From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:50220) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qy3Ap-0007i1-3H for qemu-devel@nongnu.org; Mon, 29 Aug 2011 10:50:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Qy3Aj-0000VH-WB for qemu-devel@nongnu.org; Mon, 29 Aug 2011 10:50:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13727) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qy3Aj-0000V9-Me for qemu-devel@nongnu.org; Mon, 29 Aug 2011 10:50:45 -0400 From: Kevin Wolf Date: Mon, 29 Aug 2011 16:53:09 +0200 Message-Id: <1314629618-8308-2-git-send-email-kwolf@redhat.com> In-Reply-To: <1314629618-8308-1-git-send-email-kwolf@redhat.com> References: <1314629618-8308-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH 01/30] coroutine: Add CoRwlock support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: anthony@codemonkey.ws Cc: kwolf@redhat.com, qemu-devel@nongnu.org From: "Aneesh Kumar K.V" Signed-off-by: Aneesh Kumar K.V Signed-off-by: Kevin Wolf --- qemu-coroutine-lock.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ qemu-coroutine.h | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 76 insertions(+), 0 deletions(-) diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c index a80f437..2a385a3 100644 --- a/qemu-coroutine-lock.c +++ b/qemu-coroutine-lock.c @@ -115,3 +115,47 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex) trace_qemu_co_mutex_unlock_return(mutex, self); } + +void qemu_co_rwlock_init(CoRwlock *lock) +{ + memset(lock, 0, sizeof(*lock)); + qemu_co_queue_init(&lock->queue); +} + +void qemu_co_rwlock_rdlock(CoRwlock *lock) +{ + while (lock->writer) { + qemu_co_queue_wait(&lock->queue); + } + lock->reader++; +} + +void qemu_co_rwlock_unlock(CoRwlock *lock) +{ + assert(qemu_in_coroutine()); + if (lock->writer) { + lock->writer = false; + while (!qemu_co_queue_empty(&lock->queue)) { + /* + * Wakeup every body. This will include some + * writers too. + */ + qemu_co_queue_next(&lock->queue); + } + } else { + lock->reader--; + assert(lock->reader >= 0); + /* Wakeup only one waiting writer */ + if (!lock->reader) { + qemu_co_queue_next(&lock->queue); + } + } +} + +void qemu_co_rwlock_wrlock(CoRwlock *lock) +{ + while (lock->writer || lock->reader) { + qemu_co_queue_wait(&lock->queue); + } + lock->writer = true; +} diff --git a/qemu-coroutine.h b/qemu-coroutine.h index 2f2fd95..b8fc4f4 100644 --- a/qemu-coroutine.h +++ b/qemu-coroutine.h @@ -156,4 +156,36 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex); */ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex); +typedef struct CoRwlock { + bool writer; + int reader; + CoQueue queue; +} CoRwlock; + +/** + * Initialises a CoRwlock. This must be called before any other operation + * is used on the CoRwlock + */ +void qemu_co_rwlock_init(CoRwlock *lock); + +/** + * Read locks the CoRwlock. If the lock cannot be taken immediately because + * of a parallel writer, control is transferred to the caller of the current + * coroutine. + */ +void qemu_co_rwlock_rdlock(CoRwlock *lock); + +/** + * Write Locks the mutex. If the lock cannot be taken immediately because + * of a parallel reader, control is transferred to the caller of the current + * coroutine. + */ +void qemu_co_rwlock_wrlock(CoRwlock *lock); + +/** + * Unlocks the read/write lock and schedules the next coroutine that was + * waiting for this lock to be run. + */ +void qemu_co_rwlock_unlock(CoRwlock *lock); + #endif /* QEMU_COROUTINE_H */ -- 1.7.6