This is a note to let you know that I've just added the patch titled
IB/mlx4: Fix WQE LSO segment calculation
to the 4.0-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:
ib-mlx4-fix-wqe-lso-segment-calculation.patch
and it can be found in the queue-4.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ca9b590caa17bcbbea119594992666e96cde9c2f Mon Sep 17 00:00:00 2001
From: Erez Shitrit <erezsh@xxxxxxxxxxxx>
Date: Thu, 2 Apr 2015 13:39:05 +0300
Subject: IB/mlx4: Fix WQE LSO segment calculation
From: Erez Shitrit <erezsh@xxxxxxxxxxxx>
commit ca9b590caa17bcbbea119594992666e96cde9c2f upstream.
The current code decreases from the mss size (which is the gso_size
from the kernel skb) the size of the packet headers.
It shouldn't do that because the mss that comes from the stack
(e.g IPoIB) includes only the tcp payload without the headers.
The result is indication to the HW that each packet that the HW sends
is smaller than what it could be, and too many packets will be sent
for big messages.
An easy way to demonstrate one more aspect of the problem is by
configuring the ipoib mtu to be less than 2*hlen (2*56) and then
run app sending big TCP messages. This will tell the HW to send packets
with giant (negative value which under unsigned arithmetics becomes
a huge positive one) length and the QP moves to SQE state.
Fixes: b832be1e4007 ('IB/mlx4: Add IPoIB LSO support')
Reported-by: Matthew Finlay <matt@xxxxxxxxxxxx>
Signed-off-by: Erez Shitrit <erezsh@xxxxxxxxxxxx>
Signed-off-by: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/hw/mlx4/qp.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c
@@ -2605,8 +2605,7 @@ static int build_lso_seg(struct mlx4_wqe
memcpy(wqe->header, wr->wr.ud.header, wr->wr.ud.hlen);
- *lso_hdr_sz = cpu_to_be32((wr->wr.ud.mss - wr->wr.ud.hlen) << 16 |
- wr->wr.ud.hlen);
+ *lso_hdr_sz = cpu_to_be32(wr->wr.ud.mss << 16 | wr->wr.ud.hlen);
*lso_seg_len = halign;
return 0;
}
Patches currently in stable-queue which might be from erezsh@xxxxxxxxxxxx are
queue-4.0/ib-mlx4-fix-wqe-lso-segment-calculation.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html