[3.13.y-ckt stable] Patch "ib_isert: Add max_send_sge=2 minimum for control PDU responses" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Tue Dec 2 19:03:10 UTC 2014
This is a note to let you know that I have just added a patch titled
ib_isert: Add max_send_sge=2 minimum for control PDU responses
to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue
This patch is scheduled to be released in version 3.13.11-ckt12.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From f8c9d7a0509b1a5c3b60303ccd48f95457570ecb Mon Sep 17 00:00:00 2001
From: Or Gerlitz <ogerlitz at mellanox.com>
Date: Wed, 22 Oct 2014 14:55:49 -0700
Subject: ib_isert: Add max_send_sge=2 minimum for control PDU responses
commit f57915cfa5b2b14c1cffa2e83c034f55e3f0e70d upstream.
This patch adds a max_send_sge=2 minimum in isert_conn_setup_qp()
to ensure outgoing control PDU responses with tx_desc->num_sge=2
are able to function correctly.
This addresses a bug with RDMA hardware using dev_attr.max_sge=3,
that in the original code with the ConnectX-2 work-around would
result in isert_conn->max_sge=1 being negotiated.
Originally reported by Chris with ocrdma driver.
Reported-by: Chris Moore <Chris.Moore at emulex.com>
Tested-by: Chris Moore <Chris.Moore at emulex.com>
Signed-off-by: Or Gerlitz <ogerlitz at mellanox.com>
Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
drivers/infiniband/ulp/isert/ib_isert.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 9b2a108..708ca27 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -112,9 +112,12 @@ isert_conn_setup_qp(struct isert_conn *isert_conn, struct rdma_cm_id *cma_id)
attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS;
/*
* FIXME: Use devattr.max_sge - 2 for max_send_sge as
- * work-around for RDMA_READ..
+ * work-around for RDMA_READs with ConnectX-2.
+ *
+ * Also, still make sure to have at least two SGEs for
+ * outgoing control PDU responses.
*/
- attr.cap.max_send_sge = device->dev_attr.max_sge - 2;
+ attr.cap.max_send_sge = max(2, device->dev_attr.max_sge - 2);
isert_conn->max_sge = attr.cap.max_send_sge;
attr.cap.max_recv_sge = 1;
--
1.9.1
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