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123 lines
3.3 KiB
C
123 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Test that poll handlers are not re-entrant in nested aio_poll()
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*
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* Copyright Red Hat
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*
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* Poll handlers are usually level-triggered. That means they continue firing
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* until the condition is reset (e.g. a virtqueue becomes empty). If a poll
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* handler calls nested aio_poll() before the condition is reset, then infinite
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* recursion occurs.
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*
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* aio_poll() is supposed to prevent this by disabling poll handlers in nested
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* aio_poll() calls. This test case checks that this is indeed what happens.
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*/
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#include "qemu/osdep.h"
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#include "block/aio.h"
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#include "qapi/error.h"
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typedef struct {
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AioContext *ctx;
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/* This is the EventNotifier that drives the test */
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EventNotifier poll_notifier;
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/* This EventNotifier is only used to wake aio_poll() */
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EventNotifier dummy_notifier;
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bool nested;
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} TestData;
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static void io_read(EventNotifier *notifier)
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{
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event_notifier_test_and_clear(notifier);
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}
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static bool io_poll_true(void *opaque)
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{
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return true;
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}
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static bool io_poll_false(void *opaque)
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{
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return false;
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}
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static void io_poll_ready(EventNotifier *notifier)
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{
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TestData *td = container_of(notifier, TestData, poll_notifier);
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g_assert(!td->nested);
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td->nested = true;
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/* Wake the following nested aio_poll() call */
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event_notifier_set(&td->dummy_notifier);
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/* This nested event loop must not call io_poll()/io_poll_ready() */
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g_assert(aio_poll(td->ctx, true));
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td->nested = false;
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}
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/* dummy_notifier never triggers */
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static void io_poll_never_ready(EventNotifier *notifier)
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{
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g_assert_not_reached();
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}
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static void test(void)
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{
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TestData td = {
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.ctx = aio_context_new(&error_abort),
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};
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qemu_set_current_aio_context(td.ctx);
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/* Enable polling */
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aio_context_set_poll_params(td.ctx, 1000000, 2, 2, &error_abort);
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/*
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* The GSource is unused but this has the side-effect of changing the fdmon
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* that AioContext uses.
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*/
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aio_get_g_source(td.ctx);
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/* Make the event notifier active (set) right away */
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event_notifier_init(&td.poll_notifier, 1);
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aio_set_event_notifier(td.ctx, &td.poll_notifier,
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io_read, io_poll_true, io_poll_ready);
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/* This event notifier will be used later */
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event_notifier_init(&td.dummy_notifier, 0);
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aio_set_event_notifier(td.ctx, &td.dummy_notifier,
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io_read, io_poll_false, io_poll_never_ready);
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/* Consume aio_notify() */
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g_assert(!aio_poll(td.ctx, false));
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/*
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* Run the io_read() handler. This has the side-effect of activating
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* polling in future aio_poll() calls.
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*/
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g_assert(aio_poll(td.ctx, true));
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/* The second time around the io_poll()/io_poll_ready() handler runs */
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g_assert(aio_poll(td.ctx, true));
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/* Run io_poll()/io_poll_ready() one more time to show it keeps working */
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g_assert(aio_poll(td.ctx, true));
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aio_set_event_notifier(td.ctx, &td.dummy_notifier, NULL, NULL, NULL);
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aio_set_event_notifier(td.ctx, &td.poll_notifier, NULL, NULL, NULL);
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event_notifier_cleanup(&td.dummy_notifier);
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event_notifier_cleanup(&td.poll_notifier);
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aio_context_unref(td.ctx);
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}
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int main(int argc, char **argv)
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{
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g_test_init(&argc, &argv, NULL);
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g_test_add_func("/nested-aio-poll", test);
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return g_test_run();
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}
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