[PATCH 04/18] async: Register/unregister aiocontext in graph lock list

[Kevin Wolf <kwolf@redhat.com>]

From: Emanuele Giuseppe Esposito <eesposit@redhat.com>

Add/remove the AioContext in aio_context_list in graph-lock.c when it is
created/destroyed. This allows using the graph locking operations from
this AioContext.

In order to allow linking util/async.c with binaries that don't include
the block layer, introduce stubs for (un)register_aiocontext().

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 stubs/graph-lock.c | 10 ++++++++++
 util/async.c       |  4 ++++
 stubs/meson.build  |  1 +
 3 files changed, 15 insertions(+)
 create mode 100644 stubs/graph-lock.c

diff --git a/stubs/graph-lock.c b/stubs/graph-lock.c
new file mode 100644
index 0000000000..177aa0a8ba
--- /dev/null
+++ b/stubs/graph-lock.c
@@ -0,0 +1,10 @@
+#include "qemu/osdep.h"
+#include "block/graph-lock.h"
+
+void register_aiocontext(AioContext *ctx)
+{
+}
+
+void unregister_aiocontext(AioContext *ctx)
+{
+}
diff --git a/util/async.c b/util/async.c
index 63434ddae4..14d63b3091 100644
--- a/util/async.c
+++ b/util/async.c
@@ -27,6 +27,7 @@
 #include "qapi/error.h"
 #include "block/aio.h"
 #include "block/thread-pool.h"
+#include "block/graph-lock.h"
 #include "qemu/main-loop.h"
 #include "qemu/atomic.h"
 #include "qemu/rcu_queue.h"
@@ -376,6 +377,7 @@ aio_ctx_finalize(GSource     *source)
     qemu_rec_mutex_destroy(&ctx->lock);
     qemu_lockcnt_destroy(&ctx->list_lock);
     timerlistgroup_deinit(&ctx->tlg);
+    unregister_aiocontext(ctx);
     aio_context_destroy(ctx);
 }
 
@@ -574,6 +576,8 @@ AioContext *aio_context_new(Error **errp)
     ctx->thread_pool_min = 0;
     ctx->thread_pool_max = THREAD_POOL_MAX_THREADS_DEFAULT;
 
+    register_aiocontext(ctx);
+
     return ctx;
 fail:
     g_source_destroy(&ctx->source);
diff --git a/stubs/meson.build b/stubs/meson.build
index c96a74f095..981585cbdf 100644
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -13,6 +13,7 @@ stub_ss.add(files('error-printf.c'))
 stub_ss.add(files('fdset.c'))
 stub_ss.add(files('gdbstub.c'))
 stub_ss.add(files('get-vm-name.c'))
+stub_ss.add(files('graph-lock.c'))
 if linux_io_uring.found()
   stub_ss.add(files('io_uring.c'))
 endif
-- 
2.38.1