IB/cm: Avoid AV ah_attr overwriting during LAP message handling

AH attribute of the cm_id can be overwritten if LAP message is received
on CM request which is in progress. This bug got introduced to avoid
sleeping when spin lock is held as part of commit in Fixes tag.

Therefore validate the cm_id state first and continue to perform AV
ah_attr initialization.

Given that Aleternative path related messages are not supported for
RoCE, init_av_from_response/path is such messages are ok to be called
from blocking context.

Fixes: 33f93e1ebcf5 ("IB/cm: Fix sleeping while spin lock is held")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index a92e1a5c202b3605c971adca6fde9c944af71852..34b4defc3d1fa66d49fadaf2a896c173a4ffd8be 100644 (file)
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -3189,12 +3189,6 @@ static int cm_lap_handler(struct cm_work *work)
        if (!cm_id_priv)
                return -EINVAL;
 
-       ret = cm_init_av_for_response(work->port, work->mad_recv_wc->wc,
-                                     work->mad_recv_wc->recv_buf.grh,
-                                     &cm_id_priv->av);
-       if (ret)
-               goto deref;
-
        param = &work->cm_event.param.lap_rcvd;
        memset(&work->path[0], 0, sizeof(work->path[1]));
        cm_path_set_rec_type(work->port->cm_dev->ib_device,
@@ -3239,10 +3233,16 @@ static int cm_lap_handler(struct cm_work *work)
                goto unlock;
        }
 
-       cm_id_priv->id.lap_state = IB_CM_LAP_RCVD;
-       cm_id_priv->tid = lap_msg->hdr.tid;
+       ret = cm_init_av_for_response(work->port, work->mad_recv_wc->wc,
+                                     work->mad_recv_wc->recv_buf.grh,
+                                     &cm_id_priv->av);
+       if (ret)
+               goto unlock;
+
        cm_init_av_by_path(param->alternate_path, &cm_id_priv->alt_av,
                           cm_id_priv);
+       cm_id_priv->id.lap_state = IB_CM_LAP_RCVD;
+       cm_id_priv->tid = lap_msg->hdr.tid;
        ret = atomic_inc_and_test(&cm_id_priv->work_count);
        if (!ret)
                list_add_tail(&work->list, &cm_id_priv->work_list);