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

Timestamp:

2016-08-03T11:12:24Z (8 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/usb_bus.c (modified) (6 diffs)

uspace/lib/usbhost/src/usb_bus.c

@@ -242 +242 @@
                 return EEXIST;
         }
+        /* Add endpoint list's reference to ep. */
+        endpoint_add_ref(ep);
         list_append(&ep->link, get_list(instance, ep->address));
 
@@ -274 +276 @@
             ep->endpoint, usb_str_transfer_type_short(ep->transfer_type),
             usb_str_direction(ep->direction));
+        /* Drop endpoint list's reference to ep. */
+        endpoint_del_ref(ep);
         fibril_mutex_unlock(&instance->guard);
         return EOK;
@@ -289 +293 @@
         fibril_mutex_lock(&instance->guard);
         endpoint_t *ep = find_locked(instance, address, endpoint, direction);
+        if (ep) {
+                /* We are exporting ep to the outside world, add reference. */
+                endpoint_add_ref(ep);
+        }
         fibril_mutex_unlock(&instance->guard);
         return ep;
@@ -350 +358 @@
         }
 
+        /* Add our reference to ep. */
+        endpoint_add_ref(ep);
+
         if (callback) {
                 const int ret = callback(ep, arg);
                 if (ret != EOK) {
                         fibril_mutex_unlock(&instance->guard);
-                        endpoint_destroy(ep);
+                        endpoint_del_ref(ep);
                         return ret;
                 }
         }
+        
+        /* Add endpoint list's reference to ep. */
+        endpoint_add_ref(ep);
         list_append(&ep->link, get_list(instance, ep->address));
 
         instance->free_bw -= ep->bandwidth;
         fibril_mutex_unlock(&instance->guard);
+
+        /* Drop our reference to ep. */
+        endpoint_del_ref(ep);
+
         return EOK;
 }
@@ -392 +410 @@
                 callback(ep, arg);
         }
-        endpoint_destroy(ep);
+        /* Drop endpoint list's reference to ep. */
+        endpoint_del_ref(ep);
         return EOK;
 }
@@ -445 +464 @@
                         if (callback)
                                 callback(ep, arg);
-                        endpoint_destroy(ep);
+                        /* Drop endpoint list's reference to ep. */
+                        endpoint_del_ref(ep);
                 }
         }