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author | Kevin Wolf <kwolf@redhat.com> | 2011-06-30 17:56:46 +0200 |
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committer | Kevin Wolf <kwolf@redhat.com> | 2011-08-02 15:53:40 +0200 |
commit | b96e92470ab4a87268e8b174602eaea6c508003b (patch) | |
tree | 04cb3ff62f9f130bfc691541b7e17bd41ac5e534 /qemu-coroutine.h | |
parent | f9f05dc58c50d19ad762e6c1ce6b5def9814a4ed (diff) | |
download | hqemu-b96e92470ab4a87268e8b174602eaea6c508003b.zip hqemu-b96e92470ab4a87268e8b174602eaea6c508003b.tar.gz |
coroutines: Locks
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'qemu-coroutine.h')
-rw-r--r-- | qemu-coroutine.h | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/qemu-coroutine.h b/qemu-coroutine.h index 08255c7..2f2fd95 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 */ |