On Fri, Feb 21, 2020 at 11:47:00AM +0100, Jack Wang wrote:

From: Jack Wang <jinpu.wang@cloud.ionos.com>

This is a set of library functions existing as a rtrs-core module,
used by client and server modules.

Mainly these functions wrap IB and RDMA calls and provide a bit higher
abstraction for implementing of RTRS protocol on client or server
sides.

Signed-off-by: Danil Kipnis <redacted>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
---
 drivers/infiniband/ulp/rtrs/rtrs.c | 594 +++++++++++++++++++++++++++++
 1 file changed, 594 insertions(+)
 create mode 100644 drivers/infiniband/ulp/rtrs/rtrs.c

<...>

+
+static void dev_free(struct kref *ref)
+{
+	struct rtrs_rdma_dev_pd *pool;
+	struct rtrs_ib_dev *dev;
+
+	dev = container_of(ref, typeof(*dev), ref);
+	pool = dev->pool;
+
+	mutex_lock(&pool->mutex);
+	list_del(&dev->entry);
+	mutex_unlock(&pool->mutex);
+
+	if (pool->ops && pool->ops->deinit)
+		pool->ops->deinit(dev);
+
+	ib_dealloc_pd(dev->ib_pd);
+
+	if (pool->ops && pool->ops->free)
+		pool->ops->free(dev);
+	else
+		kfree(dev);
+}
+
+int rtrs_ib_dev_put(struct rtrs_ib_dev *dev)
+{
+	return kref_put(&dev->ref, dev_free);
+}
+EXPORT_SYMBOL(rtrs_ib_dev_put);
+
+static int rtrs_ib_dev_get(struct rtrs_ib_dev *dev)
+{
+	return kref_get_unless_zero(&dev->ref);
+}
+
+struct rtrs_ib_dev *
+rtrs_ib_dev_find_or_add(struct ib_device *ib_dev,
+			 struct rtrs_rdma_dev_pd *pool)
+{
+	struct rtrs_ib_dev *dev;
+
+	mutex_lock(&pool->mutex);

The scope of this mutex is unclear, you protected everything here with
this mutex, but in dev_free() you guarded list_del() only.

+	list_for_each_entry(dev, &pool->list, entry) {
+		if (dev->ib_dev->node_guid == ib_dev->node_guid &&
+		    rtrs_ib_dev_get(dev))
+			goto out_unlock;
+	}
+	if (pool->ops && pool->ops->alloc)
+		dev = pool->ops->alloc();
+	else
+		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (IS_ERR_OR_NULL(dev))
+		goto out_err;
+
+	kref_init(&dev->ref);
+	dev->pool = pool;
+	dev->ib_dev = ib_dev;
+	dev->ib_pd = ib_alloc_pd(ib_dev, pool->pd_flags);
+	if (IS_ERR(dev->ib_pd))
+		goto out_free_dev;
+
+	if (pool->ops && pool->ops->init && pool->ops->init(dev))
+		goto out_free_pd;
+
+	list_add(&dev->entry, &pool->list);
+out_unlock:
+	mutex_unlock(&pool->mutex);
+	return dev;
+
+out_free_pd:
+	ib_dealloc_pd(dev->ib_pd);
+out_free_dev:
+	if (pool->ops && pool->ops->free)
+		pool->ops->free(dev);
+	else
+		kfree(dev);
+out_err:
+	mutex_unlock(&pool->mutex);
+	return NULL;
+}
+EXPORT_SYMBOL(rtrs_ib_dev_find_or_add);
--
2.17.1