[patch 01/13] syslets: add async.h include file, kernel-side API definitions

Ingo Molnar
2007-02-21T21:19:41Z

From: Ingo Molnar <mingo@elte.hu>

add include/linux/async.h which contains the kernel-side API
declarations.

it also provides NOP stubs for the !CONFIG_ASYNC_SUPPORT case.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
include/linux/async.h | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 92 insertions(+)

Index: linux/include/linux/async.h
===================================================================
--- /dev/null
+++ linux/include/linux/async.h
@@ -0,0 +1,92 @@
+#ifndef _LINUX_ASYNC_H
+#define _LINUX_ASYNC_H
+
+#include <linux/completion.h>
+#include <linux/compiler.h>
+
+/*
+ * The syslet subsystem - asynchronous syscall execution support.
+ *
+ * Generic kernel API definitions:
+ */
+
+struct syslet_uatom;
+struct async_thread;
+struct async_head;
+
+/*
+ * The syslet subsystem - asynchronous syscall execution support.
+ *
+ * Syslet-subsystem internal definitions:
+ */
+
+/*
+ * The kernel-side copy of a syslet atom - with arguments expanded:
+ */
+struct syslet_atom {
+ unsigned long flags;
+ unsigned long nr;
+ long __user *ret_ptr;
+ struct syslet_uatom __user *next;
+ unsigned long args[6];
+};
+
+/*
+ * The 'async head' is the thread which has user-space context (ptregs)
+ * 'below it' - this is the one that can return to user-space:
+ */
+struct async_head {
+ spinlock_t lock;
+ struct task_struct *user_task;
+
+ struct list_head ready_async_threads;
+ struct list_head busy_async_threads;
+
+ struct mutex completion_lock;
+ long events_left;
+ wait_queue_head_t wait;
+
+ struct async_head_user __user *ahu;
+
+ unsigned long __user *new_stackp;
+ unsigned long new_eip;
+ unsigned long restore_stack;
+ unsigned long restore_eip;
+ struct completion start_done;
+ struct completion exit_done;
+};
+
+/*
+ * The 'async thread' is either a newly created async thread or it is
+ * an 'ex-head' - it cannot return to user-space and only has kernel
+ * context.
+ */
+struct async_thread {
+ struct task_struct *task;
+ struct syslet_uatom __user *work;
+ unsigned long user_stack;
+ unsigned long user_eip;
+ struct async_head *ah;
+
+ struct list_head entry;
+
+ unsigned int exit;
+};
+
+#ifdef CONFIG_ASYNC_SUPPORT
+extern void async_init(struct task_struct *t);
+extern void async_exit(struct task_struct *t);
+extern void __async_schedule(struct task_struct *t);
+#else /* !CONFIG_ASYNC_SUPPORT */
+static inline void async_init(struct task_struct *t)
+{
+}
+static inline void async_exit(struct task_struct *t)
+{
+}
+static inline void __async_schedule(struct task_struct *t)
+{
+}
+#endif /* !CONFIG_ASYNC_SUPPORT */
+
+#endif