Changeset 7c7aae16 in mainline for generic/src/ipc/ipcrsc.c

Timestamp:

2006-03-19T19:42:00Z (19 years ago)

Author:

Ondrej Palkovsky <ondrap@…>

Branches:

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

Children:

ad64a2d

Parents:

9f22213

Message:

Reduced unnecessary IPC system calls.
Allow everything to be sync & async, everything is handled using messages.

File:

• generic/src/ipc/ipcrsc.c (modified) (4 diffs)

generic/src/ipc/ipcrsc.c

@@ -63 +63 @@
  * Destroying is less frequent, this approach is taken.
  *
+ * Phone call
+ *
+ * *** Connect_me_to ***
+ * The caller sends IPC_M_CONNECT_ME_TO to an answerbox. The server
+ * receives 'phoneid' of the connecting phone as an ARG3. If it answers
+ * with RETVAL=0, the phonecall is accepted, otherwise it is refused.
+ *
+ * *** Connect_to_me ***
+ * The caller sends IPC_M_CONNECT_TO_ME, with special 
+ * The server receives an automatically
+ * opened phoneid. If it accepts (RETVAL=0), it can use the phoneid
+ * immediately. 
+ * Possible race condition can arise, when the client receives messages
+ * from new connection before getting response for connect_to_me message.
+ * Userspace should implement handshake protocol that would control it.
+ *
  * Phone hangup
  * 
@@ -101 +117 @@
  *    appropriate error code (EHANGUP, EFORWARD).
  *
- * 4) Wait for all async answers to arrive.
+ * 4) Wait for all async answers to arrive and dispose of them.
  * 
  */
@@ -143 +159 @@
 }
 
-/** Disconnect phone a free the slot
+static void phone_deallocp(phone_t *phone)
+{
+        ASSERT(phone->busy == IPC_BUSY_CONNECTING);
+        ASSERT(! phone->callee);
+        
+        /* atomic operation */
+        phone->busy = IPC_BUSY_FREE;
+}
+
+/** Free slot from a disconnected phone
  *
  * All already sent messages will be correctly processed
@@ -149 +174 @@
 void phone_dealloc(int phoneid)
 {
-        spinlock_lock(&TASK->lock);
-
-        ASSERT(TASK->phones[phoneid].busy == IPC_BUSY_CONNECTING);
-        ASSERT(! TASK->phones[phoneid].callee);
-
-        TASK->phones[phoneid].busy = IPC_BUSY_FREE;
-        spinlock_unlock(&TASK->lock);
+        phone_deallocp(&TASK->phones[phoneid]);
 }