Changeset c721d26 in mainline

Timestamp:

2015-06-16T14:18:22Z (10 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

2654afb

Parents:

f7aa7a40

Message:

The async_futex must also be held during FIBRIL_FROM_DEAD.
Add the missing futex_down() to fibril_main() and async_manager().
Add an assert to fibril_switch().

Location:

uspace/lib/c

Files:

• generic/fibril.c (modified) (4 diffs)
• include/async.h (modified) (1 diff)

uspace/lib/c/generic/fibril.c

@@ -96 +96 @@
         fibril->retval = fibril->func(fibril->arg);
         
+        futex_down(&async_futex);
         fibril_switch(FIBRIL_FROM_DEAD);
         /* Not reached */
@@ -147 +148 @@
 /** Switch from the current fibril.
  *
- * If calling with FIBRIL_TO_MANAGER parameter, the async_futex should be
- * held.
+ * If stype is FIBRIL_TO_MANAGER or FIBRIL_FROM_DEAD, the async_futex must
+ * be held.
  *
  * @param stype Switch type. One of FIBRIL_PREEMPT, FIBRIL_TO_MANAGER,
@@ -163 +164 @@
         
         futex_lock(&fibril_futex);
-        
+
         if (stype == FIBRIL_PREEMPT && list_empty(&ready_list))
                 goto ret_0;
@@ -183 +184 @@
         /* If we are going to manager and none exists, create it */
         if ((stype == FIBRIL_TO_MANAGER) || (stype == FIBRIL_FROM_DEAD)) {
+                /* Make sure the async_futex is held. */
+                assert((atomic_signed_t) async_futex.val.count <= 0);
+
                 while (list_empty(&manager_list)) {
                         futex_unlock(&fibril_futex);

uspace/lib/c/include/async.h

@@ -108 +108 @@
 
 #define async_manager() \
-        fibril_switch(FIBRIL_TO_MANAGER)
+        do { \
+                futex_down(&async_futex); \
+                fibril_switch(FIBRIL_FROM_DEAD); \
+        } while (0)
 
 #define async_get_call(data) \