srp-target: Retry when QP creation fails with ENOMEM

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@gmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # 3.4+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 7206547c13ce0dc8dda59458658d843d64520327..dc829682701ad1dbae8375eb2ff9a2c97feea48f 100644 (file)
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -2092,6 +2092,7 @@ 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)) {
@@ -2115,6 +2116,13 @@ 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;
        }