[PATCH for-next v6 8/8] RDMA/rxe: Add wait for completion to obj destruct

[Bob Pearson <rpearsonhpe@gmail.com>]

This patch adds code to wait until pending activity on RDMA objects has
completed before freeing or returning to rdma-core where the object may
be freed.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
v6
  Corrected incorrect comment before __rxe_fini()
  Added a #define for complete timeout value.
  Changed type of __rxe_fini to int to return value from wait_for_completion.
---
 drivers/infiniband/sw/rxe/rxe_comp.c  |  4 +-
 drivers/infiniband/sw/rxe/rxe_mcast.c |  4 ++
 drivers/infiniband/sw/rxe/rxe_mr.c    |  2 +
 drivers/infiniband/sw/rxe/rxe_mw.c    | 14 +++--
 drivers/infiniband/sw/rxe/rxe_pool.c  | 31 +++++++++-
 drivers/infiniband/sw/rxe/rxe_pool.h  |  4 ++
 drivers/infiniband/sw/rxe/rxe_recv.c  |  4 +-
 drivers/infiniband/sw/rxe/rxe_req.c   | 11 ++--
 drivers/infiniband/sw/rxe/rxe_resp.c  |  6 +-
 drivers/infiniband/sw/rxe/rxe_verbs.c | 84 ++++++++++++++++++++-------
 10 files changed, 126 insertions(+), 38 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c
index f363fe3fa414..a2bb66f320fa 100644
--- a/drivers/infiniband/sw/rxe/rxe_comp.c
+++ b/drivers/infiniband/sw/rxe/rxe_comp.c
@@ -562,7 +562,9 @@ int rxe_completer(void *arg)
 	enum comp_state state;
 	int ret = 0;
 
-	rxe_add_ref(qp);
+	/* check qp pointer still valid */
+	if (!rxe_add_ref(qp))
+		return -EAGAIN;
 
 	if (!qp->valid || qp->req.state == QP_STATE_ERROR ||
 	    qp->req.state == QP_STATE_RESET) {
diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c b/drivers/infiniband/sw/rxe/rxe_mcast.c
index b935634f86cd..70d48f5847b0 100644
--- a/drivers/infiniband/sw/rxe/rxe_mcast.c
+++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
@@ -122,6 +122,8 @@ int rxe_mcast_drop_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
 
 out_drop_ref:
 	rxe_drop_ref(grp);			/* ref from get_key */
+	if (grp->elem.complete.done)
+		rxe_fini(grp);
 err1:
 	return ret;
 }
@@ -149,6 +151,8 @@ void rxe_drop_all_mcast_groups(struct rxe_qp *qp)
 		spin_unlock_bh(&grp->mcg_lock);
 		rxe_drop_ref(qp);
 		rxe_drop_ref(grp);
+		if (grp->elem.complete.done)
+			rxe_fini(grp);
 		kfree(elem);
 	}
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 3c4390adfb80..5f8c08da352d 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -695,6 +695,8 @@ int rxe_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
 	rxe_drop_ref(mr_pd(mr));
 	rxe_drop_ref(mr);
 
+	rxe_fini(mr);
+
 	return 0;
 }
 
diff --git a/drivers/infiniband/sw/rxe/rxe_mw.c b/drivers/infiniband/sw/rxe/rxe_mw.c
index 3ae981d77c25..9b3468911976 100644
--- a/drivers/infiniband/sw/rxe/rxe_mw.c
+++ b/drivers/infiniband/sw/rxe/rxe_mw.c
@@ -12,7 +12,8 @@ int rxe_alloc_mw(struct ib_mw *ibmw, struct ib_udata *udata)
 	struct rxe_dev *rxe = to_rdev(ibmw->device);
 	int ret;
 
-	rxe_add_ref(pd);
+	if (!rxe_add_ref(pd))
+		return -EINVAL;
 
 	ret = rxe_add_to_pool(&rxe->mw_pool, mw);
 	if (ret) {
@@ -60,8 +61,9 @@ int rxe_dealloc_mw(struct ib_mw *ibmw)
 	rxe_do_dealloc_mw(mw);
 	spin_unlock_bh(&mw->lock);
 
-	rxe_drop_ref(mw);
 	rxe_drop_ref(pd);
+	rxe_drop_ref(mw);
+	rxe_fini(mw);
 
 	return 0;
 }
@@ -178,11 +180,11 @@ static void rxe_do_bind_mw(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 	if (mw->length) {
 		mw->mr = mr;
 		atomic_inc(&mr->num_mw);
-		rxe_add_ref(mr);
+		rxe_add_ref(mr);	/* safe */
 	}
 
 	if (mw->ibmw.type == IB_MW_TYPE_2) {
-		rxe_add_ref(qp);
+		rxe_add_ref(qp);	/* safe */
 		mw->qp = qp;
 	}
 }
@@ -199,7 +201,7 @@ int rxe_bind_mw(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
 	mw = rxe_pool_get_index(&rxe->mw_pool, mw_rkey >> 8);
 	if (unlikely(!mw)) {
 		ret = -EINVAL;
-		goto err;
+		goto err_out;
 	}
 
 	if (unlikely(mw->rkey != mw_rkey)) {
@@ -236,7 +238,7 @@ int rxe_bind_mw(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
 		rxe_drop_ref(mr);
 err_drop_mw:
 	rxe_drop_ref(mw);
-err:
+err_out:
 	return ret;
 }
 
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index ff03d1f9d92e..10a14c575487 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -6,6 +6,8 @@
 
 #include "rxe.h"
 
+/* timeout in jiffies for pool element to complete */
+#define RXE_POOL_TIMEOUT	(100)
 #define RXE_POOL_ALIGN		(16)
 
 static const struct rxe_type_info {
@@ -150,6 +152,7 @@ static void *__rxe_alloc(struct rxe_pool *pool, gfp_t flags)
 	elem->pool = pool;
 	elem->obj = obj;
 	kref_init(&elem->ref_cnt);
+	init_completion(&elem->complete);
 
 	if (pool->init) {
 		err = pool->init(elem);
@@ -189,6 +192,7 @@ int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_elem *elem)
 	elem->pool = pool;
 	elem->obj = (u8 *)elem - pool->elem_offset;
 	kref_init(&elem->ref_cnt);
+	init_completion(&elem->complete);
 
 	if (pool->init) {
 		err = pool->init(elem);
@@ -375,8 +379,33 @@ void rxe_elem_release(struct kref *kref)
 	if (pool->cleanup)
 		pool->cleanup(elem);
 
+	atomic_dec(&pool->num_elem);
+
+	complete(&elem->complete);
+}
+
+/**
+ * __rxe_fini() - wait for completion of pool element
+ * @elem: the pool elem
+ *
+ * Wait until the reference count of an object drops to zero when
+ * rxe_elem_release() will complete the object and then, if locally
+ * allocated, free the memory containing the object and return
+ *
+ * Returns: non-zero if the object completed successfully else zero
+ */
+int __rxe_fini(struct rxe_pool_elem *elem)
+{
+	struct rxe_pool *pool = elem->pool;
+	int ret;
+
+	ret = wait_for_completion_timeout(&elem->complete, RXE_POOL_TIMEOUT);
+	if (!ret)
+		pr_warn_ratelimited("Timed out waiting for %s#%d to complete\n",
+				pool->name, elem->index);
+
 	if (pool->flags & RXE_POOL_ALLOC)
 		kfree(elem->obj);
 
-	atomic_dec(&pool->num_elem);
+	return ret;
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.h b/drivers/infiniband/sw/rxe/rxe_pool.h
index db2caff6f408..1f94601087f8 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.h
+++ b/drivers/infiniband/sw/rxe/rxe_pool.h
@@ -30,6 +30,7 @@ struct rxe_pool_elem {
 	struct rxe_pool		*pool;
 	void			*obj;
 	struct kref		ref_cnt;
+	struct completion	complete;
 	struct list_head	list;
 
 	/* only used if keyed */
@@ -105,4 +106,7 @@ static inline bool __rxe_drop_ref(struct rxe_pool_elem *elem)
 }
 #define rxe_drop_ref(obj) __rxe_drop_ref(&(obj)->elem)
 
+int __rxe_fini(struct rxe_pool_elem *elem);
+#define rxe_fini(obj) __rxe_fini(&(obj)->elem)
+
 #endif /* RXE_POOL_H */
diff --git a/drivers/infiniband/sw/rxe/rxe_recv.c b/drivers/infiniband/sw/rxe/rxe_recv.c
index 6a6cc1fa90e4..4c7077aec9a7 100644
--- a/drivers/infiniband/sw/rxe/rxe_recv.c
+++ b/drivers/infiniband/sw/rxe/rxe_recv.c
@@ -288,11 +288,11 @@ static void rxe_rcv_mcast_pkt(struct rxe_dev *rxe, struct sk_buff *skb)
 
 			cpkt = SKB_TO_PKT(cskb);
 			cpkt->qp = qp;
-			rxe_add_ref(qp);
+			rxe_add_ref(qp);	/* safe */
 			rxe_rcv_pkt(cpkt, cskb);
 		} else {
 			pkt->qp = qp;
-			rxe_add_ref(qp);
+			rxe_add_ref(qp);	/* safe */
 			rxe_rcv_pkt(pkt, skb);
 			skb = NULL;	/* mark consumed */
 		}
diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
index 7bc1ec8a5aa6..9b75515cd0f4 100644
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -614,9 +614,10 @@ int rxe_requester(void *arg)
 	struct rxe_ah *ah;
 	struct rxe_av *av;
 
-	rxe_add_ref(qp);
+	/* check qp pointer still valid */
+	if (!rxe_add_ref(qp))
+		return -EAGAIN;
 
-next_wqe:
 	if (unlikely(!qp->valid || qp->req.state == QP_STATE_ERROR))
 		goto exit;
 
@@ -644,7 +645,7 @@ int rxe_requester(void *arg)
 		if (unlikely(ret))
 			goto err;
 		else
-			goto next_wqe;
+			goto done;
 	}
 
 	if (unlikely(qp_type(qp) == IB_QPT_RC &&
@@ -760,7 +761,9 @@ int rxe_requester(void *arg)
 
 	update_state(qp, wqe, &pkt, payload);
 
-	goto next_wqe;
+done:
+	rxe_drop_ref(qp);
+	return 0;
 
 err_drop_ah:
 	if (ah)
diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index c776289842e5..5aaf4573c0ac 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -463,8 +463,8 @@ static enum resp_states check_rkey(struct rxe_qp *qp,
 		if (mw->access & IB_ZERO_BASED)
 			qp->resp.offset = mw->addr;
 
+		rxe_add_ref(mr);	/* safe */
 		rxe_drop_ref(mw);
-		rxe_add_ref(mr);
 	} else {
 		mr = lookup_mr(qp->pd, access, rkey, RXE_LOOKUP_REMOTE);
 		if (!mr) {
@@ -1247,7 +1247,9 @@ int rxe_responder(void *arg)
 	struct rxe_pkt_info *pkt = NULL;
 	int ret = 0;
 
-	rxe_add_ref(qp);
+	/* check qp pointer still valid */
+	if (!rxe_add_ref(qp))
+		return -EAGAIN;
 
 	qp->resp.aeth_syndrome = AETH_ACK_UNLIMITED;
 
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index e3f64eae088c..06b508ba4e2d 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -116,6 +116,7 @@ static void rxe_dealloc_ucontext(struct ib_ucontext *ibuc)
 	struct rxe_ucontext *uc = to_ruc(ibuc);
 
 	rxe_drop_ref(uc);
+	rxe_fini(uc);
 }
 
 static int rxe_port_immutable(struct ib_device *dev, u32 port_num,
@@ -150,6 +151,7 @@ static int rxe_dealloc_pd(struct ib_pd *ibpd, struct ib_udata *udata)
 	struct rxe_pd *pd = to_rpd(ibpd);
 
 	rxe_drop_ref(pd);
+	rxe_fini(pd);
 	return 0;
 }
 
@@ -189,6 +191,7 @@ static int rxe_create_ah(struct ib_ah *ibah,
 					 sizeof(uresp->ah_num));
 		if (err) {
 			rxe_drop_ref(ah);
+			rxe_fini(ah);
 			return -EFAULT;
 		}
 	} else if (ah->is_user) {
@@ -229,6 +232,7 @@ static int rxe_destroy_ah(struct ib_ah *ibah, u32 flags)
 	struct rxe_ah *ah = to_rah(ibah);
 
 	rxe_drop_ref(ah);
+	rxe_fini(ah);
 	return 0;
 }
 
@@ -297,25 +301,29 @@ static int rxe_create_srq(struct ib_srq *ibsrq, struct ib_srq_init_attr *init,
 
 	err = rxe_srq_chk_attr(rxe, NULL, &init->attr, IB_SRQ_INIT_MASK);
 	if (err)
-		goto err1;
+		goto err_out;
 
 	err = rxe_add_to_pool(&rxe->srq_pool, srq);
 	if (err)
-		goto err1;
+		goto err_out;
+
+	if (!rxe_add_ref(pd))
+		goto err_drop_srq;
 
-	rxe_add_ref(pd);
 	srq->pd = pd;
 
 	err = rxe_srq_from_init(rxe, srq, init, udata, uresp);
 	if (err)
-		goto err2;
+		goto err_drop_pd;
 
 	return 0;
 
-err2:
+err_drop_pd:
 	rxe_drop_ref(pd);
+err_drop_srq:
 	rxe_drop_ref(srq);
-err1:
+	rxe_fini(srq);
+err_out:
 	return err;
 }
 
@@ -373,6 +381,7 @@ static int rxe_destroy_srq(struct ib_srq *ibsrq, struct ib_udata *udata)
 
 	rxe_drop_ref(srq->pd);
 	rxe_drop_ref(srq);
+	rxe_fini(srq);
 	return 0;
 }
 
@@ -442,6 +451,7 @@ static int rxe_create_qp(struct ib_qp *ibqp, struct ib_qp_init_attr *init,
 
 qp_init:
 	rxe_drop_ref(qp);
+	rxe_fini(qp);
 	return err;
 }
 
@@ -486,6 +496,7 @@ static int rxe_destroy_qp(struct ib_qp *ibqp, struct ib_udata *udata)
 
 	rxe_qp_destroy(qp);
 	rxe_drop_ref(qp);
+	rxe_fini(qp);
 	return 0;
 }
 
@@ -797,6 +808,7 @@ static int rxe_destroy_cq(struct ib_cq *ibcq, struct ib_udata *udata)
 	rxe_cq_disable(cq);
 
 	rxe_drop_ref(cq);
+	rxe_fini(cq);
 	return 0;
 }
 
@@ -882,15 +894,28 @@ static struct ib_mr *rxe_get_dma_mr(struct ib_pd *ibpd, int access)
 	struct rxe_dev *rxe = to_rdev(ibpd->device);
 	struct rxe_pd *pd = to_rpd(ibpd);
 	struct rxe_mr *mr;
+	int err;
 
 	mr = rxe_alloc(&rxe->mr_pool);
-	if (!mr)
-		return ERR_PTR(-ENOMEM);
+	if (!mr) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+
+	if (!rxe_add_ref(pd)) {
+		err = -EINVAL;
+		goto err_drop_mr;
+	}
 
-	rxe_add_ref(pd);
 	rxe_mr_init_dma(pd, access, mr);
 
 	return &mr->ibmr;
+
+err_drop_mr:
+	rxe_drop_ref(mr);
+	rxe_fini(mr);
+err_out:
+	return ERR_PTR(err);
 }
 
 static struct ib_mr *rxe_reg_user_mr(struct ib_pd *ibpd,
@@ -899,30 +924,35 @@ static struct ib_mr *rxe_reg_user_mr(struct ib_pd *ibpd,
 				     u64 iova,
 				     int access, struct ib_udata *udata)
 {
-	int err;
 	struct rxe_dev *rxe = to_rdev(ibpd->device);
 	struct rxe_pd *pd = to_rpd(ibpd);
 	struct rxe_mr *mr;
+	int err;
 
 	mr = rxe_alloc(&rxe->mr_pool);
 	if (!mr) {
 		err = -ENOMEM;
-		goto err2;
+		goto err_out;
 	}
 
 
-	rxe_add_ref(pd);
+	if (!rxe_add_ref(pd)) {
+		err = -EINVAL;
+		goto err_drop_mr;
+	}
 
 	err = rxe_mr_init_user(pd, start, length, iova, access, mr);
 	if (err)
-		goto err3;
+		goto err_drop_pd;
 
 	return &mr->ibmr;
 
-err3:
+err_drop_pd:
 	rxe_drop_ref(pd);
+err_drop_mr:
 	rxe_drop_ref(mr);
-err2:
+	rxe_fini(mr);
+err_out:
 	return ERR_PTR(err);
 }
 
@@ -934,27 +964,34 @@ static struct ib_mr *rxe_alloc_mr(struct ib_pd *ibpd, enum ib_mr_type mr_type,
 	struct rxe_mr *mr;
 	int err;
 
-	if (mr_type != IB_MR_TYPE_MEM_REG)
-		return ERR_PTR(-EINVAL);
+	if (mr_type != IB_MR_TYPE_MEM_REG) {
+		err = -EINVAL;
+		goto err_out;
+	}
 
 	mr = rxe_alloc(&rxe->mr_pool);
 	if (!mr) {
 		err = -ENOMEM;
-		goto err1;
+		goto err_out;
 	}
 
-	rxe_add_ref(pd);
+	if (!rxe_add_ref(pd)) {
+		err = -EINVAL;
+		goto err_drop_mr;
+	}
 
 	err = rxe_mr_init_fast(pd, max_num_sg, mr);
 	if (err)
-		goto err2;
+		goto err_drop_pd;
 
 	return &mr->ibmr;
 
-err2:
+err_drop_pd:
 	rxe_drop_ref(pd);
+err_drop_mr:
 	rxe_drop_ref(mr);
-err1:
+	rxe_fini(mr);
+err_out:
 	return ERR_PTR(err);
 }
 
@@ -994,8 +1031,10 @@ static int rxe_attach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
 	if (err)
 		return err;
 
+	/* adds a ref on grp if successful */
 	err = rxe_mcast_add_grp_elem(rxe, qp, grp);
 
+	/* drops the ref from ..get_grp() */
 	rxe_drop_ref(grp);
 	return err;
 }
@@ -1005,6 +1044,7 @@ static int rxe_detach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
 	struct rxe_dev *rxe = to_rdev(ibqp->device);
 	struct rxe_qp *qp = to_rqp(ibqp);
 
+	/* drops a ref on grp if successful */
 	return rxe_mcast_drop_grp_elem(rxe, qp, mgid);
 }
 
-- 
2.32.0