_count. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Fixes: e26a5843f7f5 ("NTB: Split ntb_hw_intel and ntb_transport drivers") Acked-by: Allen Hubbe <Allen.Hubbe@dell.com> Signed-off-by: Jon Mason <jdmason@kudzu.us> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/ntb/ntb_transport.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 1c02a48a7e99..3bbdf60f8908 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -599,7 +599,7 @@ static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
if (!mw->virt_addr)
return -ENOMEM;
- if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
+ if (mw_num < qp_count % mw_count)
num_qps_mw = qp_count / mw_count + 1;
else
num_qps_mw = qp_count / mw_count;
@@ -947,7 +947,7 @@ static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
qp->event_handler = NULL;
ntb_qp_link_down_reset(qp);
- if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
+ if (mw_num < qp_count % mw_count)
num_qps_mw = qp_count / mw_count + 1;
else
num_qps_mw = qp_count / mw_count;