LU-12678 o2iblnd: allocate init_qp_attr on stack.

'struct ib_qp_init_attr' is not so large that it cannot be allocated
on the stack.  It is about 100 bytes, various other function in Linux
allocate it on the stack, and the stack isn't as constrained as it
once was.

So allocate on stack instead of using kmalloc and handling errors.

Test-Parameters: trivial testlist=sanity-lnet
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: Id1f2f695f298d1883a5d6817092a6f89f1e072ef
Reviewed-on: https://review.whamcloud.com/39122
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lnet/klnds/o2iblnd/o2iblnd.c b/lnet/klnds/o2iblnd/o2iblnd.c
index 4678424..54968f4 100644 (file)
--- a/lnet/klnds/o2iblnd/o2iblnd.c
+++ b/lnet/klnds/o2iblnd/o2iblnd.c
@@ -773,7 +773,7 @@ kiblnd_create_conn(struct kib_peer_ni *peer_ni, struct rdma_cm_id *cmid,
        rwlock_t               *glock = &kiblnd_data.kib_global_lock;
        struct kib_net              *net = peer_ni->ibp_ni->ni_data;
        struct kib_dev *dev;
-       struct ib_qp_init_attr *init_qp_attr;
+       struct ib_qp_init_attr init_qp_attr = {};
        struct kib_sched_info   *sched;
 #ifdef HAVE_IB_CQ_INIT_ATTR
        struct ib_cq_init_attr  cq_attr = {};
@@ -804,19 +804,11 @@ kiblnd_create_conn(struct kib_peer_ni *peer_ni, struct rdma_cm_id *cmid,
         */
        cpt = sched->ibs_cpt;
 
-       LIBCFS_CPT_ALLOC(init_qp_attr, lnet_cpt_table(), cpt,
-                        sizeof(*init_qp_attr));
-       if (init_qp_attr == NULL) {
-               CERROR("Can't allocate qp_attr for %s\n",
-                      libcfs_nid2str(peer_ni->ibp_nid));
-               goto failed_0;
-       }
-
        LIBCFS_CPT_ALLOC(conn, lnet_cpt_table(), cpt, sizeof(*conn));
        if (conn == NULL) {
                CERROR("Can't allocate connection for %s\n",
                       libcfs_nid2str(peer_ni->ibp_nid));
-               goto failed_1;
+               goto failed_0;
        }
 
        conn->ibc_state = IBLND_CONN_INIT;
@@ -905,29 +897,29 @@ kiblnd_create_conn(struct kib_peer_ni *peer_ni, struct rdma_cm_id *cmid,
                goto failed_2;
        }
 
-       init_qp_attr->event_handler = kiblnd_qp_event;
-       init_qp_attr->qp_context = conn;
-       init_qp_attr->cap.max_send_sge = *kiblnd_tunables.kib_wrq_sge;
-       init_qp_attr->cap.max_recv_sge = 1;
-       init_qp_attr->sq_sig_type = IB_SIGNAL_REQ_WR;
-       init_qp_attr->qp_type = IB_QPT_RC;
-       init_qp_attr->send_cq = cq;
-       init_qp_attr->recv_cq = cq;
+       init_qp_attr.event_handler = kiblnd_qp_event;
+       init_qp_attr.qp_context = conn;
+       init_qp_attr.cap.max_send_sge = *kiblnd_tunables.kib_wrq_sge;
+       init_qp_attr.cap.max_recv_sge = 1;
+       init_qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
+       init_qp_attr.qp_type = IB_QPT_RC;
+       init_qp_attr.send_cq = cq;
+       init_qp_attr.recv_cq = cq;
        /*
         * kiblnd_send_wrs() can change the connection's queue depth if
         * the maximum work requests for the device is maxed out
         */
-       init_qp_attr->cap.max_send_wr = kiblnd_send_wrs(conn);
-       init_qp_attr->cap.max_recv_wr = IBLND_RECV_WRS(conn);
+       init_qp_attr.cap.max_send_wr = kiblnd_send_wrs(conn);
+       init_qp_attr.cap.max_recv_wr = IBLND_RECV_WRS(conn);
 
-       rc = rdma_create_qp(cmid, conn->ibc_hdev->ibh_pd, init_qp_attr);
+       rc = rdma_create_qp(cmid, conn->ibc_hdev->ibh_pd, &init_qp_attr);
        if (rc) {
                CERROR("Can't create QP: %d, send_wr: %d, recv_wr: %d, "
                       "send_sge: %d, recv_sge: %d\n",
-                      rc, init_qp_attr->cap.max_send_wr,
-                      init_qp_attr->cap.max_recv_wr,
-                      init_qp_attr->cap.max_send_sge,
-                      init_qp_attr->cap.max_recv_sge);
+                      rc, init_qp_attr.cap.max_send_wr,
+                      init_qp_attr.cap.max_recv_wr,
+                      init_qp_attr.cap.max_send_sge,
+                      init_qp_attr.cap.max_recv_sge);
                goto failed_2;
        }
 
@@ -954,8 +946,6 @@ kiblnd_create_conn(struct kib_peer_ni *peer_ni, struct rdma_cm_id *cmid,
 
        kiblnd_map_rx_descs(conn);
 
-       LIBCFS_FREE(init_qp_attr, sizeof(*init_qp_attr));
-
        /* 1 ref for caller and each rxmsg */
        atomic_set(&conn->ibc_refcount, 1 + IBLND_RX_MSGS(conn));
        conn->ibc_nrx = IBLND_RX_MSGS(conn);
@@ -1001,8 +991,6 @@ kiblnd_create_conn(struct kib_peer_ni *peer_ni, struct rdma_cm_id *cmid,
  failed_2:
        kiblnd_destroy_conn(conn);
        LIBCFS_FREE(conn, sizeof(*conn));
- failed_1:
-        LIBCFS_FREE(init_qp_attr, sizeof(*init_qp_attr));
  failed_0:
         return NULL;
 }