[3.13.y-ckt stable] Patch "srp-target: Retry when QP creation fails with ENOMEM" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    srp-target: Retry when QP creation fails with ENOMEM

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 ff111b93d6627dd6d15d5d7a7093550480d166de Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche at acm.org>
Date: Sun, 19 Oct 2014 18:05:33 +0300
Subject: srp-target: Retry when QP creation fails with ENOMEM

commit ab477c1ff5e0a744c072404bf7db51bfe1f05b6e upstream.

It is not guaranteed to that srp_sq_size is supported
by the HCA. So if we failed to create the QP with ENOMEM,
try with a smaller srp_sq_size. Keep it up until we hit
MIN_SRPT_SQ_SIZE, then fail the connection.

Reported-by: Mark Lehrer <lehrer at gmail.com>
Signed-off-by: Bart Van Assche <bvanassche at acm.org>
Signed-off-by: Sagi Grimberg <sagig 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/srpt/ib_srpt.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index b4884ae..97309e4 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -2091,6 +2091,7 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 	if (!qp_init)
 		goto out;

+retry:
 	ch->cq = ib_create_cq(sdev->device, srpt_completion, NULL, ch,
 			      ch->rq_size + srp_sq_size, 0);
 	if (IS_ERR(ch->cq)) {
@@ -2114,6 +2115,13 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 	ch->qp = ib_create_qp(sdev->pd, qp_init);
 	if (IS_ERR(ch->qp)) {
 		ret = PTR_ERR(ch->qp);
+		if (ret == -ENOMEM) {
+			srp_sq_size /= 2;
+			if (srp_sq_size >= MIN_SRPT_SQ_SIZE) {
+				ib_destroy_cq(ch->cq);
+				goto retry;
+			}
+		}
 		printk(KERN_ERR "failed to create_qp ret= %d\n", ret);
 		goto err_destroy_cq;
 	}
--
1.9.1