Changeset f527f58 in mainline for uspace/lib/usbhost/src/endpoint.c

Timestamp:

2016-08-03T11:12:24Z (9 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

96ef672

Parents:

e657635

Message:

Reference-count endpoint_t structures

Track explicit references to USB endpoints. Call endpoint_destroy()
only after the last reference is destroyed. This prevents the scenario
in which removal was attempted on an endpoint while there was a transfer
in progress.

File:

• uspace/lib/usbhost/src/endpoint.c (modified) (7 diffs)

uspace/lib/usbhost/src/endpoint.c

@@ -26 +26 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
+
 /** @addtogroup libusbhost
  * @{
@@ -37 +38 @@
 #include <assert.h>
 #include <stdlib.h>
+#include <atomic.h>
 
 /** Allocate ad initialize endpoint_t structure.
@@ -55 +57 @@
         endpoint_t *instance = malloc(sizeof(endpoint_t));
         if (instance) {
+                atomic_set(&instance->refcnt, 0);
                 instance->address = address;
                 instance->endpoint = endpoint;
@@ -83 +86 @@
 {
         assert(instance);
-        //TODO: Do something about waiting fibrils.
         assert(!instance->active);
         assert(instance->hc_data.data == NULL);
         free(instance);
+}
+
+void endpoint_add_ref(endpoint_t *instance)
+{
+        atomic_inc(&instance->refcnt);
+}
+
+void endpoint_del_ref(endpoint_t *instance)
+{
+        if (atomic_predec(&instance->refcnt) == 0)
+                endpoint_destroy(instance);
 }
 
@@ -122 +135 @@
 {
         assert(instance);
+        /* Add reference for active endpoint. */
+        endpoint_add_ref(instance);
         fibril_mutex_lock(&instance->guard);
         while (instance->active)
@@ -139 +154 @@
         fibril_mutex_unlock(&instance->guard);
         fibril_condvar_signal(&instance->avail);
+        /* Drop reference for active endpoint. */
+        endpoint_del_ref(instance);
 }
 
@@ -171 +188 @@
         fibril_mutex_unlock(&instance->guard);
 }
+
 /**
  * @}