[Qemu-devel] [PATCH] eventfd: making it rhread safe

[Alexey Kardashevskiy <aik@ozlabs.ru>]

QEMU uses IO handlers to run select() in the main loop. The handlers list is managed by qemu_set_fd_handler() helper which works fine when called from the main thread as it is called not when select() is waiting.

However sometime we need to update the handlers list from another thread. For that the main loop's select() needs to be restarted with the updated list.

The patch adds the qemu_notify_event() call to interrupt select() and make wrapping code to restart select() with the updated IO handlers list.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

---
 iohandler.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/iohandler.c b/iohandler.c
index 3c74de6..dea4355 100644
--- a/iohandler.c
+++ b/iohandler.c
@@ -77,6 +77,7 @@ int qemu_set_fd_handler2(int fd,
         ioh->fd_write = fd_write;
         ioh->opaque = opaque;
         ioh->deleted = 0;
+        qemu_notify_event();
     }
     return 0;
 }
-- 
1.7.10