@@ -127,6 +127,8 @@ static bool fdmon_epoll_try_enable(AioContext *ctx)
bool fdmon_epoll_try_upgrade(AioContext *ctx, unsigned npfd)
{
+ bool ok;
+
if (ctx->epollfd < 0) {
return false;
}
@@ -136,14 +138,23 @@ bool fdmon_epoll_try_upgrade(AioContext *ctx, unsigned npfd)
return false;
}
- if (npfd >= EPOLL_ENABLE_THRESHOLD) {
- if (fdmon_epoll_try_enable(ctx)) {
- return true;
- } else {
- fdmon_epoll_disable(ctx);
- }
+ if (npfd < EPOLL_ENABLE_THRESHOLD) {
+ return false;
+ }
+
+ /* The list must not change while we add fds to epoll */
+ if (!qemu_lockcnt_dec_if_lock(&ctx->list_lock)) {
+ return false;
+ }
+
+ ok = fdmon_epoll_try_enable(ctx);
+
+ qemu_lockcnt_inc_and_unlock(&ctx->list_lock);
+
+ if (!ok) {
+ fdmon_epoll_disable(ctx);
}
- return false;
+ return ok;
}
void fdmon_epoll_setup(AioContext *ctx)