Tests: Asynchronous iSCSI read test

Dispatch a number of READ10 requests simultaneously, and await all
responses.

The iscsi-support test helper functions are currently all synchronous,
so this test mostly uses the bare libiscsi API. As new async tests are
added, we can make a more informed decision on which boilerplate code
can be split out.

Signed-off-by: David Disseldorp <ddiss@suse.de>

test-tool/Makefile.am

@@ -221,7 +221,8 @@ iscsi_test_cu_SOURCES = iscsi-test-cu.c \
 	test_writeverify16_residuals.c \
 	test_multipathio_simple.c \
 	test_multipathio_reset.c \
-	test_multipathio_compareandwrite.c
+	test_multipathio_compareandwrite.c \
+	test_async_read.c
 
 endif
 

test-tool/iscsi-test-cu.c

@@ -227,6 +227,7 @@ static CU_TestInfo tests_read10[] = {
         { (char *)"ZeroBlocks", test_read10_0blocks },
         { (char *)"ReadProtect", test_read10_rdprotect },
         { (char *)"DpoFua", test_read10_dpofua },
+        { (char *)"Async", test_async_read },
         CU_TEST_INFO_NULL
 };
 

test-tool/iscsi-test-cu.h

@@ -145,6 +145,7 @@ void test_read10_rdprotect(void);
 void test_read10_dpofua(void);
 void test_read10_residuals(void);
 void test_read10_invalid(void);
+void test_async_read(void);
 
 void test_read12_simple(void);
 void test_read12_beyond_eol(void);

test-tool/test_async_read.c

@@ -0,0 +1,119 @@
+/*
+   Copyright (C) SUSE LINUX GmbH 2016
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <signal.h>
+#include <poll.h>
+
+#include <CUnit/CUnit.h>
+
+#include "iscsi.h"
+#include "scsi-lowlevel.h"
+#include "iscsi-support.h"
+#include "iscsi-test-cu.h"
+#include "iscsi-multipath.h"
+
+struct tests_async_read_state {
+	uint32_t dispatched;
+	uint32_t completed;
+	uint32_t prev_cmdsn;
+};
+
+static void
+test_async_read_cb(struct iscsi_context *iscsi __attribute__((unused)),
+		   int status, void *command_data, void *private_data)
+{
+	struct scsi_task *atask = command_data;
+	struct tests_async_read_state *state = private_data;
+
+	state->completed++;
+	logging(LOG_VERBOSE, "READ10 completed: %d of %d (CmdSN=%d)",
+		state->completed, state->dispatched, atask->cmdsn);
+	CU_ASSERT_NOT_EQUAL(status, SCSI_STATUS_CHECK_CONDITION);
+
+	if ((state->completed > 1) && (atask->cmdsn != state->prev_cmdsn + 1)) {
+		logging(LOG_VERBOSE,
+			"out of order completion (CmdSN=%d, prev=%d)",
+			atask->cmdsn, state->prev_cmdsn);
+	}
+	state->prev_cmdsn = atask->cmdsn;
+
+	scsi_free_scsi_task(atask);
+}
+
+void
+test_async_read(void)
+{
+	int i, ret;
+	struct tests_async_read_state state = { 0 };
+	int blocksize = 512;
+	int blocks_per_io = 8;
+	int num_ios = 1000;
+	/* IOs in flight concurrently, so need a buffer large enough for all */
+	unsigned char buf[blocksize * blocks_per_io * num_ios];
+
+	CHECK_FOR_DATALOSS;
+	CHECK_FOR_SBC;
+	if (sd->iscsi_ctx == NULL) {
+                CU_PASS("[SKIPPED] Non-iSCSI");
+		return;
+	}
+
+	if (maximum_transfer_length
+	 && (maximum_transfer_length < (blocks_per_io * num_ios))) {
+		CU_PASS("[SKIPPED] device too small for async_read test");
+		return;
+	}
+
+	memset(buf, 0, blocksize * blocks_per_io * num_ios);
+
+	for (i = 0; i < num_ios; i++) {
+		uint32_t lba = i * blocks_per_io;
+		struct scsi_task *atask;
+
+		atask = scsi_cdb_read10(lba, blocks_per_io * blocksize,
+				       blocksize, 0, 0, 0, 0, 0);
+		CU_ASSERT_PTR_NOT_NULL_FATAL(atask);
+
+		ret = scsi_task_add_data_in_buffer(atask,
+						   blocks_per_io * blocksize,
+						   &buf[lba * blocksize]);
+		CU_ASSERT_EQUAL(ret, 0);
+
+		ret = iscsi_scsi_command_async(sd->iscsi_ctx, sd->iscsi_lun,
+					       atask, test_async_read_cb, NULL,
+					       &state);
+		CU_ASSERT_EQUAL(ret, 0);
+
+		state.dispatched++;
+		logging(LOG_VERBOSE, "READ10 dispatched: %d of %d (cmdsn=%d)",
+			state.dispatched, num_ios, atask->cmdsn);
+	}
+
+	while (state.completed < state.dispatched) {
+		struct pollfd pfd;
+
+		pfd.fd = iscsi_get_fd(sd->iscsi_ctx);
+		pfd.events = iscsi_which_events(sd->iscsi_ctx);
+
+		ret = poll(&pfd, 1, -1);
+		CU_ASSERT_NOT_EQUAL(ret, -1);
+
+		ret = iscsi_service(sd->iscsi_ctx, pfd.revents);
+		CU_ASSERT_EQUAL(ret, 0);
+	}
+}