async: aio_context_new(): Handle event_notifier_init failure
On a system with a low limit of open files the initialization
of the event notifier could fail and QEMU exits without printing any
error information to the user.
The problem can be easily reproduced by enforcing a low limit of open
files and start QEMU with enough I/O threads to hit this limit.
The same problem raises, without the creation of I/O threads, while
QEMU initializes the main event loop by enforcing an even lower limit of
open files.
This commit adds an error message on failure:
# qemu [...] -object iothread,id=iothread0 -object iothread,id=iothread1
qemu: Failed to initialize event notifier: Too many open files in system
Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/async.c b/async.c
index a99e7f6..6e1b282 100644
--- a/async.c
+++ b/async.c
@@ -289,18 +289,24 @@
aio_notify(opaque);
}
-AioContext *aio_context_new(void)
+AioContext *aio_context_new(Error **errp)
{
+ int ret;
AioContext *ctx;
ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
+ ret = event_notifier_init(&ctx->notifier, false);
+ if (ret < 0) {
+ g_source_destroy(&ctx->source);
+ error_setg_errno(errp, -ret, "Failed to initialize event notifier");
+ return NULL;
+ }
+ aio_set_event_notifier(ctx, &ctx->notifier,
+ (EventNotifierHandler *)
+ event_notifier_test_and_clear);
ctx->pollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
ctx->thread_pool = NULL;
qemu_mutex_init(&ctx->bh_lock);
rfifolock_init(&ctx->lock, aio_rfifolock_cb, ctx);
- event_notifier_init(&ctx->notifier, false);
- aio_set_event_notifier(ctx, &ctx->notifier,
- (EventNotifierHandler *)
- event_notifier_test_and_clear);
timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
return ctx;
