aboutsummaryrefslogtreecommitdiff
path: root/block
diff options
context:
space:
mode:
Diffstat (limited to 'block')
-rw-r--r--block/graph-lock.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/block/graph-lock.c b/block/graph-lock.c
index 259a7a0bde..2490926c90 100644
--- a/block/graph-lock.c
+++ b/block/graph-lock.c
@@ -30,8 +30,10 @@ BdrvGraphLock graph_lock;
/* Protects the list of aiocontext and orphaned_reader_count */
static QemuMutex aio_context_list_lock;
+#if 0
/* Written and read with atomic operations. */
static int has_writer;
+#endif
/*
* A reader coroutine could move from an AioContext to another.
@@ -88,6 +90,7 @@ void unregister_aiocontext(AioContext *ctx)
g_free(ctx->bdrv_graph);
}
+#if 0
static uint32_t reader_count(void)
{
BdrvGraphRWlock *brdv_graph;
@@ -105,10 +108,17 @@ static uint32_t reader_count(void)
assert((int32_t)rd >= 0);
return rd;
}
+#endif
void bdrv_graph_wrlock(void)
{
GLOBAL_STATE_CODE();
+ /*
+ * TODO Some callers hold an AioContext lock when this is called, which
+ * causes deadlocks. Reenable once the AioContext locking is cleaned up (or
+ * AioContext locks are gone).
+ */
+#if 0
assert(!qatomic_read(&has_writer));
/* Make sure that constantly arriving new I/O doesn't cause starvation */
@@ -139,11 +149,13 @@ void bdrv_graph_wrlock(void)
} while (reader_count() >= 1);
bdrv_drain_all_end();
+#endif
}
void bdrv_graph_wrunlock(void)
{
GLOBAL_STATE_CODE();
+#if 0
QEMU_LOCK_GUARD(&aio_context_list_lock);
assert(qatomic_read(&has_writer));
@@ -155,10 +167,13 @@ void bdrv_graph_wrunlock(void)
/* Wake up all coroutine that are waiting to read the graph */
qemu_co_enter_all(&reader_queue, &aio_context_list_lock);
+#endif
}
void coroutine_fn bdrv_graph_co_rdlock(void)
{
+ /* TODO Reenable when wrlock is reenabled */
+#if 0
BdrvGraphRWlock *bdrv_graph;
bdrv_graph = qemu_get_current_aio_context()->bdrv_graph;
@@ -223,10 +238,12 @@ void coroutine_fn bdrv_graph_co_rdlock(void)
qemu_co_queue_wait(&reader_queue, &aio_context_list_lock);
}
}
+#endif
}
void coroutine_fn bdrv_graph_co_rdunlock(void)
{
+#if 0
BdrvGraphRWlock *bdrv_graph;
bdrv_graph = qemu_get_current_aio_context()->bdrv_graph;
@@ -249,6 +266,7 @@ void coroutine_fn bdrv_graph_co_rdunlock(void)
if (qatomic_read(&has_writer)) {
aio_wait_kick();
}
+#endif
}
void bdrv_graph_rdlock_main_loop(void)
@@ -266,13 +284,19 @@ void bdrv_graph_rdunlock_main_loop(void)
void assert_bdrv_graph_readable(void)
{
/* reader_count() is slow due to aio_context_list_lock lock contention */
+ /* TODO Reenable when wrlock is reenabled */
+#if 0
#ifdef CONFIG_DEBUG_GRAPH_LOCK
assert(qemu_in_main_thread() || reader_count());
#endif
+#endif
}
void assert_bdrv_graph_writable(void)
{
assert(qemu_in_main_thread());
+ /* TODO Reenable when wrlock is reenabled */
+#if 0
assert(qatomic_read(&has_writer));
+#endif
}