@@ -3061,8 +3061,10 @@ S: Maintained
F: docs/devel/lockcnt.rst
F: docs/devel/rcu.rst
F: include/qemu/rcu*.h
+F: include/qemu/lockcnt.h
F: tests/unit/rcutorture.c
F: tests/unit/test-rcu-*.c
+F: util/lockcnt.c
F: util/rcu.c
Human Monitor (HMP)
@@ -175,7 +175,7 @@ three instructions in the critical path, two assignments and a ``smp_wmb()``.
``QemuLockCnt`` API
-------------------
-The ``QemuLockCnt`` API is described in ``include/qemu/thread.h``.
+The ``QemuLockCnt`` API is described in ``include/qemu/lockcnt.h``.
``QemuLockCnt`` usage
@@ -20,6 +20,7 @@
#include "qemu/coroutine-core.h"
#include "qemu/queue.h"
#include "qemu/event_notifier.h"
+#include "qemu/lockcnt.h"
#include "qemu/thread.h"
#include "qemu/timer.h"
#include "block/graph-lock.h"
@@ -33,6 +33,7 @@
#include "qemu/bitmap.h"
#include "qemu/rcu_queue.h"
#include "qemu/queue.h"
+#include "qemu/lockcnt.h"
#include "qemu/thread.h"
#include "qom/object.h"
new file mode 100644
@@ -0,0 +1,130 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * QemuLockCnt implementation
+ *
+ * Copyright Red Hat, Inc. 2017
+ *
+ * Author:
+ * Paolo Bonzini <pbonzini@redhat.com>
+ *
+ */
+
+#ifndef QEMU_LOCKCNT_H
+#define QEMU_LOCKCNT_H
+
+#include "qemu/thread.h"
+
+typedef struct QemuLockCnt QemuLockCnt;
+
+struct QemuLockCnt {
+#ifndef CONFIG_LINUX
+ QemuMutex mutex;
+#endif
+ unsigned count;
+};
+
+/**
+ * qemu_lockcnt_init: initialize a QemuLockcnt
+ * @lockcnt: the lockcnt to initialize
+ *
+ * Initialize lockcnt's counter to zero and prepare its mutex
+ * for usage.
+ */
+void qemu_lockcnt_init(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_destroy: destroy a QemuLockcnt
+ * @lockcnt: the lockcnt to destruct
+ *
+ * Destroy lockcnt's mutex.
+ */
+void qemu_lockcnt_destroy(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_inc: increment a QemuLockCnt's counter
+ * @lockcnt: the lockcnt to operate on
+ *
+ * If the lockcnt's count is zero, wait for critical sections
+ * to finish and increment lockcnt's count to 1. If the count
+ * is not zero, just increment it.
+ *
+ * Because this function can wait on the mutex, it must not be
+ * called while the lockcnt's mutex is held by the current thread.
+ * For the same reason, qemu_lockcnt_inc can also contribute to
+ * AB-BA deadlocks. This is a sample deadlock scenario:
+ *
+ * thread 1 thread 2
+ * -------------------------------------------------------
+ * qemu_lockcnt_lock(&lc1);
+ * qemu_lockcnt_lock(&lc2);
+ * qemu_lockcnt_inc(&lc2);
+ * qemu_lockcnt_inc(&lc1);
+ */
+void qemu_lockcnt_inc(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_dec: decrement a QemuLockCnt's counter
+ * @lockcnt: the lockcnt to operate on
+ */
+void qemu_lockcnt_dec(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_dec_and_lock: decrement a QemuLockCnt's counter and
+ * possibly lock it.
+ * @lockcnt: the lockcnt to operate on
+ *
+ * Decrement lockcnt's count. If the new count is zero, lock
+ * the mutex and return true. Otherwise, return false.
+ */
+bool qemu_lockcnt_dec_and_lock(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_dec_if_lock: possibly decrement a QemuLockCnt's counter and
+ * lock it.
+ * @lockcnt: the lockcnt to operate on
+ *
+ * If the count is 1, decrement the count to zero, lock
+ * the mutex and return true. Otherwise, return false.
+ */
+bool qemu_lockcnt_dec_if_lock(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_lock: lock a QemuLockCnt's mutex.
+ * @lockcnt: the lockcnt to operate on
+ *
+ * Remember that concurrent visits are not blocked unless the count is
+ * also zero. You can use qemu_lockcnt_count to check for this inside a
+ * critical section.
+ */
+void qemu_lockcnt_lock(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_unlock: release a QemuLockCnt's mutex.
+ * @lockcnt: the lockcnt to operate on.
+ */
+void qemu_lockcnt_unlock(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_inc_and_unlock: combined unlock/increment on a QemuLockCnt.
+ * @lockcnt: the lockcnt to operate on.
+ *
+ * This is the same as
+ *
+ * qemu_lockcnt_unlock(lockcnt);
+ * qemu_lockcnt_inc(lockcnt);
+ *
+ * but more efficient.
+ */
+void qemu_lockcnt_inc_and_unlock(QemuLockCnt *lockcnt);
+
+/**
+ * qemu_lockcnt_count: query a LockCnt's count.
+ * @lockcnt: the lockcnt to query.
+ *
+ * Note that the count can change at any time. Still, while the
+ * lockcnt is locked, one can usefully check whether the count
+ * is non-zero.
+ */
+unsigned qemu_lockcnt_count(QemuLockCnt *lockcnt);
+
+#endif
@@ -293,115 +293,4 @@ static inline void qemu_spin_unlock(QemuSpin *spin)
#endif
}
-struct QemuLockCnt {
-#ifndef CONFIG_LINUX
- QemuMutex mutex;
-#endif
- unsigned count;
-};
-
-/**
- * qemu_lockcnt_init: initialize a QemuLockcnt
- * @lockcnt: the lockcnt to initialize
- *
- * Initialize lockcnt's counter to zero and prepare its mutex
- * for usage.
- */
-void qemu_lockcnt_init(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_destroy: destroy a QemuLockcnt
- * @lockcnt: the lockcnt to destruct
- *
- * Destroy lockcnt's mutex.
- */
-void qemu_lockcnt_destroy(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_inc: increment a QemuLockCnt's counter
- * @lockcnt: the lockcnt to operate on
- *
- * If the lockcnt's count is zero, wait for critical sections
- * to finish and increment lockcnt's count to 1. If the count
- * is not zero, just increment it.
- *
- * Because this function can wait on the mutex, it must not be
- * called while the lockcnt's mutex is held by the current thread.
- * For the same reason, qemu_lockcnt_inc can also contribute to
- * AB-BA deadlocks. This is a sample deadlock scenario:
- *
- * thread 1 thread 2
- * -------------------------------------------------------
- * qemu_lockcnt_lock(&lc1);
- * qemu_lockcnt_lock(&lc2);
- * qemu_lockcnt_inc(&lc2);
- * qemu_lockcnt_inc(&lc1);
- */
-void qemu_lockcnt_inc(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_dec: decrement a QemuLockCnt's counter
- * @lockcnt: the lockcnt to operate on
- */
-void qemu_lockcnt_dec(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_dec_and_lock: decrement a QemuLockCnt's counter and
- * possibly lock it.
- * @lockcnt: the lockcnt to operate on
- *
- * Decrement lockcnt's count. If the new count is zero, lock
- * the mutex and return true. Otherwise, return false.
- */
-bool qemu_lockcnt_dec_and_lock(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_dec_if_lock: possibly decrement a QemuLockCnt's counter and
- * lock it.
- * @lockcnt: the lockcnt to operate on
- *
- * If the count is 1, decrement the count to zero, lock
- * the mutex and return true. Otherwise, return false.
- */
-bool qemu_lockcnt_dec_if_lock(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_lock: lock a QemuLockCnt's mutex.
- * @lockcnt: the lockcnt to operate on
- *
- * Remember that concurrent visits are not blocked unless the count is
- * also zero. You can use qemu_lockcnt_count to check for this inside a
- * critical section.
- */
-void qemu_lockcnt_lock(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_unlock: release a QemuLockCnt's mutex.
- * @lockcnt: the lockcnt to operate on.
- */
-void qemu_lockcnt_unlock(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_inc_and_unlock: combined unlock/increment on a QemuLockCnt.
- * @lockcnt: the lockcnt to operate on.
- *
- * This is the same as
- *
- * qemu_lockcnt_unlock(lockcnt);
- * qemu_lockcnt_inc(lockcnt);
- *
- * but more efficient.
- */
-void qemu_lockcnt_inc_and_unlock(QemuLockCnt *lockcnt);
-
-/**
- * qemu_lockcnt_count: query a LockCnt's count.
- * @lockcnt: the lockcnt to query.
- *
- * Note that the count can change at any time. Still, while the
- * lockcnt is locked, one can usefully check whether the count
- * is non-zero.
- */
-unsigned qemu_lockcnt_count(QemuLockCnt *lockcnt);
-
#endif
@@ -25,6 +25,7 @@
*/
#include "qemu/osdep.h"
+#include "qemu/lockcnt.h"
#include "qemu/thread.h"
#include "qemu/main-loop.h"
#include "hw/core/cpu.h"
@@ -24,6 +24,7 @@
#include "sysemu/hw_accel.h"
#include "qemu/log.h"
#include "qemu/main-loop.h"
+#include "qemu/lockcnt.h"
#include "exec/log.h"
#include "exec/gdbstub.h"
#include "sysemu/tcg.h"
@@ -17,6 +17,7 @@
#include "block/block.h"
#include "block/thread-pool.h"
#include "qemu/main-loop.h"
+#include "qemu/lockcnt.h"
#include "qemu/rcu.h"
#include "qemu/rcu_queue.h"
#include "qemu/sockets.h"
@@ -18,6 +18,7 @@
#include "qemu/osdep.h"
#include "block/block.h"
#include "qemu/main-loop.h"
+#include "qemu/lockcnt.h"
#include "qemu/queue.h"
#include "qemu/sockets.h"
#include "qapi/error.h"
@@ -30,6 +30,7 @@
#include "block/graph-lock.h"
#include "qemu/main-loop.h"
#include "qemu/atomic.h"
+#include "qemu/lockcnt.h"
#include "qemu/rcu_queue.h"
#include "block/raw-aio.h"
#include "qemu/coroutine_int.h"
@@ -5,6 +5,7 @@
#include "qemu/osdep.h"
#include <sys/epoll.h>
+#include "qemu/lockcnt.h"
#include "qemu/rcu_queue.h"
#include "aio-posix.h"
@@ -7,6 +7,7 @@
* Paolo Bonzini <pbonzini@redhat.com>
*/
#include "qemu/osdep.h"
+#include "qemu/lockcnt.h"
#include "qemu/thread.h"
#include "qemu/atomic.h"
#include "trace.h"