IB/rdma_cm: Add wrapper for cma reference count

Currently, cma users can't increase or decrease the cma reference
count. This is necassary when setting cma attributes (like the
default GID type) in order to avoid use-after-free errors.
Adding cma_ref_dev and cma_deref_dev APIs.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index fce11dfd0c6972b4a087eb30320035fcae0d54ab..322f1c6a6bf36bee3424684f45387978731346d0 100644 (file)
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -60,6 +60,8 @@
 #include <rdma/ib_sa.h>
 #include <rdma/iw_cm.h>
 
+#include "core_priv.h"
+
 MODULE_AUTHOR("Sean Hefty");
 MODULE_DESCRIPTION("Generic RDMA CM Agent");
 MODULE_LICENSE("Dual BSD/GPL");
@@ -185,6 +187,11 @@ enum {
        CMA_OPTION_AFONLY,
 };
 
+void cma_ref_dev(struct cma_device *cma_dev)
+{
+       atomic_inc(&cma_dev->refcount);
+}
+
 /*
  * Device removal can occur at anytime, so we need extra handling to
  * serialize notifying the user of device removal with other callbacks.
@@ -339,7 +346,7 @@ static inline void cma_set_ip_ver(struct cma_hdr *hdr, u8 ip_ver)
 static void cma_attach_to_dev(struct rdma_id_private *id_priv,
                              struct cma_device *cma_dev)
 {
-       atomic_inc(&cma_dev->refcount);
+       cma_ref_dev(cma_dev);
        id_priv->cma_dev = cma_dev;
        id_priv->id.device = cma_dev->device;
        id_priv->id.route.addr.dev_addr.transport =
@@ -347,7 +354,7 @@ static void cma_attach_to_dev(struct rdma_id_private *id_priv,
        list_add_tail(&id_priv->list, &cma_dev->id_list);
 }
 
-static inline void cma_deref_dev(struct cma_device *cma_dev)
+void cma_deref_dev(struct cma_device *cma_dev)
 {
        if (atomic_dec_and_test(&cma_dev->refcount))
                complete(&cma_dev->comp);

diff --git a/drivers/infiniband/core/core_priv.h b/drivers/infiniband/core/core_priv.h
index 3b250a2f86b405c2f6195b1ededbcee06671a0f4..1945b4eccbbb61de301e8c85188da5914e1929c7 100644 (file)
--- a/drivers/infiniband/core/core_priv.h
+++ b/drivers/infiniband/core/core_priv.h
@@ -38,6 +38,10 @@
 
 #include <rdma/ib_verbs.h>
 
+struct cma_device;
+void cma_ref_dev(struct cma_device *cma_dev);
+void cma_deref_dev(struct cma_device *cma_dev);
+
 int  ib_device_register_sysfs(struct ib_device *device,
                              int (*port_callback)(struct ib_device *,
                                                   u8, struct kobject *));