X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=kitten%2Finclude%2Flwk%2Fwaitq.h;fp=kitten%2Finclude%2Flwk%2Fwaitq.h;h=f77c7e8e0621cb2cebe236f158ee847c7aaf377c;hb=66a1a4c7a9edcd7d8bc207aca093d694a6e6b5b2;hp=0000000000000000000000000000000000000000;hpb=f7cf9c19ecb0a589dd45ae0d2c91814bd3c2acc2;p=palacios.git

diff --git a/kitten/include/lwk/waitq.h b/kitten/include/lwk/waitq.h
new file mode 100644
index 0000000..f77c7e8
--- /dev/null
+++ b/kitten/include/lwk/waitq.h
@@ -0,0 +1,57 @@
+#ifndef _LWK_WAITQ_H
+#define _LWK_WAITQ_H
+
+#include <lwk/spinlock.h>
+#include <lwk/list.h>
+#include <lwk/task.h>
+
+typedef struct waitq {
+	spinlock_t           lock;
+	struct list_head     waitq;
+} waitq_t;
+
+typedef struct waitq_entry {
+	struct task_struct * task;
+	struct list_head     link;
+} waitq_entry_t;
+
+#define DECLARE_WAITQ(name)                             \
+	waitq_t name = {                                \
+	    .lock  = SPIN_LOCK_UNLOCKED,                \
+	    .waitq = { &(name).waitq, &(name).waitq }   \
+	}
+
+#define DECLARE_WAITQ_ENTRY(name, tsk)                  \
+	waitq_entry_t name = {                          \
+	    .task  = tsk,                               \
+	    .link  = { &(name).link, &(name).link }     \
+	}
+
+extern void waitq_init(waitq_t *waitq);
+extern void waitq_init_entry(waitq_entry_t *entry, struct task_struct *task);
+extern bool waitq_active(waitq_t *waitq);
+extern void waitq_add_entry(waitq_t *waitq, waitq_entry_t *entry);
+extern void waitq_prepare_to_wait(waitq_t *waitq, waitq_entry_t *entry,
+                                  taskstate_t state);
+extern void waitq_finish_wait(waitq_t *waitq, waitq_entry_t *entry);
+extern void waitq_wakeup(waitq_t *waitq);
+
+/**
+ * This puts the task to sleep until condition becomes true.
+ * This must be a macro because condition is tested repeatedly, not just
+ * when wait_event() is first called.
+ */
+#define wait_event(waitq, condition)                               \
+do {                                                               \
+	DECLARE_WAITQ_ENTRY(__entry, current);                     \
+	for (;;) {                                                 \
+		waitq_prepare_to_wait(&waitq, &__entry,            \
+		                      TASKSTATE_UNINTERRUPTIBLE);  \
+		if (condition)                                     \
+			break;                                     \
+		schedule();                                        \
+	}                                                          \
+	waitq_finish_wait(&waitq, &__entry);                       \
+} while (0)
+
+#endif