mt/bdev.c/bdev_ut.c

/*-
 *   BSD LICENSE
 *
 *   Copyright (c) Intel Corporation.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "spdk_cunit.h"

#include "lib/test_env.c"
#include "lib/ut_multithread.c"

/* HACK: disable VTune integration so the unit test doesn't need VTune headers and libs to build */
#undef SPDK_CONFIG_VTUNE

#include "bdev/bdev.c"

#define BDEV_UT_NUM_THREADS 3

DEFINE_STUB_V(spdk_scsi_nvme_translate, (const struct spdk_bdev_io *bdev_io,
		int *sc, int *sk, int *asc, int *ascq));

struct ut_bdev {
	struct spdk_bdev	bdev;
	void			*io_target;
};

struct ut_bdev_channel {
	TAILQ_HEAD(, spdk_bdev_io)	outstanding_io;
	uint32_t			outstanding_cnt;
	uint32_t			avail_cnt;
};

int g_io_device;
struct ut_bdev g_bdev;
struct spdk_bdev_desc *g_desc;
bool g_teardown_done = false;
bool g_get_io_channel = true;
bool g_create_ch = true;

static int
stub_create_ch(void *io_device, void *ctx_buf)
{
	struct ut_bdev_channel *ch = ctx_buf;

	if (g_create_ch == false) {
		return -1;
	}

	TAILQ_INIT(&ch->outstanding_io);
	ch->outstanding_cnt = 0;
	/*
	 * When avail gets to 0, the submit_request function will return ENOMEM.
	 *  Most tests to not want ENOMEM to occur, so by default set this to a
	 *  big value that won't get hit.  The ENOMEM tests can then override this
	 *  value to something much smaller to induce ENOMEM conditions.
	 */
	ch->avail_cnt = 2048;
	return 0;
}

static void
stub_destroy_ch(void *io_device, void *ctx_buf)
{
}

static struct spdk_io_channel *
stub_get_io_channel(void *ctx)
{
	struct ut_bdev *ut_bdev = ctx;

	if (g_get_io_channel == true) {
		return spdk_get_io_channel(ut_bdev->io_target);
	} else {
		return NULL;
	}
}

static int
stub_destruct(void *ctx)
{
	return 0;
}

static void
stub_submit_request(struct spdk_io_channel *_ch, struct spdk_bdev_io *bdev_io)
{
	struct ut_bdev_channel *ch = spdk_io_channel_get_ctx(_ch);

	if (bdev_io->type == SPDK_BDEV_IO_TYPE_RESET) {
		struct spdk_bdev_io *io;

		while (!TAILQ_EMPTY(&ch->outstanding_io)) {
			io = TAILQ_FIRST(&ch->outstanding_io);
			TAILQ_REMOVE(&ch->outstanding_io, io, module_link);
			ch->outstanding_cnt--;
			spdk_bdev_io_complete(io, SPDK_BDEV_IO_STATUS_FAILED);
			ch->avail_cnt++;
		}
	}

	if (ch->avail_cnt > 0) {
		TAILQ_INSERT_TAIL(&ch->outstanding_io, bdev_io, module_link);
		ch->outstanding_cnt++;
		ch->avail_cnt--;
	} else {
		spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_NOMEM);
	}
}

static uint32_t
stub_complete_io(void *io_target, uint32_t num_to_complete)
{
	struct spdk_io_channel *_ch = spdk_get_io_channel(io_target);
	struct ut_bdev_channel *ch = spdk_io_channel_get_ctx(_ch);
	struct spdk_bdev_io *io;
	bool complete_all = (num_to_complete == 0);
	uint32_t num_completed = 0;

	while (complete_all || num_completed < num_to_complete) {
		if (TAILQ_EMPTY(&ch->outstanding_io)) {
			break;
		}
		io = TAILQ_FIRST(&ch->outstanding_io);
		TAILQ_REMOVE(&ch->outstanding_io, io, module_link);
		ch->outstanding_cnt--;
		spdk_bdev_io_complete(io, SPDK_BDEV_IO_STATUS_SUCCESS);
		ch->avail_cnt++;
		num_completed++;
	}

	spdk_put_io_channel(_ch);
	return num_completed;
}

static struct spdk_bdev_fn_table fn_table = {
	.get_io_channel =	stub_get_io_channel,
	.destruct =		stub_destruct,
	.submit_request =	stub_submit_request,
};

static int
module_init(void)
{
	return 0;
}

static void
module_fini(void)
{
}

SPDK_BDEV_MODULE_REGISTER(bdev_ut, module_init, module_fini, NULL, NULL, NULL)

static void
register_bdev(struct ut_bdev *ut_bdev, char *name, void *io_target)
{
	memset(ut_bdev, 0, sizeof(*ut_bdev));

	ut_bdev->io_target = io_target;
	ut_bdev->bdev.ctxt = ut_bdev;
	ut_bdev->bdev.name = name;
	ut_bdev->bdev.fn_table = &fn_table;
	ut_bdev->bdev.module = SPDK_GET_BDEV_MODULE(bdev_ut);
	ut_bdev->bdev.blocklen = 4096;
	ut_bdev->bdev.blockcnt = 1024;

	spdk_bdev_register(&ut_bdev->bdev);
}

static void
unregister_bdev(struct ut_bdev *ut_bdev)
{
	/* Handle any deferred messages. */
	poll_threads();
	spdk_bdev_unregister(&ut_bdev->bdev, NULL, NULL);
	memset(ut_bdev, 0, sizeof(*ut_bdev));
}

static void
bdev_init_cb(void *done, int rc)
{
	CU_ASSERT(rc == 0);
	*(bool *)done = true;
}

static void
setup_test(void)
{
	bool done = false;

	allocate_threads(BDEV_UT_NUM_THREADS);
	spdk_bdev_initialize(bdev_init_cb, &done);
	spdk_io_device_register(&g_io_device, stub_create_ch, stub_destroy_ch,
				sizeof(struct ut_bdev_channel));
	register_bdev(&g_bdev, "ut_bdev", &g_io_device);
	spdk_bdev_open(&g_bdev.bdev, true, NULL, NULL, &g_desc);
}

static void
finish_cb(void *cb_arg)
{
	g_teardown_done = true;
}

static void
teardown_test(void)
{
	g_teardown_done = false;
	spdk_bdev_close(g_desc);
	g_desc = NULL;
	unregister_bdev(&g_bdev);
	spdk_io_device_unregister(&g_io_device, NULL);
	spdk_bdev_finish(finish_cb, NULL);
	poll_threads();
	CU_ASSERT(g_teardown_done == true);
	g_teardown_done = false;
	free_threads();
}

static void
basic(void)
{
	setup_test();

	set_thread(0);

	g_get_io_channel = false;
	g_ut_threads[0].ch = spdk_bdev_get_io_channel(g_desc);
	CU_ASSERT(g_ut_threads[0].ch == NULL);

	g_get_io_channel = true;
	g_create_ch = false;
	g_ut_threads[0].ch = spdk_bdev_get_io_channel(g_desc);
	CU_ASSERT(g_ut_threads[0].ch == NULL);

	g_get_io_channel = true;
	g_create_ch = true;
	g_ut_threads[0].ch = spdk_bdev_get_io_channel(g_desc);
	CU_ASSERT(g_ut_threads[0].ch != NULL);
	spdk_put_io_channel(g_ut_threads[0].ch);

	teardown_test();
}

static void
poller_run_done(void *ctx)
{
	bool	*poller_run = ctx;

	*poller_run = true;
}

static void
poller_run_times_done(void *ctx)
{
	int	*poller_run_times = ctx;

	(*poller_run_times)++;
}

static void
basic_poller(void)
{
	struct spdk_poller	*poller = NULL;
	bool			poller_run = false;
	int			poller_run_times = 0;

	setup_test();

	set_thread(0);
	reset_time();
	/* Register a poller with no-wait time and test execution */
	poller = spdk_poller_register(poller_run_done, &poller_run, 0);
	CU_ASSERT(poller != NULL);

	poll_threads();
	CU_ASSERT(poller_run == true);

	spdk_poller_unregister(&poller);
	CU_ASSERT(poller == NULL);

	/* Register a poller with 1000us wait time and test single execution */
	poller_run = false;
	poller = spdk_poller_register(poller_run_done, &poller_run, 1000);
	CU_ASSERT(poller != NULL);

	poll_threads();
	CU_ASSERT(poller_run == false);

	increment_time(1000);
	poll_threads();
	CU_ASSERT(poller_run == true);

	reset_time();
	poller_run = false;
	poll_threads();
	CU_ASSERT(poller_run == false);

	increment_time(1000);
	poll_threads();
	CU_ASSERT(poller_run == true);

	spdk_poller_unregister(&poller);
	CU_ASSERT(poller == NULL);

	reset_time();
	/* Register a poller with 1000us wait time and test multiple execution */
	poller = spdk_poller_register(poller_run_times_done, &poller_run_times, 1000);
	CU_ASSERT(poller != NULL);

	poll_threads();
	CU_ASSERT(poller_run_times == 0);

	increment_time(1000);
	poll_threads();
	CU_ASSERT(poller_run_times == 1);

	poller_run_times = 0;
	increment_time(2000);
	poll_threads();
	CU_ASSERT(poller_run_times == 2);

	spdk_poller_unregister(&poller);
	CU_ASSERT(poller == NULL);

	teardown_test();
}

static void
reset_done(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
{
	bool *done = cb_arg;

	CU_ASSERT(success == true);
	*done = true;
	spdk_bdev_free_io(bdev_io);
}

static void
put_channel_during_reset(void)
{
	struct spdk_io_channel *io_ch;
	bool done = false;

	setup_test();

	set_thread(0);
	io_ch = spdk_bdev_get_io_channel(g_desc);
	CU_ASSERT(io_ch != NULL);

	/*
	 * Start a reset, but then put the I/O channel before
	 *  the deferred messages for the reset get a chance to
	 *  execute.
	 */
	spdk_bdev_reset(g_desc, io_ch, reset_done, &done);
	spdk_put_io_channel(io_ch);
	poll_threads();
	stub_complete_io(g_bdev.io_target, 0);

	teardown_test();
}

static void
aborted_reset_done(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
{
	enum spdk_bdev_io_status *status = cb_arg;

	*status = success ? SPDK_BDEV_IO_STATUS_SUCCESS : SPDK_BDEV_IO_STATUS_FAILED;
	spdk_bdev_free_io(bdev_io);
}

static void
aborted_reset(void)
{
	struct spdk_io_channel *io_ch[2];
	enum spdk_bdev_io_status status1, status2;

	setup_test();

	set_thread(0);
	io_ch[0] = spdk_bdev_get_io_channel(g_desc);
	CU_ASSERT(io_ch[0] != NULL);
	spdk_bdev_reset(g_desc, io_ch[0], aborted_reset_done, &status1);
	poll_threads();
	CU_ASSERT(g_bdev.bdev.reset_in_progress != NULL);

	/*
	 * First reset has been submitted on ch0.  Now submit a second
	 *  reset on ch1 which will get queued since there is already a
	 *  reset in progress.
	 */
	set_thread(1);
	io_ch[1] = spdk_bdev_get_io_channel(g_desc);
	CU_ASSERT(io_ch[1] != NULL);
	spdk_bdev_reset(g_desc, io_ch[1], aborted_reset_done, &status2);
	poll_threads();
	CU_ASSERT(g_bdev.bdev.reset_in_progress != NULL);

	/*
	 * Now destroy ch1.  This will abort the queued reset.  Check that
	 *  the second reset was completed with failed status.  Also check
	 *  that bdev->reset_in_progress != NULL, since the original reset
	 *  has not been completed yet.  This ensures that the bdev code is
	 *  correctly noticing that the failed reset is *not* the one that
	 *  had been submitted to the bdev module.
	 */
	set_thread(1);
	spdk_put_io_channel(io_ch[1]);
	poll_threads();
	CU_ASSERT(status2 == SPDK_BDEV_IO_STATUS_FAILED);
	CU_ASSERT(g_bdev.bdev.reset_in_progress != NULL);

	/*
	 * Now complete the first reset, verify that it completed with SUCCESS
	 *  status and that bdev->reset_in_progress is also set back to NULL.
	 */
	set_thread(0);
	spdk_put_io_channel(io_ch[0]);
	stub_complete_io(g_bdev.io_target, 0);
	poll_threads();
	CU_ASSERT(status1 == SPDK_BDEV_IO_STATUS_SUCCESS);
	CU_ASSERT(g_bdev.bdev.reset_in_progress == NULL);

	teardown_test();
}

static void
io_during_reset_done(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
{
	enum spdk_bdev_io_status *status = cb_arg;

	*status = success ? SPDK_BDEV_IO_STATUS_SUCCESS : SPDK_BDEV_IO_STATUS_FAILED;
	spdk_bdev_free_io(bdev_io);
}

static void
io_during_reset(void)
{
	struct spdk_io_channel *io_ch[2];
	struct spdk_bdev_channel *bdev_ch[2];
	enum spdk_bdev_io_status status0, status1, status_reset;
	int rc;

	setup_test();

	/*
	 * First test normal case - submit an I/O on each of two channels (with no resets)
	 *  and verify they complete successfully.
	 */
	set_thread(0);
	io_ch[0] = spdk_bdev_get_io_channel(g_desc);
	bdev_ch[0] = spdk_io_channel_get_ctx(io_ch[0]);
	CU_ASSERT(bdev_ch[0]->flags == 0);
	status0 = SPDK_BDEV_IO_STATUS_PENDING;
	rc = spdk_bdev_read_blocks(g_desc, io_ch[0], NULL, 0, 1, io_during_reset_done, &status0);
	CU_ASSERT(rc == 0);

	set_thread(1);
	io_ch[1] = spdk_bdev_get_io_channel(g_desc);
	bdev_ch[1] = spdk_io_channel_get_ctx(io_ch[1]);
	CU_ASSERT(bdev_ch[1]->flags == 0);
	status1 = SPDK_BDEV_IO_STATUS_PENDING;
	rc = spdk_bdev_read_blocks(g_desc, io_ch[1], NULL, 0, 1, io_during_reset_done, &status1);
	CU_ASSERT(rc == 0);

	poll_threads();
	CU_ASSERT(status0 == SPDK_BDEV_IO_STATUS_PENDING);
	CU_ASSERT(status1 == SPDK_BDEV_IO_STATUS_PENDING);

	set_thread(0);
	stub_complete_io(g_bdev.io_target, 0);
	CU_ASSERT(status0 == SPDK_BDEV_IO_STATUS_SUCCESS);

	set_thread(1);
	stub_complete_io(g_bdev.io_target, 0);
	CU_ASSERT(status1 == SPDK_BDEV_IO_STATUS_SUCCESS);

	/*
	 * Now submit a reset, and leave it pending while we submit I/O on two different
	 *  channels.  These I/O should be failed by the bdev layer since the reset is in
	 *  progress.
	 */
	set_thread(0);
	status_reset = SPDK_BDEV_IO_STATUS_PENDING;
	rc = spdk_bdev_reset(g_desc, io_ch[0], io_during_reset_done, &status_reset);
	CU_ASSERT(rc == 0);

	CU_ASSERT(bdev_ch[0]->flags == 0);
	CU_ASSERT(bdev_ch[1]->flags == 0);
	poll_threads();
	CU_ASSERT(bdev_ch[0]->flags == BDEV_CH_RESET_IN_PROGRESS);
	CU_ASSERT(bdev_ch[1]->flags == BDEV_CH_RESET_IN_PROGRESS);

	set_thread(0);
	status0 = SPDK_BDEV_IO_STATUS_PENDING;
	rc = spdk_bdev_read_blocks(g_desc, io_ch[0], NULL, 0, 1, io_during_reset_done, &status0);
	CU_ASSERT(rc == 0);

	set_thread(1);
	status1 = SPDK_BDEV_IO_STATUS_PENDING;
	rc = spdk_bdev_read_blocks(g_desc, io_ch[1], NULL, 0, 1, io_during_reset_done, &status1);
	CU_ASSERT(rc == 0);

	/*
	 * A reset is in progress so these read I/O should complete with failure.  Note that we
	 *  need to poll_threads() since I/O completed inline have their completion deferred.
	 */
	poll_threads();
	CU_ASSERT(status_reset == SPDK_BDEV_IO_STATUS_PENDING);
	CU_ASSERT(status0 == SPDK_BDEV_IO_STATUS_FAILED);
	CU_ASSERT(status1 == SPDK_BDEV_IO_STATUS_FAILED);

	/*
	 * Complete the reset
	 */
	set_thread(0);
	stub_complete_io(g_bdev.io_target, 0);

	/*
	 * Only poll thread 0. We should not get a completion.
	 */
	poll_thread(0);
	CU_ASSERT(status_reset == SPDK_BDEV_IO_STATUS_PENDING);

	/*
	 * Poll both thread 0 and 1 so the messages can propagate and we
	 * get a completion.
	 */
	poll_threads();
	CU_ASSERT(status_reset == SPDK_BDEV_IO_STATUS_SUCCESS);

	spdk_put_io_channel(io_ch[0]);
	set_thread(1);
	spdk_put_io_channel(io_ch[1]);
	poll_threads();

	teardown_test();
}

static void
enomem_done(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
{
	enum spdk_bdev_io_status *status = cb_arg;

	*status = success ? SPDK_BDEV_IO_STATUS_SUCCESS : SPDK_BDEV_IO_STATUS_FAILED;
	spdk_bdev_free_io(bdev_io);
}

static uint32_t
bdev_io_tailq_cnt(bdev_io_tailq_t *tailq)
{
	struct spdk_bdev_io *io;
	uint32_t cnt = 0;

	TAILQ_FOREACH(io, tailq, link) {
		cnt++;
	}

	return cnt;
}

static void
enomem(void)
{
	struct spdk_io_channel *io_ch;
	struct spdk_bdev_channel *bdev_ch;
	struct spdk_bdev_module_channel *module_ch;
	struct ut_bdev_channel *ut_ch;
	const uint32_t IO_ARRAY_SIZE = 64;
	const uint32_t AVAIL = 20;
	enum spdk_bdev_io_status status[IO_ARRAY_SIZE], status_reset;
	uint32_t nomem_cnt, i;
	struct spdk_bdev_io *first_io;
	int rc;

	setup_test();

	set_thread(0);
	io_ch = spdk_bdev_get_io_channel(g_desc);
	bdev_ch = spdk_io_channel_get_ctx(io_ch);
	module_ch = bdev_ch->module_ch;
	ut_ch = spdk_io_channel_get_ctx(bdev_ch->channel);
	ut_ch->avail_cnt = AVAIL;

	/* First submit a number of IOs equal to what the channel can support. */
	for (i = 0; i < AVAIL; i++) {
		status[i] = SPDK_BDEV_IO_STATUS_PENDING;
		rc = spdk_bdev_read_blocks(g_desc, io_ch, NULL, 0, 1, enomem_done, &status[i]);
		CU_ASSERT(rc == 0);
	}
	CU_ASSERT(TAILQ_EMPTY(&module_ch->nomem_io));

	/*
	 * Next, submit one additional I/O.  This one should fail with ENOMEM and then go onto
	 *  the enomem_io list.
	 */
	status[AVAIL] = SPDK_BDEV_IO_STATUS_PENDING;
	rc = spdk_bdev_read_blocks(g_desc, io_ch, NULL, 0, 1, enomem_done, &status[AVAIL]);
	CU_ASSERT(rc == 0);
	SPDK_CU_ASSERT_FATAL(!TAILQ_EMPTY(&module_ch->nomem_io));
	first_io = TAILQ_FIRST(&module_ch->nomem_io);

	/*
	 * Now submit a bunch more I/O.  These should all fail with ENOMEM and get queued behind
	 *  the first_io above.
	 */
	for (i = AVAIL + 1; i < IO_ARRAY_SIZE; i++) {
		status[i] = SPDK_BDEV_IO_STATUS_PENDING;
		rc = spdk_bdev_read_blocks(g_desc, io_ch, NULL, 0, 1, enomem_done, &status[i]);
		CU_ASSERT(rc == 0);
	}

	/* Assert that first_io is still at the head of the list. */
	CU_ASSERT(TAILQ_FIRST(&module_ch->nomem_io) == first_io);
	CU_ASSERT(bdev_io_tailq_cnt(&module_ch->nomem_io) == (IO_ARRAY_SIZE - AVAIL));
	nomem_cnt = bdev_io_tailq_cnt(&module_ch->nomem_io);
	CU_ASSERT(module_ch->nomem_threshold == (AVAIL - NOMEM_THRESHOLD_COUNT));

	/*
	 * Complete 1 I/O only.  The key check here is bdev_io_tailq_cnt - this should not have
	 *  changed since completing just 1 I/O should not trigger retrying the queued nomem_io
	 *  list.
	 */
	stub_complete_io(g_bdev.io_target, 1);
	CU_ASSERT(bdev_io_tailq_cnt(&module_ch->nomem_io) == nomem_cnt);

	/*
	 * Complete enough I/O to hit the nomem_theshold.  This should trigger retrying nomem_io,
	 *  and we should see I/O get resubmitted to the test bdev module.
	 */
	stub_complete_io(g_bdev.io_target, NOMEM_THRESHOLD_COUNT - 1);
	CU_ASSERT(bdev_io_tailq_cnt(&module_ch->nomem_io) < nomem_cnt);
	nomem_cnt = bdev_io_tailq_cnt(&module_ch->nomem_io);

	/* Complete 1 I/O only.  This should not trigger retrying the queued nomem_io. */
	stub_complete_io(g_bdev.io_target, 1);
	CU_ASSERT(bdev_io_tailq_cnt(&module_ch->nomem_io) == nomem_cnt);

	/*
	 * Send a reset and confirm that all I/O are completed, including the ones that
	 *  were queued on the nomem_io list.
	 */
	status_reset = SPDK_BDEV_IO_STATUS_PENDING;
	rc = spdk_bdev_reset(g_desc, io_ch, enomem_done, &status_reset);
	poll_threads();
	CU_ASSERT(rc == 0);
	/* This will complete the reset. */
	stub_complete_io(g_bdev.io_target, 0);

	CU_ASSERT(bdev_io_tailq_cnt(&module_ch->nomem_io) == 0);
	CU_ASSERT(module_ch->io_outstanding == 0);

	spdk_put_io_channel(io_ch);
	poll_threads();
	teardown_test();
}

static void
enomem_multi_bdev(void)
{
	struct spdk_io_channel *io_ch;
	struct spdk_bdev_channel *bdev_ch;
	struct spdk_bdev_module_channel *module_ch;
	struct ut_bdev_channel *ut_ch;
	const uint32_t IO_ARRAY_SIZE = 64;
	const uint32_t AVAIL = 20;
	enum spdk_bdev_io_status status[IO_ARRAY_SIZE];
	uint32_t i;
	struct ut_bdev *second_bdev;
	struct spdk_bdev_desc *second_desc;
	struct spdk_bdev_channel *second_bdev_ch;
	struct spdk_io_channel *second_ch;
	int rc;

	setup_test();

	/* Register second bdev with the same io_target  */
	second_bdev = calloc(1, sizeof(*second_bdev));
	SPDK_CU_ASSERT_FATAL(second_bdev != NULL);
	register_bdev(second_bdev, "ut_bdev2", g_bdev.io_target);
	spdk_bdev_open(&second_bdev->bdev, true, NULL, NULL, &second_desc);

	set_thread(0);
	io_ch = spdk_bdev_get_io_channel(g_desc);
	bdev_ch = spdk_io_channel_get_ctx(io_ch);
	module_ch = bdev_ch->module_ch;
	ut_ch = spdk_io_channel_get_ctx(bdev_ch->channel);
	ut_ch->avail_cnt = AVAIL;

	second_ch = spdk_bdev_get_io_channel(second_desc);
	second_bdev_ch = spdk_io_channel_get_ctx(second_ch);
	SPDK_CU_ASSERT_FATAL(module_ch == second_bdev_ch->module_ch);

	/* Saturate io_target through bdev A. */
	for (i = 0; i < AVAIL; i++) {
		status[i] = SPDK_BDEV_IO_STATUS_PENDING;
		rc = spdk_bdev_read_blocks(g_desc, io_ch, NULL, 0, 1, enomem_done, &status[i]);
		CU_ASSERT(rc == 0);
	}
	CU_ASSERT(TAILQ_EMPTY(&module_ch->nomem_io));

	/*
	 * Now submit I/O through the second bdev. This should fail with ENOMEM
	 * and then go onto the nomem_io list.
	 */
	status[AVAIL] = SPDK_BDEV_IO_STATUS_PENDING;
	rc = spdk_bdev_read_blocks(second_desc, second_ch, NULL, 0, 1, enomem_done, &status[AVAIL]);
	CU_ASSERT(rc == 0);
	SPDK_CU_ASSERT_FATAL(!TAILQ_EMPTY(&module_ch->nomem_io));

	/* Complete first bdev's I/O. This should retry sending second bdev's nomem_io */
	stub_complete_io(g_bdev.io_target, AVAIL);

	SPDK_CU_ASSERT_FATAL(TAILQ_EMPTY(&module_ch->nomem_io));
	CU_ASSERT(module_ch->io_outstanding == 1);

	/* Now complete our retried I/O  */
	stub_complete_io(g_bdev.io_target, 1);
	SPDK_CU_ASSERT_FATAL(module_ch->io_outstanding == 0);

	spdk_put_io_channel(io_ch);
	spdk_put_io_channel(second_ch);
	spdk_bdev_close(second_desc);
	unregister_bdev(second_bdev);
	free(second_bdev);
	poll_threads();
	teardown_test();
}

int
main(int argc, char **argv)
{
	CU_pSuite	suite = NULL;
	unsigned int	num_failures;

	if (CU_initialize_registry() != CUE_SUCCESS) {
		return CU_get_error();
	}

	suite = CU_add_suite("bdev", NULL, NULL);
	if (suite == NULL) {
		CU_cleanup_registry();
		return CU_get_error();
	}

	if (
		CU_add_test(suite, "basic", basic) == NULL ||
		CU_add_test(suite, "basic_poller", basic_poller) == NULL ||
		CU_add_test(suite, "put_channel_during_reset", put_channel_during_reset) == NULL ||
		CU_add_test(suite, "aborted_reset", aborted_reset) == NULL ||
		CU_add_test(suite, "io_during_reset", io_during_reset) == NULL ||
		CU_add_test(suite, "enomem", enomem) == NULL ||
		CU_add_test(suite, "enomem_multi_bdev", enomem_multi_bdev) == NULL
	) {
		CU_cleanup_registry();
		return CU_get_error();
	}

	CU_basic_set_mode(CU_BRM_VERBOSE);
	CU_basic_run_tests();
	num_failures = CU_get_number_of_failures();
	CU_cleanup_registry();
	return num_failures;
}