From 071ba4cc559de47160761b9500b72e8fa09d923d Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Mon, 26 Oct 2020 11:25:49 -0300 Subject: RDMA: Add rdma_connect_locked() There are two flows for handling RDMA_CM_EVENT_ROUTE_RESOLVED, either the handler triggers a completion and another thread does rdma_connect() or the handler directly calls rdma_connect(). In all cases rdma_connect() needs to hold the handler_mutex, but when handler's are invoked this is already held by the core code. This causes ULPs using the 2nd method to deadlock. Provide a rdma_connect_locked() and have all ULPs call it from their handlers. Link: https://lore.kernel.org/r/0-v2-53c22d5c1405+33-rdma_connect_locking_jgg@nvidia.com Reported-and-tested-by: Guoqing Jiang Fixes: 2a7cec538169 ("RDMA/cma: Fix locking for the RDMA_CM_CONNECT state") Acked-by: Santosh Shilimkar Acked-by: Jack Wang Reviewed-by: Christoph Hellwig Reviewed-by: Max Gurtovoy Reviewed-by: Sagi Grimberg Signed-off-by: Jason Gunthorpe --- include/rdma/rdma_cm.h | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) (limited to 'include/rdma') diff --git a/include/rdma/rdma_cm.h b/include/rdma/rdma_cm.h index c672ae1da26b..32a67af18415 100644 --- a/include/rdma/rdma_cm.h +++ b/include/rdma/rdma_cm.h @@ -227,19 +227,9 @@ void rdma_destroy_qp(struct rdma_cm_id *id); int rdma_init_qp_attr(struct rdma_cm_id *id, struct ib_qp_attr *qp_attr, int *qp_attr_mask); -/** - * rdma_connect - Initiate an active connection request. - * @id: Connection identifier to connect. - * @conn_param: Connection information used for connected QPs. - * - * Users must have resolved a route for the rdma_cm_id to connect with - * by having called rdma_resolve_route before calling this routine. - * - * This call will either connect to a remote QP or obtain remote QP - * information for unconnected rdma_cm_id's. The actual operation is - * based on the rdma_cm_id's port space. - */ int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param); +int rdma_connect_locked(struct rdma_cm_id *id, + struct rdma_conn_param *conn_param); int rdma_connect_ece(struct rdma_cm_id *id, struct rdma_conn_param *conn_param, struct rdma_ucm_ece *ece); -- cgit