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Date: Sun, 18 Dec 2011 01:07:51 +0200
From: Andriy Gapon <avg@FreeBSD.org>
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Subject: RB_NOSYNC -> no device_shutdown ?
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I look at the following code:

static void
module_init(void *arg)
{

        sx_init(&modules_sx, "module subsystem sx lock");
        TAILQ_INIT(&modules);
        EVENTHANDLER_REGISTER(shutdown_final, module_shutdown, NULL,
            SHUTDOWN_PRI_DEFAULT);
}

SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, 0);

static void
module_shutdown(void *arg1, int arg2)
{
        module_t mod;

        if (arg2 & RB_NOSYNC)
                return;
        mtx_lock(&Giant);
        MOD_SLOCK;
        TAILQ_FOREACH_REVERSE(mod, &modules, modulelist, link)
                MOD_EVENT(mod, MOD_SHUTDOWN);
        MOD_SUNLOCK;
        mtx_unlock(&Giant);
}

and wonder why RB_NOSYNC is overloaded to mean that no
MOD_SHUTDOWN/device_shutdown cleanup should be done?

-- 
Andriy Gapon