[01/16] aio: introduce aio_context_in_iothread

Commit Message

Paolo Bonzini Feb. 8, 2016, 4:14 p.m. UTC

This will be used by the synchronous I/O helpers, to choose between
aio_poll or QemuEvent.

Signed-off-by: Paolo Bonzini <[e-mail]>
---
 include/block/aio.h | 7 +++++++
 iothread.c          | 9 +++++++++
 2 files changed, 16 insertions(+)

Patch

diff --git a/include/block/aio.h b/include/block/aio.h
index e086e3b..9434665 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -435,6 +435,13 @@  static inline bool aio_node_check(AioContext *ctx, bool is_external)
 }
 
 /**
+ * @ctx: the aio context
+ *
+ * Return whether we are running in the I/O thread that manages @ctx.
+ */
+bool aio_context_in_iothread(AioContext *ctx);
+
+/**
  * aio_context_setup:
  * @ctx: the aio context
  *
diff --git a/iothread.c b/iothread.c
index f183d38..8d40bb0 100644
--- a/iothread.c
+++ b/iothread.c
@@ -20,6 +20,7 @@ 
 #include "qmp-commands.h"
 #include "qemu/error-report.h"
 #include "qemu/rcu.h"
+#include "qemu/main-loop.h"
 
 typedef ObjectClass IOThreadClass;
 
@@ -28,6 +29,13 @@  typedef ObjectClass IOThreadClass;
 #define IOTHREAD_CLASS(klass) \
    OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD)
 
+static __thread IOThread *my_iothread;
+
+bool aio_context_in_iothread(AioContext *ctx)
+{
+    return ctx == (my_iothread ? my_iothread->ctx : qemu_get_aio_context());
+}
+
 static void *iothread_run(void *opaque)
 {
     IOThread *iothread = opaque;
@@ -35,6 +43,7 @@  static void *iothread_run(void *opaque)
 
     rcu_register_thread();
 
+    my_iothread = iothread;
     qemu_mutex_lock(&iothread->init_done_lock);
     iothread->thread_id = qemu_get_thread_id();
     qemu_cond_signal(&iothread->init_done_cond);