Changeset 203f4c3 in mainline for generic/src/synch/waitq.c

Timestamp:

2006-04-09T14:14:49Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

016acbe

Parents:

fe04594

Message:

Sleeping in a wait queue can be now interrupted with
waitq_interrupt_sleep().

File:

• generic/src/synch/waitq.c (modified) (7 diffs)

generic/src/synch/waitq.c

@@ -40 +40 @@
 #include <adt/list.h>
 
+static void waitq_timeouted_sleep(void *data);
+
 /** Initialize wait queue
  *
@@ -65 +67 @@
  * @param data Pointer to the thread that called waitq_sleep_timeout().
  */
-void waitq_interrupted_sleep(void *data)
+void waitq_timeouted_sleep(void *data)
 {
         thread_t *t = (thread_t *) data;
@@ -101 +103 @@
 }
 
-/** Sleep until either wakeup or timeout occurs
+/** Interrupt sleeping thread.
+ *
+ * This routine attempts to interrupt a thread from its sleep in a waitqueue.
+ * If the thread is not found sleeping, no action is taken.
+ *
+ * @param t Thread to be interrupted.
+ */
+void waitq_interrupt_sleep(thread_t *t)
+{
+        waitq_t *wq;
+        bool do_wakeup = false;
+        ipl_t ipl;
+
+        ipl = interrupts_disable();
+        spinlock_lock(&threads_lock);
+        if (!list_member(&t->threads_link, &threads_head))
+                goto out;
+
+grab_locks:
+        spinlock_lock(&t->lock);
+        if ((wq = t->sleep_queue)) {            /* assignment */
+                if (!spinlock_trylock(&wq->lock)) {
+                        spinlock_unlock(&t->lock);
+                        goto grab_locks;        /* avoid deadlock */
+                }
+
+                list_remove(&t->wq_link);
+                t->saved_context = t->sleep_interruption_context;
+                do_wakeup = true;
+                
+                spinlock_unlock(&wq->lock);
+                t->sleep_queue = NULL;
+        }
+        spinlock_unlock(&t->lock);
+
+        if (do_wakeup)
+                thread_ready(t);
+
+out:
+        spinlock_unlock(&threads_lock);
+        interrupts_restore(ipl);
+}
+
+
+/** Sleep until either wakeup, timeout or interruption occurs
  *
  * This is a sleep implementation which allows itself to be
@@ -131 +177 @@
  *
  * ESYNCH_TIMEOUT means that the sleep timed out.
+ *
+ * ESYNCH_INTERRUPTED means that somebody interrupted the sleeping thread.
  *
  * ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was
@@ -179 +227 @@
                 }
         }
-
         
         /*
@@ -185 +232 @@
          */
         spinlock_lock(&THREAD->lock);
+
+        /*
+         * Set context that will be restored if the sleep
+         * of this thread is ever interrupted.
+         */
+        if (!context_save(&THREAD->sleep_interruption_context)) {
+                /* Short emulation of scheduler() return code. */
+                spinlock_unlock(&THREAD->lock);
+                interrupts_restore(ipl);
+                return ESYNCH_INTERRUPTED;
+        }
+
         if (usec) {
                 /* We use the timeout variant. */
                 if (!context_save(&THREAD->sleep_timeout_context)) {
-                        /*
-                         * Short emulation of scheduler() return code.
-                         */
+                        /* Short emulation of scheduler() return code. */
                         spinlock_unlock(&THREAD->lock);
                         interrupts_restore(ipl);
@@ -196 +253 @@
                 }
                 THREAD->timeout_pending = true;
-                timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, THREAD);
+                timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_timeouted_sleep, THREAD);
         }