This is a note to let you know that I've just added the patch titled
ntb_transport: fix bug calculating num_qps_mw
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ntb_transport-fix-bug-calculating-num_qps_mw.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8e8496e0e9564b66165f5219a4e8ed20b0d3fc6b Mon Sep 17 00:00:00 2001
From: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Date: Mon, 5 Jun 2017 14:00:53 -0600
Subject: ntb_transport: fix bug calculating num_qps_mw
From: Logan Gunthorpe <logang@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Fixes: e26a5843f7f5 ("NTB: Split ntb_hw_intel and ntb_transport drivers")
Acked-by: Allen Hubbe <Allen.Hubbe@xxxxxxxx>
Signed-off-by: Jon Mason <jdmason@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/ntb/ntb_transport.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -625,7 +625,7 @@ static int ntb_transport_setup_qp_mw(str
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;
@@ -1002,7 +1002,7 @@ static int ntb_transport_init_queue(stru
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;
Patches currently in stable-queue which might be from logang@xxxxxxxxxxxx are
queue-4.9/ntb-ntb_test-fix-bug-printing-ntb_perf-results.patch
queue-4.9/ntb_transport-fix-bug-calculating-num_qps_mw.patch
queue-4.9/ntb-ntb_test-ensure-the-link-is-up-before-trying-to-configure-the-mws.patch
queue-4.9/ntb_transport-fix-qp-count-bug.patch