[PATCH v15 09/19] scsi: sd: Add a unit test for sd_cmp_sector()

[Bart Van Assche <bvanassche@acm.org>]

Make it easier to test sd_cmp_sector() by adding a unit test for this
function.

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/Kconfig   |  5 +++
 drivers/scsi/sd.c      |  4 ++
 drivers/scsi/sd_test.c | 86 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 drivers/scsi/sd_test.c

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 2e57afdbbc4d..ba2b81ddd7f8 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -237,6 +237,11 @@ config SCSI_ERROR_TEST
 	depends on SCSI && KUNIT
 	default KUNIT_ALL_TESTS
 
+config SD_TEST
+	tristate "sd.c unit tests" if !KUNIT_ALL_TESTS
+	depends on SCSI && BLK_DEV_SD && KUNIT
+	default KUNIT_ALL_TESTS
+
 menu "SCSI Transports"
 	depends on SCSI
 
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 63bb01ddadde..d52ea605ada8 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -4141,3 +4141,7 @@ void sd_print_result(const struct scsi_disk *sdkp, const char *msg, int result)
 			  "%s: Result: hostbyte=0x%02x driverbyte=%s\n",
 			  msg, host_byte(result), "DRIVER_OK");
 }
+
+#ifdef CONFIG_SD_TEST
+#include "sd_test.c"
+#endif
diff --git a/drivers/scsi/sd_test.c b/drivers/scsi/sd_test.c
new file mode 100644
index 000000000000..b9c3d2bf311e
--- /dev/null
+++ b/drivers/scsi/sd_test.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2023 Google LLC
+ */
+#include <kunit/test.h>
+#include <linux/cleanup.h>
+#include <linux/list_sort.h>
+#include <linux/slab.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_driver.h>
+#include "sd.h"
+
+#define ALLOC(type, ...)					\
+	({							\
+		type *obj;					\
+		obj = kmalloc(sizeof(*obj), GFP_KERNEL);	\
+		if (obj)					\
+			*obj = (type){ __VA_ARGS__ };		\
+		obj;						\
+	})
+
+#define ALLOC_Q(...) ALLOC(struct request_queue, __VA_ARGS__)
+
+#define ALLOC_CMD(...) ALLOC(struct rq_and_cmd, __VA_ARGS__)
+
+struct rq_and_cmd {
+	struct request rq;
+	struct scsi_cmnd cmd;
+};
+
+/*
+ * Verify that sd_cmp_sector() does what it is expected to do.
+ */
+static void test_sd_cmp_sector(struct kunit *test)
+{
+	struct request_queue *q1 __free(kfree) =
+		ALLOC_Q(.limits.use_zone_write_lock = true);
+	struct request_queue *q2 __free(kfree) =
+		ALLOC_Q(.limits.use_zone_write_lock = false);
+	struct rq_and_cmd *cmd1 __free(kfree) = ALLOC_CMD(.rq = {
+								  .q = q1,
+								  .__sector = 7,
+							  });
+	struct rq_and_cmd *cmd2 __free(kfree) = ALLOC_CMD(.rq = {
+								  .q = q1,
+								  .__sector = 5,
+							  });
+	struct rq_and_cmd *cmd3 __free(kfree) = ALLOC_CMD(.rq = {
+								  .q = q2,
+								  .__sector = 7,
+							  });
+	struct rq_and_cmd *cmd4 __free(kfree) = ALLOC_CMD(.rq = {
+								  .q = q2,
+								  .__sector = 5,
+							  });
+	LIST_HEAD(cmd_list);
+
+	list_add_tail(&cmd1->cmd.eh_entry, &cmd_list);
+	list_add_tail(&cmd2->cmd.eh_entry, &cmd_list);
+	list_add_tail(&cmd3->cmd.eh_entry, &cmd_list);
+	list_add_tail(&cmd4->cmd.eh_entry, &cmd_list);
+	KUNIT_EXPECT_EQ(test, list_count_nodes(&cmd_list), 4);
+	list_sort(NULL, &cmd_list, sd_cmp_sector);
+	KUNIT_EXPECT_EQ(test, list_count_nodes(&cmd_list), 4);
+	KUNIT_EXPECT_PTR_EQ(test, cmd_list.next, &cmd4->cmd.eh_entry);
+	KUNIT_EXPECT_PTR_EQ(test, cmd_list.next->next, &cmd3->cmd.eh_entry);
+	KUNIT_EXPECT_PTR_EQ(test, cmd_list.next->next->next,
+			    &cmd1->cmd.eh_entry);
+	KUNIT_EXPECT_PTR_EQ(test, cmd_list.next->next->next->next,
+			    &cmd2->cmd.eh_entry);
+}
+
+static struct kunit_case sd_test_cases[] = {
+	KUNIT_CASE(test_sd_cmp_sector),
+	{}
+};
+
+static struct kunit_suite sd_test_suite = {
+	.name = "sd",
+	.test_cases = sd_test_cases,
+};
+kunit_test_suite(sd_test_suite);
+
+MODULE_DESCRIPTION("SCSI disk (sd) driver unit tests");
+MODULE_AUTHOR("Bart Van Assche");
+MODULE_LICENSE("GPL");