Changeset a6240a31 in mainline

Timestamp:

2012-01-23T16:27:01Z (12 years ago)

Author:

Martin Decky <martin@…>

Branches:

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

Children:

cd66f3c

Parents:

88057e3

Message:

improve locking by making the critical-path critical section smaller and the non-critical-path critical section larger

File:

• uspace/lib/c/generic/loc.c (modified) (7 diffs)

uspace/lib/c/generic/loc.c

@@ -47 +47 @@
 static FIBRIL_MUTEX_INITIALIZE(loc_callback_mutex);
 static bool loc_callback_created = false;
+static loc_cat_change_cb_t cat_change_cb = NULL;
 
 static async_sess_t *loc_supp_block_sess = NULL;
@@ -54 +55 @@
 static async_sess_t *loc_consumer_sess = NULL;
 
-static loc_cat_change_cb_t cat_change_cb = NULL;
-
 static void loc_cb_conn(ipc_callid_t iid, ipc_call_t *icall, void *arg)
 {
-        loc_cat_change_cb_t cb_fun;
-        
         while (true) {
                 ipc_call_t call;
@@ -69 +66 @@
                 }
                 
-                int retval;
-                
                 switch (IPC_GET_IMETHOD(call)) {
                 case LOC_EVENT_CAT_CHANGE:
                         fibril_mutex_lock(&loc_callback_mutex);
-                        cb_fun = cat_change_cb;
-                        if (cb_fun != NULL) {
+                        loc_cat_change_cb_t cb_fun = cat_change_cb;
+                        fibril_mutex_unlock(&loc_callback_mutex);
+                        
+                        async_answer_0(callid, EOK);
+                        
+                        if (cb_fun != NULL)
                                 (*cb_fun)();
-                        }
-                        fibril_mutex_unlock(&loc_callback_mutex);
-                        retval = 0;
+                        
                         break;
                 default:
-                        retval = ENOTSUP;
+                        async_answer_0(callid, ENOTSUP);
                 }
-                
-                async_answer_0(callid, retval);
         }
 }
@@ -101 +96 @@
 }
 
+/** Create callback
+ *
+ * Must be called with loc_callback_mutex locked.
+ *
+ * @return EOK on success.
+ *
+ */
 static int loc_callback_create(void)
 {
-        async_exch_t *exch;
-        sysarg_t retval;
-        int rc = EOK;
-
-        fibril_mutex_lock(&loc_callback_mutex);
-        
         if (!loc_callback_created) {
-                exch = loc_exchange_begin_blocking(LOC_PORT_CONSUMER);
+                async_exch_t *exch =
+                    loc_exchange_begin_blocking(LOC_PORT_CONSUMER);
                 
                 ipc_call_t answer;
@@ -117 +114 @@
                 loc_exchange_end(exch);
                 
-                async_wait_for(req, &retval);
                 if (rc != EOK)
-                        goto done;
+                        return rc;
                 
                 if (retval != EOK) {
@@ -129 +125 @@
         }
         
-        rc = EOK;
-done:
-        fibril_mutex_unlock(&loc_callback_mutex);
-        return rc;
+        return EOK;
 }
 
@@ -861 +854 @@
 int loc_register_cat_change_cb(loc_cat_change_cb_t cb_fun)
 {
-        if (loc_callback_create() != EOK)
+        fibril_mutex_lock(&loc_callback_mutex);
+        if (loc_callback_create() != EOK) {
+                fibril_mutex_unlock(&loc_callback_mutex);
                 return EIO;
-
+        }
+        
         cat_change_cb = cb_fun;
+        fibril_mutex_unlock(&loc_callback_mutex);
+        
         return EOK;
 }