RDMA/restrack: Count references to the verbs objects

Refactor the restrack code to make sure the kref inside the restrack entry
properly kref's the object in which it is embedded. This slight change is
needed for future conversions of MR and QP which are refcounted before the
release and kfree.

The ideal flow from ib_core perspective as follows:
* Allocate ib_* structure with rdma_zalloc_*.
* Set everything that is known to ib_core to that newly created object.
* Initialize kref with restrack help
* Call to driver specific allocation functions.
* Insert into restrack DB
....
* Return and release restrack with restrack_put.

Largely this means a rdma_restrack_new() should be called near allocating
the containing structure.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

Author: Leon Romanovsky

drivers/infiniband/core/cma.c

@@ -833,8 +833,6 @@ struct rdma_cm_id *__rdma_create_id(struct net *net,
 	if (!id_priv)
 		return ERR_PTR(-ENOMEM);
 
-	rdma_restrack_set_task(&id_priv->res, caller);
-	id_priv->res.type = RDMA_RESTRACK_CM_ID;
 	id_priv->state = RDMA_CM_IDLE;
 	id_priv->id.context = context;
 	id_priv->id.event_handler = event_handler;
@@ -854,6 +852,9 @@ struct rdma_cm_id *__rdma_create_id(struct net *net,
 	id_priv->id.route.addr.dev_addr.net = get_net(net);
 	id_priv->seq_num &= 0x00ffffff;
 
+	rdma_restrack_new(&id_priv->res, RDMA_RESTRACK_CM_ID);
+	rdma_restrack_set_task(&id_priv->res, caller);
+
 	return &id_priv->id;
 }
 EXPORT_SYMBOL(__rdma_create_id);

drivers/infiniband/core/core_priv.h

@@ -44,6 +44,7 @@
 #include <rdma/ib_mad.h>
 #include <rdma/restrack.h>
 #include "mad_priv.h"
+#include "restrack.h"
 
 /* Total number of ports combined across all struct ib_devices's */
 #define RDMA_MAX_PORTS 8192
@@ -352,14 +353,14 @@ static inline struct ib_qp *_ib_create_qp(struct ib_device *dev,
 	INIT_LIST_HEAD(&qp->rdma_mrs);
 	INIT_LIST_HEAD(&qp->sig_mrs);
 
+	rdma_restrack_new(&qp->res, RDMA_RESTRACK_QP);
 	/*
 	 * We don't track XRC QPs for now, because they don't have PD
 	 * and more importantly they are created internaly by driver,
 	 * see mlx5 create_dev_resources() as an example.
 	 */
 	is_xrc = qp_type == IB_QPT_XRC_INI || qp_type == IB_QPT_XRC_TGT;
 	if ((qp_type < IB_QPT_MAX && !is_xrc) || qp_type == IB_QPT_DRIVER) {
-		qp->res.type = RDMA_RESTRACK_QP;
 		if (uobj)
 			rdma_restrack_uadd(&qp->res);
 		else

drivers/infiniband/core/counters.c

@@ -80,8 +80,9 @@ static struct rdma_counter *rdma_counter_alloc(struct ib_device *dev, u8 port,
 
 	counter->device    = dev;
 	counter->port      = port;
-	counter->res.type  = RDMA_RESTRACK_COUNTER;
-	counter->stats     = dev->ops.counter_alloc_stats(counter);
+
+	rdma_restrack_new(&counter->res, RDMA_RESTRACK_COUNTER);
+	counter->stats = dev->ops.counter_alloc_stats(counter);
 	if (!counter->stats)
 		goto err_stats;
 
@@ -107,6 +108,7 @@ static struct rdma_counter *rdma_counter_alloc(struct ib_device *dev, u8 port,
 	mutex_unlock(&port_counter->lock);
 	kfree(counter->stats);
 err_stats:
+	rdma_restrack_put(&counter->res);
 	kfree(counter);
 	return NULL;
 }

drivers/infiniband/core/cq.c

@@ -235,15 +235,13 @@ struct ib_cq *__ib_alloc_cq(struct ib_device *dev, void *private, int nr_cqe,
 	if (!cq->wc)
 		goto out_free_cq;
 
-	cq->res.type = RDMA_RESTRACK_CQ;
+	rdma_restrack_new(&cq->res, RDMA_RESTRACK_CQ);
 	rdma_restrack_set_task(&cq->res, caller);
 
 	ret = dev->ops.create_cq(cq, &cq_attr, NULL);
 	if (ret)
 		goto out_free_wc;
 
-	rdma_restrack_kadd(&cq->res);
-
 	rdma_dim_init(cq);
 
 	switch (cq->poll_ctx) {
@@ -269,14 +267,15 @@ struct ib_cq *__ib_alloc_cq(struct ib_device *dev, void *private, int nr_cqe,
 		goto out_destroy_cq;
 	}
 
+	rdma_restrack_kadd(&cq->res);
 	trace_cq_alloc(cq, nr_cqe, comp_vector, poll_ctx);
 	return cq;
 
 out_destroy_cq:
 	rdma_dim_destroy(cq);
-	rdma_restrack_del(&cq->res);
 	cq->device->ops.destroy_cq(cq, NULL);
 out_free_wc:
+	rdma_restrack_put(&cq->res);
 	kfree(cq->wc);
 out_free_cq:
 	kfree(cq);

drivers/infiniband/core/restrack.c

@@ -202,6 +202,21 @@ void rdma_restrack_attach_task(struct rdma_restrack_entry *res,
 	res->task = task;
 }
 
+/**
+ * rdma_restrack_new() - Initializes new restrack entry to allow _put() interface
+ * to release memory in fully automatic way.
+ * @res - Entry to initialize
+ * @type - REstrack type
+ */
+void rdma_restrack_new(struct rdma_restrack_entry *res,
+		       enum rdma_restrack_type type)
+{
+	kref_init(&res->kref);
+	init_completion(&res->comp);
+	res->type = type;
+}
+EXPORT_SYMBOL(rdma_restrack_new);
+
 static void rdma_restrack_add(struct rdma_restrack_entry *res)
 {
 	struct ib_device *dev = res_to_dev(res);
@@ -213,8 +228,6 @@ static void rdma_restrack_add(struct rdma_restrack_entry *res)
 
 	rt = &dev->res[res->type];
 
-	kref_init(&res->kref);
-	init_completion(&res->comp);
 	if (res->type == RDMA_RESTRACK_QP) {
 		/* Special case to ensure that LQPN points to right QP */
 		struct ib_qp *qp = container_of(res, struct ib_qp, res);
@@ -305,6 +318,10 @@ static void restrack_release(struct kref *kref)
 	struct rdma_restrack_entry *res;
 
 	res = container_of(kref, struct rdma_restrack_entry, kref);
+	if (res->task) {
+		put_task_struct(res->task);
+		res->task = NULL;
+	}
 	complete(&res->comp);
 }
 
@@ -314,14 +331,23 @@ int rdma_restrack_put(struct rdma_restrack_entry *res)
 }
 EXPORT_SYMBOL(rdma_restrack_put);
 
+/**
+ * rdma_restrack_del() - delete object from the reource tracking database
+ * @res:  resource entry
+ */
 void rdma_restrack_del(struct rdma_restrack_entry *res)
 {
 	struct rdma_restrack_entry *old;
 	struct rdma_restrack_root *rt;
 	struct ib_device *dev;
 
-	if (!res->valid)
-		goto out;
+	if (!res->valid) {
+		if (res->task) {
+			put_task_struct(res->task);
+			res->task = NULL;
+		}
+		return;
+	}
 
 	dev = res_to_dev(res);
 	if (WARN_ON(!dev))
@@ -330,16 +356,12 @@ void rdma_restrack_del(struct rdma_restrack_entry *res)
 	rt = &dev->res[res->type];
 
 	old = xa_erase(&rt->xa, res->id);
+	if (res->type == RDMA_RESTRACK_MR || res->type == RDMA_RESTRACK_QP)
+		return;
 	WARN_ON(old != res);
 	res->valid = false;
 
 	rdma_restrack_put(res);
 	wait_for_completion(&res->comp);
-
-out:
-	if (res->task) {
-		put_task_struct(res->task);
-		res->task = NULL;
-	}
 }
 EXPORT_SYMBOL(rdma_restrack_del);

drivers/infiniband/core/restrack.h

@@ -25,6 +25,9 @@ struct rdma_restrack_root {
 
 int rdma_restrack_init(struct ib_device *dev);
 void rdma_restrack_clean(struct ib_device *dev);
+void rdma_restrack_del(struct rdma_restrack_entry *res);
+void rdma_restrack_new(struct rdma_restrack_entry *res,
+		       enum rdma_restrack_type type);
 void rdma_restrack_attach_task(struct rdma_restrack_entry *res,
 			       struct task_struct *task);
 #endif /* _RDMA_CORE_RESTRACK_H_ */

drivers/infiniband/core/uverbs_cmd.c

@@ -218,10 +218,11 @@ int ib_alloc_ucontext(struct uverbs_attr_bundle *attrs)
 	if (!ucontext)
 		return -ENOMEM;
 
-	ucontext->res.type = RDMA_RESTRACK_CTX;
 	ucontext->device = ib_dev;
 	ucontext->ufile = ufile;
 	xa_init_flags(&ucontext->mmap_xa, XA_FLAGS_ALLOC);
+
+	rdma_restrack_new(&ucontext->res, RDMA_RESTRACK_CTX);
 	attrs->context = ucontext;
 	return 0;
 }
@@ -313,6 +314,7 @@ static int ib_uverbs_get_context(struct uverbs_attr_bundle *attrs)
 err_uobj:
 	rdma_alloc_abort_uobject(uobj, attrs, false);
 err_ucontext:
+	rdma_restrack_put(&attrs->context->res);
 	kfree(attrs->context);
 	attrs->context = NULL;
 	return ret;
@@ -439,8 +441,8 @@ static int ib_uverbs_alloc_pd(struct uverbs_attr_bundle *attrs)
 	pd->device  = ib_dev;
 	pd->uobject = uobj;
 	atomic_set(&pd->usecnt, 0);
-	pd->res.type = RDMA_RESTRACK_PD;
 
+	rdma_restrack_new(&pd->res, RDMA_RESTRACK_PD);
 	ret = ib_dev->ops.alloc_pd(pd, &attrs->driver_udata);
 	if (ret)
 		goto err_alloc;
@@ -453,6 +455,7 @@ static int ib_uverbs_alloc_pd(struct uverbs_attr_bundle *attrs)
 	return uverbs_response(attrs, &resp, sizeof(resp));
 
 err_alloc:
+	rdma_restrack_put(&pd->res);
 	kfree(pd);
 err:
 	uobj_alloc_abort(uobj, attrs);
@@ -742,8 +745,9 @@ static int ib_uverbs_reg_mr(struct uverbs_attr_bundle *attrs)
 	mr->sig_attrs = NULL;
 	mr->uobject = uobj;
 	atomic_inc(&pd->usecnt);
-	mr->res.type = RDMA_RESTRACK_MR;
 	mr->iova = cmd.hca_va;
+
+	rdma_restrack_new(&mr->res, RDMA_RESTRACK_MR);
 	rdma_restrack_uadd(&mr->res);
 
 	uobj->object = mr;
@@ -1002,8 +1006,8 @@ static int create_cq(struct uverbs_attr_bundle *attrs,
 	cq->event_handler = ib_uverbs_cq_event_handler;
 	cq->cq_context    = ev_file ? &ev_file->ev_queue : NULL;
 	atomic_set(&cq->usecnt, 0);
-	cq->res.type = RDMA_RESTRACK_CQ;
 
+	rdma_restrack_new(&cq->res, RDMA_RESTRACK_CQ);
 	ret = ib_dev->ops.create_cq(cq, &attr, &attrs->driver_udata);
 	if (ret)
 		goto err_free;
@@ -1021,6 +1025,7 @@ static int create_cq(struct uverbs_attr_bundle *attrs,
 	return uverbs_response(attrs, &resp, sizeof(resp));
 
 err_free:
+	rdma_restrack_put(&cq->res);
 	kfree(cq);
 err_file:
 	if (ev_file)

drivers/infiniband/core/uverbs_std_types_cq.c

@@ -33,6 +33,7 @@
 #include <rdma/uverbs_std_types.h>
 #include "rdma_core.h"
 #include "uverbs.h"
+#include "restrack.h"
 
 static int uverbs_free_cq(struct ib_uobject *uobject,
 			  enum rdma_remove_reason why,
@@ -123,8 +124,8 @@ static int UVERBS_HANDLER(UVERBS_METHOD_CQ_CREATE)(
 	cq->event_handler = ib_uverbs_cq_event_handler;
 	cq->cq_context    = ev_file ? &ev_file->ev_queue : NULL;
 	atomic_set(&cq->usecnt, 0);
-	cq->res.type = RDMA_RESTRACK_CQ;
 
+	rdma_restrack_new(&cq->res, RDMA_RESTRACK_CQ);
 	ret = ib_dev->ops.create_cq(cq, &attr, &attrs->driver_udata);
 	if (ret)
 		goto err_free;
@@ -139,6 +140,7 @@ static int UVERBS_HANDLER(UVERBS_METHOD_CQ_CREATE)(
 	return ret;
 
 err_free:
+	rdma_restrack_put(&cq->res);
 	kfree(cq);
 err_event_file:
 	if (obj->uevent.event_file)

drivers/infiniband/core/verbs.c

@@ -272,11 +272,12 @@ struct ib_pd *__ib_alloc_pd(struct ib_device *device, unsigned int flags,
 	atomic_set(&pd->usecnt, 0);
 	pd->flags = flags;
 
-	pd->res.type = RDMA_RESTRACK_PD;
+	rdma_restrack_new(&pd->res, RDMA_RESTRACK_PD);
 	rdma_restrack_set_task(&pd->res, caller);
 
 	ret = device->ops.alloc_pd(pd, NULL);
 	if (ret) {
+		rdma_restrack_put(&pd->res);
 		kfree(pd);
 		return ERR_PTR(ret);
 	}
@@ -1996,11 +1997,13 @@ struct ib_cq *__ib_create_cq(struct ib_device *device,
 	cq->event_handler = event_handler;
 	cq->cq_context = cq_context;
 	atomic_set(&cq->usecnt, 0);
-	cq->res.type = RDMA_RESTRACK_CQ;
+
+	rdma_restrack_new(&cq->res, RDMA_RESTRACK_CQ);
 	rdma_restrack_set_task(&cq->res, caller);
 
 	ret = device->ops.create_cq(cq, cq_attr, NULL);
 	if (ret) {
+		rdma_restrack_put(&cq->res);
 		kfree(cq);
 		return ERR_PTR(ret);
 	}
@@ -2076,7 +2079,8 @@ struct ib_mr *ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	mr->pd = pd;
 	mr->dm = NULL;
 	atomic_inc(&pd->usecnt);
-	mr->res.type = RDMA_RESTRACK_MR;
+
+	rdma_restrack_new(&mr->res, RDMA_RESTRACK_MR);
 	rdma_restrack_kadd(&mr->res);
 
 	return mr;
@@ -2156,11 +2160,11 @@ struct ib_mr *ib_alloc_mr(struct ib_pd *pd, enum ib_mr_type mr_type,
 	mr->uobject = NULL;
 	atomic_inc(&pd->usecnt);
 	mr->need_inval = false;
-	mr->res.type = RDMA_RESTRACK_MR;
-	rdma_restrack_kadd(&mr->res);
 	mr->type = mr_type;
 	mr->sig_attrs = NULL;
 
+	rdma_restrack_new(&mr->res, RDMA_RESTRACK_MR);
+	rdma_restrack_kadd(&mr->res);
 out:
 	trace_mr_alloc(pd, mr_type, max_num_sg, mr);
 	return mr;
@@ -2216,11 +2220,11 @@ struct ib_mr *ib_alloc_mr_integrity(struct ib_pd *pd,
 	mr->uobject = NULL;
 	atomic_inc(&pd->usecnt);
 	mr->need_inval = false;
-	mr->res.type = RDMA_RESTRACK_MR;
-	rdma_restrack_kadd(&mr->res);
 	mr->type = IB_MR_TYPE_INTEGRITY;
 	mr->sig_attrs = sig_attrs;
 
+	rdma_restrack_new(&mr->res, RDMA_RESTRACK_MR);
+	rdma_restrack_kadd(&mr->res);
 out:
 	trace_mr_integ_alloc(pd, max_num_data_sg, max_num_meta_sg, mr);
 	return mr;

include/rdma/restrack.h

@@ -110,13 +110,6 @@ int rdma_restrack_count(struct ib_device *dev,
 void rdma_restrack_kadd(struct rdma_restrack_entry *res);
 void rdma_restrack_uadd(struct rdma_restrack_entry *res);
 
-/**
- * rdma_restrack_del() - delete object from the reource tracking database
- * @res:  resource entry
- * @type: actual type of object to operate
- */
-void rdma_restrack_del(struct rdma_restrack_entry *res);
-
 /**
  * rdma_is_kernel_res() - check the owner of resource
  * @res:  resource entry