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-rw-r--r--Makefile.objs2
-rw-r--r--qemu-coroutine-int.h1
-rw-r--r--qemu-coroutine-lock.c124
-rw-r--r--qemu-coroutine.h64
-rw-r--r--trace-events8
5 files changed, 198 insertions, 1 deletions
diff --git a/Makefile.objs b/Makefile.objs
index 9549e2a16..89ca3611b 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -12,7 +12,7 @@ oslib-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o
#######################################################################
# coroutines
-coroutine-obj-y = qemu-coroutine.o
+coroutine-obj-y = qemu-coroutine.o qemu-coroutine-lock.o
ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)
coroutine-obj-$(CONFIG_POSIX) += coroutine-ucontext.o
else
diff --git a/qemu-coroutine-int.h b/qemu-coroutine-int.h
index 64915c2fa..d495615cf 100644
--- a/qemu-coroutine-int.h
+++ b/qemu-coroutine-int.h
@@ -38,6 +38,7 @@ struct Coroutine {
void *entry_arg;
Coroutine *caller;
QLIST_ENTRY(Coroutine) pool_next;
+ QTAILQ_ENTRY(Coroutine) co_queue_next;
};
Coroutine *qemu_coroutine_new(void);
diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c
new file mode 100644
index 000000000..abaa1f796
--- /dev/null
+++ b/qemu-coroutine-lock.c
@@ -0,0 +1,124 @@
+/*
+ * coroutine queues and locks
+ *
+ * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu-common.h"
+#include "qemu-coroutine.h"
+#include "qemu-coroutine-int.h"
+#include "qemu-queue.h"
+#include "trace.h"
+
+static QTAILQ_HEAD(, Coroutine) unlock_bh_queue =
+ QTAILQ_HEAD_INITIALIZER(unlock_bh_queue);
+
+struct unlock_bh {
+ QEMUBH *bh;
+};
+
+static void qemu_co_queue_next_bh(void *opaque)
+{
+ struct unlock_bh *unlock_bh = opaque;
+ Coroutine *next;
+
+ trace_qemu_co_queue_next_bh();
+ while ((next = QTAILQ_FIRST(&unlock_bh_queue))) {
+ QTAILQ_REMOVE(&unlock_bh_queue, next, co_queue_next);
+ qemu_coroutine_enter(next, NULL);
+ }
+
+ qemu_bh_delete(unlock_bh->bh);
+ qemu_free(unlock_bh);
+}
+
+void qemu_co_queue_init(CoQueue *queue)
+{
+ QTAILQ_INIT(&queue->entries);
+}
+
+void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
+{
+ Coroutine *self = qemu_coroutine_self();
+ QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
+ qemu_coroutine_yield();
+ assert(qemu_in_coroutine());
+}
+
+bool qemu_co_queue_next(CoQueue *queue)
+{
+ struct unlock_bh *unlock_bh;
+ Coroutine *next;
+
+ next = QTAILQ_FIRST(&queue->entries);
+ if (next) {
+ QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
+ QTAILQ_INSERT_TAIL(&unlock_bh_queue, next, co_queue_next);
+ trace_qemu_co_queue_next(next);
+
+ unlock_bh = qemu_malloc(sizeof(*unlock_bh));
+ unlock_bh->bh = qemu_bh_new(qemu_co_queue_next_bh, unlock_bh);
+ qemu_bh_schedule(unlock_bh->bh);
+ }
+
+ return (next != NULL);
+}
+
+bool qemu_co_queue_empty(CoQueue *queue)
+{
+ return (QTAILQ_FIRST(&queue->entries) == NULL);
+}
+
+void qemu_co_mutex_init(CoMutex *mutex)
+{
+ memset(mutex, 0, sizeof(*mutex));
+ qemu_co_queue_init(&mutex->queue);
+}
+
+void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
+{
+ Coroutine *self = qemu_coroutine_self();
+
+ trace_qemu_co_mutex_lock_entry(mutex, self);
+
+ while (mutex->locked) {
+ qemu_co_queue_wait(&mutex->queue);
+ }
+
+ mutex->locked = true;
+
+ trace_qemu_co_mutex_lock_return(mutex, self);
+}
+
+void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
+{
+ Coroutine *self = qemu_coroutine_self();
+
+ trace_qemu_co_mutex_unlock_entry(mutex, self);
+
+ assert(mutex->locked == true);
+ assert(qemu_in_coroutine());
+
+ mutex->locked = false;
+ qemu_co_queue_next(&mutex->queue);
+
+ trace_qemu_co_mutex_unlock_return(mutex, self);
+}
diff --git a/qemu-coroutine.h b/qemu-coroutine.h
index 08255c7c4..2f2fd9555 100644
--- a/qemu-coroutine.h
+++ b/qemu-coroutine.h
@@ -5,6 +5,7 @@
*
* Authors:
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
+ * Kevin Wolf <kwolf@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
@@ -15,6 +16,7 @@
#define QEMU_COROUTINE_H
#include <stdbool.h>
+#include "qemu-queue.h"
/**
* Coroutines are a mechanism for stack switching and can be used for
@@ -92,4 +94,66 @@ Coroutine *coroutine_fn qemu_coroutine_self(void);
*/
bool qemu_in_coroutine(void);
+
+
+/**
+ * CoQueues are a mechanism to queue coroutines in order to continue executing
+ * them later. They provide the fundamental primitives on which coroutine locks
+ * are built.
+ */
+typedef struct CoQueue {
+ QTAILQ_HEAD(, Coroutine) entries;
+} CoQueue;
+
+/**
+ * Initialise a CoQueue. This must be called before any other operation is used
+ * on the CoQueue.
+ */
+void qemu_co_queue_init(CoQueue *queue);
+
+/**
+ * Adds the current coroutine to the CoQueue and transfers control to the
+ * caller of the coroutine.
+ */
+void coroutine_fn qemu_co_queue_wait(CoQueue *queue);
+
+/**
+ * Restarts the next coroutine in the CoQueue and removes it from the queue.
+ *
+ * Returns true if a coroutine was restarted, false if the queue is empty.
+ */
+bool qemu_co_queue_next(CoQueue *queue);
+
+/**
+ * Checks if the CoQueue is empty.
+ */
+bool qemu_co_queue_empty(CoQueue *queue);
+
+
+/**
+ * Provides a mutex that can be used to synchronise coroutines
+ */
+typedef struct CoMutex {
+ bool locked;
+ CoQueue queue;
+} CoMutex;
+
+/**
+ * Initialises a CoMutex. This must be called before any other operation is used
+ * on the CoMutex.
+ */
+void qemu_co_mutex_init(CoMutex *mutex);
+
+/**
+ * Locks the mutex. If the lock cannot be taken immediately, control is
+ * transferred to the caller of the current coroutine.
+ */
+void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex);
+
+/**
+ * Unlocks the mutex and schedules the next coroutine that was waiting for this
+ * lock to be run.
+ */
+void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
+
#endif /* QEMU_COROUTINE_H */
diff --git a/trace-events b/trace-events
index bc9be3010..19d31e354 100644
--- a/trace-events
+++ b/trace-events
@@ -433,3 +433,11 @@ disable xen_platform_log(char *s) "xen platform: %s"
disable qemu_coroutine_enter(void *from, void *to, void *opaque) "from %p to %p opaque %p"
disable qemu_coroutine_yield(void *from, void *to) "from %p to %p"
disable qemu_coroutine_terminate(void *co) "self %p"
+
+# qemu-coroutine-lock.c
+disable qemu_co_queue_next_bh(void) ""
+disable qemu_co_queue_next(void *next) "next %p"
+disable qemu_co_mutex_lock_entry(void *mutex, void *self) "mutex %p self %p"
+disable qemu_co_mutex_lock_return(void *mutex, void *self) "mutex %p self %p"
+disable qemu_co_mutex_unlock_entry(void *mutex, void *self) "mutex %p self %p"
+disable qemu_co_mutex_unlock_return(void *mutex, void *self) "mutex %p self %p"