RDMA/qedr: Fix synchronization methods and memory leaks in qedr

Re-design of the iWARP CM related objects reference counting and
synchronization methods, to ensure operations are synchronized correctly
and that memory allocated for "ep" is properly released. Also makes sure
QP memory is not released before ep is finished accessing it.

Where as the QP object is created/destroyed by external operations, the ep
is created/destroyed by internal operations and represents the tcp
connection associated with the QP.

QP destruction flow:
- needs to wait for ep establishment to complete (either successfully or
  with error)
- needs to wait for ep disconnect to be fully posted to avoid a race
  condition of disconnect being called after reset.
- both the operations above don't always happen, so we use atomic flags to
  indicate whether the qp destruction flow needs to wait for these
  completions or not, if the destroy is called before these operations
  began, the flows will check the flags and not execute them ( connect /
  disconnect).

We use completion structure for waiting for the completions mentioned
above.

The QP refcnt was modified to kref object.  The EP has a kref added to it
to handle additional worker thread accessing it.

Memory Leaks - https://www.spinics.net/lists/linux-rdma/msg83762.html

Concurrency not managed correctly -
https://www.spinics.net/lists/linux-rdma/msg67949.html

Fixes: de0089e692a9 ("RDMA/qedr: Add iWARP connection management qp related callbacks")
Link: https://lore.kernel.org/r/20191027200451.28187-4-michal.kalderon@marvell.com
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Reported-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Ariel Elior <ariel.elior@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 19 insertions, 4 deletions

diff --git a/drivers/infiniband/hw/qedr/qedr.h b/drivers/infiniband/hw/qedr/qedr.h
index 0cfd849b13d6..8e927f6c1520 100644
--- a/drivers/infiniband/hw/qedr/qedr.h
+++ b/drivers/infiniband/hw/qedr/qedr.h
@@ -40,6 +40,7 @@
 #include <linux/qed/qed_rdma_if.h>
 #include <linux/qed/qede_rdma.h>
 #include <linux/qed/roce_common.h>
+#include <linux/completion.h>
 #include "qedr_hsi_rdma.h"
 
 #define QEDR_NODE_DESC "QLogic 579xx RoCE HCA"
@@ -377,10 +378,20 @@ enum qedr_qp_err_bitmap {
 	QEDR_QP_ERR_RQ_PBL_FULL = 32,
 };
 
+enum qedr_qp_create_type {
+	QEDR_QP_CREATE_NONE,
+	QEDR_QP_CREATE_USER,
+	QEDR_QP_CREATE_KERNEL,
+};
+
+enum qedr_iwarp_cm_flags {
+	QEDR_IWARP_CM_WAIT_FOR_CONNECT    = BIT(0),
+	QEDR_IWARP_CM_WAIT_FOR_DISCONNECT = BIT(1),
+};
+
 struct qedr_qp {
 	struct ib_qp ibqp;	/* must be first */
 	struct qedr_dev *dev;
-	struct qedr_iw_ep *ep;
 	struct qedr_qp_hwq_info sq;
 	struct qedr_qp_hwq_info rq;
 
@@ -395,6 +406,7 @@ struct qedr_qp {
 	u32 id;
 	struct qedr_pd *pd;
 	enum ib_qp_type qp_type;
+	enum qedr_qp_create_type create_type;
 	struct qed_rdma_qp *qed_qp;
 	u32 qp_id;
 	u16 icid;
@@ -437,8 +449,11 @@ struct qedr_qp {
 	/* Relevant to qps created from user space only (applications) */
 	struct qedr_userq usq;
 	struct qedr_userq urq;
-	atomic_t refcnt;
-	bool destroyed;
+
+	/* synchronization objects used with iwarp ep */
+	struct kref refcnt;
+	struct completion iwarp_cm_comp;
+	unsigned long iwarp_cm_flags; /* enum iwarp_cm_flags */
 };
 
 struct qedr_ah {
@@ -531,7 +546,7 @@ struct qedr_iw_ep {
 	struct iw_cm_id	*cm_id;
 	struct qedr_qp	*qp;
 	void		*qed_context;
-	u8		during_connect;
+	struct kref	refcnt;
 };
 
 static inline