[PATCH v4 0/1] block: Add test-iosched scheduler

[PATCH v4 0/1] block: Add test-iosched scheduler

[Maya Erez]

The test scheduler allows testing a block device by dispatching
specific requests according to the test case and declare PASS/FAIL
according to the requests completion error code

Changes in v4:
     - fix test_init_queue definition

Changes in v3:
     - checkpatch error fixes
     - Changes to support the packed commands tests
Changes in v2:
    - Export test-iosched functionality to allow definition of the block device
      tests under the block device layer
    - Add registration of block device tests utilities

Maya Erez (1):
  block: Add test-iosched scheduler

 Documentation/block/test-iosched.txt |   39 ++
 block/Kconfig.iosched                |   11 +
 block/Makefile                       |    1 +
 block/blk-core.c                     |    3 +-
 block/test-iosched.c                 | 1015 ++++++++++++++++++++++++++++++++++
 include/linux/test-iosched.h         |  218 ++++++++
 6 files changed, 1285 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/block/test-iosched.txt
 create mode 100644 block/test-iosched.c
 create mode 100644 include/linux/test-iosched.h

-- 
1.7.3.3
-- 
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

[PATCH v4 1/1] block: Add test-iosched scheduler

[Maya Erez]

The test scheduler allows testing a block device by dispatching
specific requests according to the test case and declare PASS/FAIL
according to the requests completion error code

Signed-off-by: Maya Erez <merez@codeaurora.org>

diff --git a/Documentation/block/test-iosched.txt b/Documentation/block/test-iosched.txt
new file mode 100644
index 0000000..75d8134
--- /dev/null
+++ b/Documentation/block/test-iosched.txt
@@ -0,0 +1,39 @@
+Test IO scheduler
+==================
+
+The test scheduler allows testing a block device by dispatching
+specific requests according to the test case and declare PASS/FAIL
+according to the requests completion error code.
+
+The test IO scheduler implements the no-op scheduler operations, and uses
+them in order to dispatch the non-test requests when no test is running.
+This will allow to keep a normal FS operation in parallel to the test
+capability.
+The test IO scheduler keeps two different queues, one for real-world requests
+(inserted by the FS) and the other for the test requests.
+The test IO scheduler chooses the queue for dispatch requests according to the
+test state (IDLE/RUNNING).
+
+the test IO scheduler is compiled by default as a dynamic module and enabled
+only if CONFIG_DEBUG_FS is defined.
+
+Each block device test utility that would like to use the test-iosched test
+services, should register as a blk_dev_test_type and supply an init and exit
+callbacks. Those callback are called upon selection (or removal) of the
+test-iosched as the active scheduler. From that point the block device test
+can start a test and supply its own callbacks for preparing, running, result
+checking and cleanup of the test.
+
+Each test is exposed via debugfs and can be triggered by writing to
+the debugfs file. In order to add a new test one should expose a new debugfs
+file for the new test.
+
+Selecting IO schedulers
+-----------------------
+Refer to Documentation/block/switching-sched.txt for information on
+selecting an io scheduler on a per-device basis.
+
+
+May 10 2012, maya Erez <merez@codeaurora.org>
+
+
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 421bef9..af3d6a3 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -12,6 +12,17 @@ config IOSCHED_NOOP
 	  that do their own scheduling and require only minimal assistance from
 	  the kernel.
 
+config IOSCHED_TEST
+	tristate "Test I/O scheduler"
+	depends on DEBUG_FS
+	default m
+	---help---
+	  The test I/O scheduler is a duplicate of the noop scheduler with
+	  addition of test utlity.
+	  It allows testing a block device by dispatching specific requests
+	  according to the test case and declare PASS/FAIL according to the
+	  requests completion error code.
+
 config IOSCHED_DEADLINE
 	tristate "Deadline I/O scheduler"
 	default y
diff --git a/block/Makefile b/block/Makefile
index 39b76ba..436b220 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_BLK_DEV_THROTTLING)	+= blk-throttle.o
 obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o
 obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
 obj-$(CONFIG_IOSCHED_CFQ)	+= cfq-iosched.o
+obj-$(CONFIG_IOSCHED_TEST)	+= test-iosched.o
 
 obj-$(CONFIG_BLOCK_COMPAT)	+= compat_ioctl.o
 obj-$(CONFIG_BLK_DEV_INTEGRITY)	+= blk-integrity.o
diff --git a/block/blk-core.c b/block/blk-core.c
index 5639a3d..54ea4da 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1072,8 +1072,6 @@ struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
 {
 	struct request *rq;
 
-	BUG_ON(rw != READ && rw != WRITE);
-
 	spin_lock_irq(q->queue_lock);
 	if (gfp_mask & __GFP_WAIT)
 		rq = get_request_wait(q, rw, NULL);
@@ -1406,6 +1404,7 @@ void init_request_from_bio(struct request *req, struct bio *bio)
 	req->ioprio = bio_prio(bio);
 	blk_rq_bio_prep(req->q, req, bio);
 }
+EXPORT_SYMBOL(init_request_from_bio);
 
 void blk_queue_bio(struct request_queue *q, struct bio *bio)
 {
diff --git a/block/test-iosched.c b/block/test-iosched.c
new file mode 100644
index 0000000..e4b89d2
--- /dev/null
+++ b/block/test-iosched.c
@@ -0,0 +1,1015 @@
+
+/* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * The test scheduler allows to test the block device by dispatching
+ * specific requests according to the test case and declare PASS/FAIL
+ * according to the requests completion error code.
+ * Each test is exposed via debugfs and can be triggered by writing to
+ * the debugfs file.
+ *
+ */
+
+/* elevator test iosched */
+#include <linux/blkdev.h>
+#include <linux/elevator.h>
+#include <linux/bio.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <linux/test-iosched.h>
+#include <linux/delay.h>
+#include "blk.h"
+
+#define MODULE_NAME "test-iosched"
+#define WR_RD_START_REQ_ID 1234
+#define UNIQUE_START_REQ_ID 5678
+#define TIMEOUT_TIMER_MS 40000
+#define TEST_MAX_TESTCASE_ROUNDS 15
+
+#define test_pr_debug(fmt, args...) pr_debug("%s: "fmt"\n", MODULE_NAME, args)
+#define test_pr_info(fmt, args...) pr_info("%s: "fmt"\n", MODULE_NAME, args)
+#define test_pr_err(fmt, args...) pr_err("%s: "fmt"\n", MODULE_NAME, args)
+
+static DEFINE_SPINLOCK(blk_dev_test_list_lock);
+static LIST_HEAD(blk_dev_test_list);
+static struct test_data *ptd;
+
+/* Get the request after `test_rq' in the test requests list */
+static struct test_request *
+latter_test_request(struct request_queue *q,
+				 struct test_request *test_rq)
+{
+	struct test_data *td = q->elevator->elevator_data;
+
+	if (test_rq->queuelist.next == &td->test_queue)
+		return NULL;
+	return list_entry(test_rq->queuelist.next, struct test_request,
+			  queuelist);
+}
+
+/**
+ * test_iosched_get_req_queue() - returns the request queue
+ * served by the scheduler
+ */
+struct request_queue *test_iosched_get_req_queue(void)
+{
+	if (!ptd)
+		return NULL;
+
+	return ptd->req_q;
+}
+EXPORT_SYMBOL(test_iosched_get_req_queue);
+
+/**
+ * test_iosched_mark_test_completion() - Wakeup the debugfs
+ * thread, waiting on the test completion
+ */
+void test_iosched_mark_test_completion(void)
+{
+	if (!ptd)
+		return;
+
+	ptd->test_state = TEST_COMPLETED;
+	wake_up(&ptd->wait_q);
+}
+EXPORT_SYMBOL(test_iosched_mark_test_completion);
+
+/* Check if all the queued test requests were completed */
+static void check_test_completion(void)
+{
+	struct test_request *test_rq;
+	struct request *rq;
+
+	list_for_each_entry(test_rq, &ptd->test_queue, queuelist) {
+		rq = test_rq->rq;
+		if (!test_rq->req_completed)
+			return;
+	}
+
+	test_pr_info("%s: Test is completed", __func__);
+
+	test_iosched_mark_test_completion();
+}
+
+/*
+ * A callback to be called per bio completion.
+ * Frees the bio memory.
+ */
+static void end_test_bio(struct bio *bio, int err)
+{
+	if (err)
+		clear_bit(BIO_UPTODATE, &bio->bi_flags);
+
+	bio_put(bio);
+}
+
+/*
+ * A callback to be called per request completion.
+ * the request memory is not freed here, will be freed later after the test
+ * results checking.
+ */
+static void end_test_req(struct request *rq, int err)
+{
+	struct test_request *test_rq;
+
+	test_rq = (struct test_request *)rq->elv.priv[0];
+	BUG_ON(!test_rq);
+
+	test_pr_info("%s: request %d completed, err=%d",
+	       __func__, test_rq->req_id, err);
+
+	test_rq->req_completed = 1;
+	test_rq->req_result = err;
+
+	check_test_completion();
+}
+
+/**
+ * test_iosched_add_unique_test_req() - Create and queue a non
+ * read/write request (such as FLUSH/DISCRAD/SANITIZE).
+ * @is_err_expcted:	A flag to indicate if this request
+ *			should succeed or not
+ * @req_unique:		The type of request to add
+ * @start_sec:		start address of the first bio
+ * @nr_sects:		number of sectors in the request
+ * @end_req_io:		specific completion callback. When not
+ *			set, the defaulcallback will be used
+ */
+int test_iosched_add_unique_test_req(int is_err_expcted,
+			enum req_unique_type req_unique,
+			int start_sec, int nr_sects, rq_end_io_fn *end_req_io)
+{
+	struct bio *bio;
+	struct request *rq;
+	int rw_flags;
+	struct test_request *test_rq;
+
+	if (!ptd)
+		return -ENODEV;
+
+	bio = bio_alloc(GFP_KERNEL, 0);
+	if (!bio) {
+		test_pr_err("%s: Failed to allocate a bio", __func__);
+		return -ENODEV;
+	}
+	bio_get(bio);
+	bio->bi_end_io = end_test_bio;
+
+	switch (req_unique) {
+	case REQ_UNIQUE_FLUSH:
+		bio->bi_rw = WRITE_FLUSH;
+		break;
+	case REQ_UNIQUE_DISCARD:
+		bio->bi_rw = REQ_WRITE | REQ_DISCARD;
+		bio->bi_size = nr_sects << 9;
+		bio->bi_sector = start_sec;
+		break;
+	default:
+		test_pr_err("%s: Invalid request type %d", __func__,
+			    req_unique);
+		bio_put(bio);
+		return -ENODEV;
+	}
+
+	rw_flags = bio_data_dir(bio);
+	if (bio->bi_rw & REQ_SYNC)
+		rw_flags |= REQ_SYNC;
+
+	rq = blk_get_request(ptd->req_q, rw_flags, GFP_KERNEL);
+	if (!rq) {
+		test_pr_err("%s: Failed to allocate a request", __func__);
+		bio_put(bio);
+		return -ENODEV;
+	}
+
+	init_request_from_bio(rq, bio);
+	if (end_req_io)
+		rq->end_io = end_req_io;
+	else
+		rq->end_io = end_test_req;
+
+	test_rq = kzalloc(sizeof(struct test_request), GFP_KERNEL);
+	if (!test_rq) {
+		test_pr_err("%s: Failed to allocate a test request", __func__);
+		bio_put(bio);
+		blk_put_request(rq);
+		return -ENODEV;
+	}
+	test_rq->req_completed = 0;
+	test_rq->req_result = -1;
+	test_rq->rq = rq;
+	test_rq->is_err_expected = is_err_expcted;
+	rq->elv.priv[0] = (void *)test_rq;
+	test_rq->req_id = ptd->unique_next_req_id++;
+
+	test_pr_debug(
+		"%s: added request %d to the test requests list, type = %d",
+		__func__, test_rq->req_id, req_unique);
+
+	list_add_tail(&test_rq->queuelist, &ptd->test_queue);
+
+	return 0;
+}
+EXPORT_SYMBOL(test_iosched_add_unique_test_req);
+
+/*
+ * Get a pattern to be filled in the request data buffer.
+ * If the pattern used is (-1) the buffer will be filled with sequential
+ * numbers
+ */
+static void fill_buf_with_pattern(int *buf, int num_bytes, int pattern)
+{
+	int i = 0;
+	int num_of_dwords = num_bytes/sizeof(int);
+
+	if (pattern == TEST_NO_PATTERN)
+		return;
+
+	/* num_bytes should be aligned to sizeof(int) */
+	BUG_ON((num_bytes % sizeof(int)) != 0);
+
+	if (pattern == TEST_PATTERN_SEQUENTIAL) {
+		for (i = 0; i < num_of_dwords; i++)
+			buf[i] = i;
+	} else {
+		for (i = 0; i < num_of_dwords; i++)
+			buf[i] = pattern;
+	}
+}
+
+/**
+ * test_iosched_add_wr_rd_test_req() - Create and queue a
+ * read/write request.
+ * @is_err_expcted:	A flag to indicate if this request
+ *			should succeed or not
+ * @direction:		READ/WRITE
+ * @start_sec:		start address of the first bio
+ * @num_bios:		number of BIOs to be allocated for the
+ *			request
+ * @pattern:		A pattern, to be written into the write
+ *			requests data buffer. In case of READ
+ *			request, the given pattern is kept as
+ *			the expected pattern. The expected
+ *			pattern will be compared in the test
+ *			check result function. If no comparisson
+ *			is required, set pattern to
+ *			TEST_NO_PATTERN.
+ * @end_req_io:		specific completion callback. When not
+ *			set,the default callback will be used
+ *
+ * This function allocates the test request and the block
+ * request and calls blk_rq_map_kern which allocates the
+ * required BIO. The allocated test request and the block
+ * request memory is freed at the end of the test and the
+ * allocated BIO memory is freed by end_test_bio.
+ */
+int test_iosched_add_wr_rd_test_req(int is_err_expcted,
+		      int direction, int start_sec,
+		      int num_bios, int pattern, rq_end_io_fn *end_req_io)
+{
+	struct request *rq = NULL;
+	struct test_request *test_rq = NULL;
+	int rw_flags = 0;
+	int buf_size = 0;
+	int ret = 0, i = 0;
+	unsigned int *bio_ptr = NULL;
+	struct bio *bio = NULL;
+
+	if (!ptd)
+		return -ENODEV;
+
+	rw_flags = direction;
+
+	rq = blk_get_request(ptd->req_q, rw_flags, GFP_KERNEL);
+	if (!rq) {
+		test_pr_err("%s: Failed to allocate a request", __func__);
+		return -ENODEV;
+	}
+
+	test_rq = kzalloc(sizeof(struct test_request), GFP_KERNEL);
+	if (!test_rq) {
+		test_pr_err("%s: Failed to allocate test request", __func__);
+		blk_put_request(rq);
+		return -ENODEV;
+	}
+
+	buf_size = sizeof(unsigned int) * BIO_U32_SIZE * num_bios;
+	test_rq->bios_buffer = kzalloc(buf_size, GFP_KERNEL);
+	if (!test_rq->bios_buffer) {
+		test_pr_err("%s: Failed to allocate the data buf", __func__);
+		goto err;
+	}
+	test_rq->buf_size = buf_size;
+
+	if (direction == WRITE)
+		fill_buf_with_pattern(test_rq->bios_buffer,
+						   buf_size, pattern);
+	test_rq->wr_rd_data_pattern = pattern;
+
+	bio_ptr = test_rq->bios_buffer;
+	for (i = 0; i < num_bios; ++i) {
+		ret = blk_rq_map_kern(ptd->req_q, rq,
+				      (void *)bio_ptr,
+				      sizeof(unsigned int)*BIO_U32_SIZE,
+				      GFP_KERNEL);
+		if (ret) {
+			test_pr_err("%s: blk_rq_map_kern returned error %d",
+				    __func__, ret);
+			goto err;
+		}
+		bio_ptr += BIO_U32_SIZE;
+	}
+
+	if (end_req_io)
+		rq->end_io = end_req_io;
+	else
+		rq->end_io = end_test_req;
+	rq->__sector = start_sec;
+	rq->cmd_type |= REQ_TYPE_FS;
+
+	if (rq->bio) {
+		rq->bio->bi_sector = start_sec;
+		rq->bio->bi_end_io = end_test_bio;
+		bio = rq->bio;
+		while ((bio = bio->bi_next) != NULL)
+			bio->bi_end_io = end_test_bio;
+	}
+
+	ptd->num_of_write_bios += num_bios;
+	test_rq->req_id = ptd->wr_rd_next_req_id++;
+
+	test_rq->req_completed = 0;
+	test_rq->req_result = -1;
+	test_rq->rq = rq;
+	test_rq->is_err_expected = is_err_expcted;
+	rq->elv.priv[0] = (void *)test_rq;
+
+	test_pr_debug(
+		"%s: added request %d to the test requests list, buf_size=%d",
+		__func__, test_rq->req_id, buf_size);
+
+	list_add_tail(&test_rq->queuelist, &ptd->test_queue);
+
+	return 0;
+err:
+	blk_put_request(rq);
+	kfree(test_rq->bios_buffer);
+	return -ENODEV;
+}
+EXPORT_SYMBOL(test_iosched_add_wr_rd_test_req);
+
+/* Converts the testcase number into a string */
+static char *get_test_case_str(struct test_data *td)
+{
+	if (td->test_info.get_test_case_str_fn)
+		return td->test_info.get_test_case_str_fn(td);
+
+	return "Unknown testcase";
+}
+
+/*
+ * Verify that the test request data buffer includes the expected
+ * pattern
+ */
+static int compare_buffer_to_pattern(struct test_request *test_rq)
+{
+	int i = 0;
+	int num_of_dwords = test_rq->buf_size/sizeof(int);
+
+	/* num_bytes should be aligned to sizeof(int) */
+	BUG_ON((test_rq->buf_size % sizeof(int)) != 0);
+	BUG_ON(test_rq->bios_buffer == NULL);
+
+	if (test_rq->wr_rd_data_pattern == TEST_NO_PATTERN)
+		return 0;
+
+	if (test_rq->wr_rd_data_pattern == TEST_PATTERN_SEQUENTIAL) {
+		for (i = 0; i < num_of_dwords; i++) {
+			if (test_rq->bios_buffer[i] != i) {
+				test_pr_err(
+					"%s: wrong pattern 0x%x in index %d",
+					__func__, test_rq->bios_buffer[i], i);
+				return -EINVAL;
+			}
+		}
+	} else {
+		for (i = 0; i < num_of_dwords; i++) {
+			if (test_rq->bios_buffer[i] !=
+			    test_rq->wr_rd_data_pattern) {
+				test_pr_err(
+					"%s: wrong pattern 0x%x in index %d",
+					__func__, test_rq->bios_buffer[i], i);
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Determine if the test passed or failed.
+ * The function checks the test request completion value and calls
+ * check_testcase_result for result checking that are specific
+ * to a test case.
+ */
+static int check_test_result(struct test_data *td)
+{
+	struct test_request *test_rq;
+	struct request *rq;
+	int res = 0;
+	static int run;
+
+	list_for_each_entry(test_rq, &ptd->test_queue, queuelist) {
+		rq = test_rq->rq;
+		if (!test_rq->req_completed) {
+			test_pr_err("%s: rq %d not completed", __func__,
+				    test_rq->req_id);
+			res = -EINVAL;
+			goto err;
+		}
+
+		if ((test_rq->req_result < 0) && !test_rq->is_err_expected) {
+			test_pr_err(
+				"%s: rq %d completed with err, not as expected",
+				__func__, test_rq->req_id);
+			res = -EINVAL;
+			goto err;
+		}
+		if ((test_rq->req_result == 0) && test_rq->is_err_expected) {
+			test_pr_err("%s: rq %d succeeded, not as expected",
+				    __func__, test_rq->req_id);
+			res = -EINVAL;
+			goto err;
+		}
+		if (rq_data_dir(test_rq->rq) == READ) {
+			res = compare_buffer_to_pattern(test_rq);
+			if (res) {
+				test_pr_err("%s: read pattern not as expected",
+					    __func__);
+				res = -EINVAL;
+				goto err;
+			}
+		}
+	}
+
+	if (td->test_info.check_test_result_fn) {
+		res = td->test_info.check_test_result_fn(td);
+		if (res)
+			goto err;
+	}
+
+	test_pr_info("%s: %s, run# %03d, PASSED",
+			    __func__, get_test_case_str(td), ++run);
+	td->test_result = TEST_PASSED;
+
+	return 0;
+err:
+	test_pr_err("%s: %s, run# %03d, FAILED",
+		    __func__, get_test_case_str(td), ++run);
+	td->test_result = TEST_FAILED;
+	return res;
+}
+
+/* Create and queue the required requests according to the test case */
+static int prepare_test(struct test_data *td)
+{
+	int ret = 0;
+
+	if (td->test_info.prepare_test_fn) {
+		ret = td->test_info.prepare_test_fn(td);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* Run the test */
+static int run_test(struct test_data *td)
+{
+	int ret = 0;
+
+	if (td->test_info.run_test_fn) {
+		ret = td->test_info.run_test_fn(td);
+		return ret;
+	}
+
+	/*
+	 * Set the next_req pointer to the first request in the test requests
+	 * list
+	 */
+	if (!list_empty(&td->test_queue))
+		td->next_req = list_entry(td->test_queue.next,
+					  struct test_request, queuelist);
+	__blk_run_queue(td->req_q);
+
+	return 0;
+}
+
+/* Free the allocated test requests, their requests and BIOs buffer */
+static void free_test_requests(struct test_data *td)
+{
+	struct test_request *test_rq;
+	while (!list_empty(&td->test_queue)) {
+		test_rq = list_entry(td->test_queue.next, struct test_request,
+				     queuelist);
+		list_del_init(&test_rq->queuelist);
+		blk_put_request(test_rq->rq);
+		kfree(test_rq->bios_buffer);
+		kfree(test_rq);
+	}
+}
+
+/*
+ * Do post test operations.
+ * Free the allocated test requests, their requests and BIOs buffer.
+ */
+static int post_test(struct test_data *td)
+{
+	int ret = 0;
+
+	if (td->test_info.post_test_fn)
+		ret = td->test_info.post_test_fn(td);
+
+	ptd->test_info.testcase = 0;
+	ptd->test_state = TEST_IDLE;
+
+	free_test_requests(td);
+
+	return ret;
+}
+
+/*
+ * The timer verifies that the test will be completed even if we don't get
+ * the completion callback for all the requests.
+ */
+static void test_timeout_handler(unsigned long data)
+{
+	struct test_data *td = (struct test_data *)data;
+
+	test_pr_info("%s: TIMEOUT timer expired", __func__);
+	td->test_state = TEST_COMPLETED;
+	wake_up(&td->wait_q);
+	return;
+}
+
+static unsigned int get_timeout_msec(struct test_data *td)
+{
+	if (td->test_info.timeout_msec)
+		return td->test_info.timeout_msec;
+	else
+		return TIMEOUT_TIMER_MS;
+}
+
+/**
+ * test_iosched_start_test() - Prepares and runs the test.
+ * @t_info:	the current test testcase and callbacks
+ *		functions
+ *
+ * The function also checks the test result upon test completion
+ */
+int test_iosched_start_test(struct test_info *t_info)
+{
+	int ret = 0;
+	unsigned timeout_msec;
+	int counter = 0;
+	char *test_name = NULL;
+
+	if (!ptd)
+		return -ENODEV;
+
+	if (!t_info) {
+		ptd->test_result = TEST_FAILED;
+		return -EINVAL;
+	}
+
+	do {
+		if (ptd->ignore_round)
+			/*
+			 * We ignored the last run due to FS write requests.
+			 * Sleep to allow those requests to be issued
+			 */
+			msleep(2000);
+
+		spin_lock(&ptd->lock);
+
+		if (ptd->test_state != TEST_IDLE) {
+			test_pr_info(
+				"%s: Another test is running, try again later",
+				__func__);
+			return -EINVAL;
+		}
+
+		if (ptd->start_sector == 0) {
+			test_pr_err("%s: Invalid start sector\n. "
+				"User should set the start sector before "
+				"running the test using this command:\n"
+				"echo <START_SECTOR> > "
+				"/<path-to-debugfs>/test-iosched/start_sector",
+			       __func__);
+			ptd->test_result = TEST_FAILED;
+			spin_unlock(&ptd->lock);
+			return -EINVAL;
+		}
+
+		memcpy(&ptd->test_info, t_info, sizeof(struct test_info));
+
+		ptd->next_req = NULL;
+		ptd->test_result = TEST_NO_RESULT;
+		ptd->num_of_write_bios = 0;
+
+		ptd->unique_next_req_id = UNIQUE_START_REQ_ID;
+		ptd->wr_rd_next_req_id = WR_RD_START_REQ_ID;
+
+		ptd->test_state = TEST_RUNNING;
+
+		spin_unlock(&ptd->lock);
+
+		timeout_msec = get_timeout_msec(ptd);
+		mod_timer(&ptd->timeout_timer, jiffies +
+			  msecs_to_jiffies(timeout_msec));
+
+		if (ptd->test_info.get_test_case_str_fn)
+			test_name = ptd->test_info.get_test_case_str_fn(ptd);
+		else
+			test_name = "Unknown testcase";
+		test_pr_info("%s: Starting test %s\n", __func__, test_name);
+
+		ret = prepare_test(ptd);
+		if (ret) {
+			test_pr_err("%s: failed to prepare the test\n",
+				    __func__);
+			goto error;
+		}
+
+		ret = run_test(ptd);
+		if (ret) {
+			test_pr_err("%s: failed to run the test\n", __func__);
+			goto error;
+		}
+
+		test_pr_info("%s: Waiting for the test completion", __func__);
+
+		wait_event(ptd->wait_q, ptd->test_state == TEST_COMPLETED);
+		del_timer_sync(&ptd->timeout_timer);
+
+		if (!ptd->ignore_round) {
+			ret = check_test_result(ptd);
+			if (ret) {
+				test_pr_err("%s: check_test_result failed\n",
+					    __func__);
+				goto error;
+			}
+		} else {
+			test_pr_info(
+			"%s: Round canceled (Got wr reqs in the middle)",
+			__func__);
+		}
+
+		ret = post_test(ptd);
+		if (ret) {
+			test_pr_err("%s: post_test failed\n", __func__);
+			goto error;
+		}
+
+		/*
+		 * Wakeup the queue thread to fetch FS requests that might got
+		 * postponded due to the test
+		 */
+		__blk_run_queue(ptd->req_q);
+
+		if (counter == TEST_MAX_TESTCASE_ROUNDS) {
+			test_pr_info("%s: Too many rounds did not succeed...",
+			     __func__);
+			ptd->test_result = TEST_FAILED;
+		}
+
+	} while ((ptd->ignore_round) && (counter < TEST_MAX_TESTCASE_ROUNDS));
+
+	if (ptd->test_result == TEST_PASSED)
+		return 0;
+	else
+		return -EINVAL;
+
+error:
+	ptd->test_result = TEST_FAILED;
+	ptd->test_info.testcase = 0;
+	post_test(ptd);
+	return ret;
+}
+EXPORT_SYMBOL(test_iosched_start_test);
+
+/**
+ * test_iosched_register() - register a block device test
+ * utility.
+ * @bdt:	the block device test type to register
+ */
+void test_iosched_register(struct blk_dev_test_type *bdt)
+{
+	spin_lock(&blk_dev_test_list_lock);
+	list_add_tail(&bdt->list, &blk_dev_test_list);
+	spin_unlock(&blk_dev_test_list_lock);
+}
+EXPORT_SYMBOL_GPL(test_iosched_register);
+
+/**
+ * test_iosched_unregister() - unregister a block device test
+ * utility.
+ * @bdt:	the block device test type to unregister
+ */
+void test_iosched_unregister(struct blk_dev_test_type *bdt)
+{
+	spin_lock(&blk_dev_test_list_lock);
+	list_del_init(&bdt->list);
+	spin_unlock(&blk_dev_test_list_lock);
+}
+EXPORT_SYMBOL_GPL(test_iosched_unregister);
+
+/**
+ * test_iosched_set_test_result() - Set the test
+ * result(PASS/FAIL)
+ * @test_result:	the test result
+ */
+void test_iosched_set_test_result(int test_result)
+{
+	if (!ptd)
+		return;
+
+	ptd->test_result = test_result;
+}
+EXPORT_SYMBOL(test_iosched_set_test_result);
+
+/**
+ * test_iosched_get_debugfs_tests_root() - returns the root
+ * debugfs directory for the test_iosched tests
+ */
+struct dentry *test_iosched_get_debugfs_tests_root(void)
+{
+	if (!ptd)
+		return NULL;
+
+	return ptd->debug.debug_tests_root;
+}
+EXPORT_SYMBOL(test_iosched_get_debugfs_tests_root);
+
+/**
+ * test_iosched_get_debugfs_utils_root() - returns the root
+ * debugfs directory for the test_iosched utils
+ */
+struct dentry *test_iosched_get_debugfs_utils_root(void)
+{
+	if (!ptd)
+		return NULL;
+
+	return ptd->debug.debug_utils_root;
+}
+EXPORT_SYMBOL(test_iosched_get_debugfs_utils_root);
+
+static int test_debugfs_init(struct test_data *td)
+{
+	td->debug.debug_root = debugfs_create_dir("test-iosched", NULL);
+	if (!td->debug.debug_root)
+		return -ENOENT;
+
+	td->debug.debug_tests_root = debugfs_create_dir("tests",
+							td->debug.debug_root);
+	if (!td->debug.debug_tests_root)
+		goto err;
+
+	td->debug.debug_utils_root = debugfs_create_dir("utils",
+							td->debug.debug_root);
+	if (!td->debug.debug_utils_root)
+		goto err;
+
+	td->debug.debug_test_result = debugfs_create_u32(
+					"test_result",
+					S_IRUGO | S_IWUGO,
+					td->debug.debug_utils_root,
+					&td->test_result);
+	if (!td->debug.debug_test_result)
+		goto err;
+
+	td->debug.start_sector = debugfs_create_u32(
+					"start_sector",
+					S_IRUGO | S_IWUGO,
+					td->debug.debug_utils_root,
+					&td->start_sector);
+	if (!td->debug.start_sector)
+		goto err;
+
+	return 0;
+
+err:
+	debugfs_remove_recursive(td->debug.debug_root);
+	return -ENOENT;
+}
+
+static void test_debugfs_cleanup(struct test_data *td)
+{
+	debugfs_remove_recursive(td->debug.debug_root);
+}
+
+static void print_req(struct request *req)
+{
+	struct bio *bio;
+	struct test_request *test_rq;
+
+	if (!req)
+		return;
+
+	test_rq = (struct test_request *)req->elv.priv[0];
+
+	if (test_rq) {
+		test_pr_debug("%s: Dispatch request %d: "
+			"__data_len=0x%x, __sector=0x%lx, atomic_flags=0x%lx, "
+		       "cmd_flags=0x%x, cmd_len=0x%x, cmd_type=0x%x, "
+		       "nr_phys_segments=%d, num_of_sectors=%d",
+		       __func__, test_rq->req_id, req->__data_len,
+		       (unsigned long)req->__sector,
+		       req->atomic_flags, req->cmd_flags, req->cmd_len,
+		       req->cmd_type,  req->nr_phys_segments,
+		       blk_rq_sectors(req));
+		bio = req->bio;
+		test_pr_debug("%s: bio: bi_size=%d, bi_sector=0x%lx",
+			      __func__, bio->bi_size,
+			      (unsigned long)bio->bi_sector);
+		while ((bio = bio->bi_next) != NULL) {
+			test_pr_debug("%s: bio: bi_size=%d, bi_sector=0x%lx",
+				      __func__, bio->bi_size,
+				      (unsigned long)bio->bi_sector);
+		}
+	}
+}
+
+static void test_merged_requests(struct request_queue *q,
+			 struct request *rq, struct request *next)
+{
+	list_del_init(&next->queuelist);
+}
+
+/*
+ * Dispatch a test request in case there is a running test Otherwise, dispatch
+ * a request that was queued by the FS to keep the card functional.
+ */
+static int test_dispatch_requests(struct request_queue *q, int force)
+{
+	struct test_data *td = q->elevator->elevator_data;
+	struct request *rq = NULL;
+
+	switch (td->test_state) {
+	case TEST_IDLE:
+		if (!list_empty(&td->queue)) {
+			rq = list_entry(td->queue.next, struct request,
+					queuelist);
+			list_del_init(&rq->queuelist);
+			elv_dispatch_sort(q, rq);
+			return 1;
+		}
+		break;
+	case TEST_RUNNING:
+		if (td->next_req) {
+			rq = td->next_req->rq;
+			td->next_req =
+				latter_test_request(td->req_q, td->next_req);
+			if (!rq)
+				return 0;
+			print_req(rq);
+			elv_dispatch_sort(q, rq);
+			return 1;
+		}
+		break;
+	case TEST_COMPLETED:
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+
+static void test_add_request(struct request_queue *q,
+				     struct request *rq)
+{
+	struct test_data *td = q->elevator->elevator_data;
+
+	list_add_tail(&rq->queuelist, &td->queue);
+
+	if (ptd->test_info.ignore_run_due_to_fs_wr_reqs) {
+		if ((rq_data_dir(rq) == WRITE) &&
+		    (td->test_state == TEST_RUNNING)) {
+			test_pr_info(
+				"%s: got WRITE req in the middle of the test",
+				__func__);
+			td->ignore_round = 1;
+		}
+	}
+}
+
+static struct request *
+test_former_request(struct request_queue *q, struct request *rq)
+{
+	struct test_data *td = q->elevator->elevator_data;
+
+	if (rq->queuelist.prev == &td->queue)
+		return NULL;
+	return list_entry(rq->queuelist.prev, struct request, queuelist);
+}
+
+static struct request *
+test_latter_request(struct request_queue *q, struct request *rq)
+{
+	struct test_data *td = q->elevator->elevator_data;
+
+	if (rq->queuelist.next == &td->queue)
+		return NULL;
+	return list_entry(rq->queuelist.next, struct request, queuelist);
+}
+
+static int test_init_queue(struct request_queue *q)
+{
+	struct blk_dev_test_type *__bdt;
+
+	ptd = kmalloc_node(sizeof(struct test_data), GFP_KERNEL,
+			     q->node);
+	if (!ptd) {
+		test_pr_err("%s: failed to allocate test data", __func__);
+		return -ENODEV;
+	}
+	memset((void *)ptd, 0, sizeof(struct test_data));
+	INIT_LIST_HEAD(&ptd->queue);
+	INIT_LIST_HEAD(&ptd->test_queue);
+	init_waitqueue_head(&ptd->wait_q);
+	ptd->req_q = q;
+	q->elevator->elevator_data = ptd;
+
+	setup_timer(&ptd->timeout_timer, test_timeout_handler,
+		    (unsigned long)ptd);
+
+	spin_lock_init(&ptd->lock);
+
+	if (test_debugfs_init(ptd)) {
+		test_pr_err("%s: Failed to create debugfs files", __func__);
+		return -ENODEV;
+	}
+
+	list_for_each_entry(__bdt, &blk_dev_test_list, list)
+		__bdt->init_fn();
+
+	return 0;
+}
+
+static void test_exit_queue(struct elevator_queue *e)
+{
+	struct test_data *td = e->elevator_data;
+	struct blk_dev_test_type *__bdt;
+
+	BUG_ON(!list_empty(&td->queue));
+
+	list_for_each_entry(__bdt, &blk_dev_test_list, list)
+		__bdt->exit_fn();
+
+	test_debugfs_cleanup(td);
+
+	kfree(td);
+}
+
+static struct elevator_type elevator_test_iosched = {
+	.ops = {
+		.elevator_merge_req_fn = test_merged_requests,
+		.elevator_dispatch_fn = test_dispatch_requests,
+		.elevator_add_req_fn = test_add_request,
+		.elevator_former_req_fn = test_former_request,
+		.elevator_latter_req_fn = test_latter_request,
+		.elevator_init_fn = test_init_queue,
+		.elevator_exit_fn = test_exit_queue,
+	},
+	.elevator_name = "test-iosched",
+	.elevator_owner = THIS_MODULE,
+};
+
+static int __init test_init(void)
+{
+	elv_register(&elevator_test_iosched);
+
+	return 0;
+}
+
+static void __exit test_exit(void)
+{
+	elv_unregister(&elevator_test_iosched);
+}
+
+module_init(test_init);
+module_exit(test_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Test IO scheduler");
diff --git a/include/linux/test-iosched.h b/include/linux/test-iosched.h
new file mode 100644
index 0000000..c2db5a9
--- /dev/null
+++ b/include/linux/test-iosched.h
@@ -0,0 +1,218 @@
+#ifndef _LINUX_TEST_IOSCHED_H
+#define _LINUX_TEST_IOSCHED_H
+
+/*
+ * Patterns definitions for read/write requests data
+ */
+#define TEST_PATTERN_SEQUENTIAL	-1
+#define TEST_PATTERN_5A		0x5A5A5A5A
+#define TEST_PATTERN_FF		0xFFFFFFFF
+#define TEST_NO_PATTERN		0xDEADBEEF
+#define BIO_U32_SIZE 1024
+
+struct test_data;
+
+typedef int (prepare_test_fn) (struct test_data *);
+typedef int (run_test_fn) (struct test_data *);
+typedef int (check_test_result_fn) (struct test_data *);
+typedef int (post_test_fn) (struct test_data *);
+typedef char* (get_test_case_str_fn) (struct test_data *);
+typedef void (blk_dev_test_init_fn) (void);
+typedef void (blk_dev_test_exit_fn) (void);
+
+/**
+ * enum test_state - defines the state of the test
+ */
+enum test_state {
+	TEST_IDLE,
+	TEST_RUNNING,
+	TEST_COMPLETED,
+};
+
+/**
+ * enum test_results - defines the success orfailure of the test
+ */
+enum test_results {
+	TEST_NO_RESULT,
+	TEST_FAILED,
+	TEST_PASSED,
+	TEST_NOT_SUPPORTED,
+};
+
+/**
+ * enum req_unique_type - defines a unique request type
+ */
+enum req_unique_type {
+	REQ_UNIQUE_NONE,
+	REQ_UNIQUE_DISCARD,
+	REQ_UNIQUE_FLUSH,
+};
+
+/**
+ * struct test_debug - debugfs directories
+ * @debug_root:		The test-iosched debugfs root directory
+ * @debug_utils_root:	test-iosched debugfs utils root
+ *			directory
+ * @debug_tests_root:	test-iosched debugfs tests root
+ *			directory
+ * @debug_test_result:	Exposes the test result to the user
+ *			space
+ * @start_sector:	The start sector for read/write requests
+ */
+struct test_debug {
+	struct dentry *debug_root;
+	struct dentry *debug_utils_root;
+	struct dentry *debug_tests_root;
+	struct dentry *debug_test_result;
+	struct dentry *start_sector;
+};
+
+/**
+ * struct test_request - defines a test request
+ * @queuelist:		The test requests list
+ * @bios_buffer:	Write/read requests data buffer
+ * @buf_size:		Write/read requests data buffer size (in
+ *			bytes)
+ * @rq:			A block request, to be dispatched
+ * @req_completed:	A flag to indicate if the request was
+ *			completed
+ * @req_result:		Keeps the error code received in the
+ *			request completion callback
+ * @is_err_expected:	A flag to indicate if the request should
+ *			fail
+ * @wr_rd_data_pattern:	A pattern written to the write data
+ *			buffer. Can be used in read requests to
+ *			verify the data
+ * @req_id:		A unique ID to identify a test request
+ *			to ease the debugging of the test cases
+ */
+struct test_request {
+	struct list_head queuelist;
+	unsigned int *bios_buffer;
+	int buf_size;
+	struct request *rq;
+	bool req_completed;
+	int req_result;
+	int is_err_expected;
+	int wr_rd_data_pattern;
+	int req_id;
+};
+
+/**
+ * struct test_info - specific test information
+ * @testcase:		The current running test case
+ * @timeout_msec:	Test specific test timeout
+ * @buf_size:		Write/read requests data buffer size (in
+ *			bytes)
+ * @ignore_run_due_to_fs_wr_reqs: A flag to indicate if the test
+ *			should be re-run in case we get FS write
+ *			requests in theh middle of the test. The
+ *			write requests can be followed by a
+ *			FLUSH request that might cause
+ *			unexpected results of the test.
+ * @prepare_test_fn:	Test specific test preparation callback
+ * @run_test_fn:	Test specific test running callback
+ * @check_test_result_fn: Test specific test result checking
+ *			callback
+ * @get_test_case_str_fn: Test specific function to get the test name
+ * @data:		Test specific private data
+ */
+struct test_info {
+	int testcase;
+	unsigned timeout_msec;
+	bool ignore_run_due_to_fs_wr_reqs;
+	prepare_test_fn *prepare_test_fn;
+	run_test_fn *run_test_fn;
+	check_test_result_fn *check_test_result_fn;
+	post_test_fn *post_test_fn;
+	get_test_case_str_fn *get_test_case_str_fn;
+	void *data;
+};
+
+/**
+ * struct blk_dev_test_type - identifies block device test
+ * @list:	list head pointer
+ * @init_fn:	block device test init callback
+ * @exit_fn:	block device test exit callback
+ */
+struct blk_dev_test_type {
+	struct list_head list;
+	blk_dev_test_init_fn *init_fn;
+	blk_dev_test_exit_fn *exit_fn;
+};
+
+/**
+ * struct test_data - global test iosched data
+ * @queue:		The test IO scheduler requests list
+ * @test_queue:		The test requests list
+ * @next_req:		Points to the next request to be
+ *			dispatched from the test requests list
+ * @wait_q:		A wait queue for waiting for the test
+ *			requests completion
+ * @test_state:		Indicates if there is a running test.
+ *			Used for dispatch function
+ * @test_result:	Indicates if the test passed or failed
+ * @debug:		The test debugfs entries
+ * @req_q:		The block layer request queue
+ * @num_of_write_bios:	The number of write BIOs added to the test requests.
+ *			Used to calcualte the sector number of
+ *			new BIOs.
+ * @start_sector:	The address of the first sector that can
+ *			be accessed by the test
+ * @timeout_timer:	A timer to verify test completion in
+ *			case of non-completed requests
+ * @wr_rd_next_req_id:	A unique ID to identify WRITE/READ
+ *			request to ease the debugging of the
+ *			test cases
+ * @unique_next_req_id:	A unique ID to identify
+ *			FLUSH/DISCARD/SANITIZE request to ease
+ *			the debugging of the test cases
+ * @lock:		A lock to verify running a single test
+ *			at a time
+ * @test_info:		A specific test data to be set by the
+ *			test invokation function
+ * @ignore_round:	A boolean variable indicating that a
+ *			test round was disturbed by an external
+ *			flush request, therefore disqualifying
+ *			the results
+ */
+struct test_data {
+	struct list_head queue;
+	struct list_head test_queue;
+	struct test_request *next_req;
+	wait_queue_head_t wait_q;
+	enum test_state test_state;
+	enum test_results test_result;
+	struct test_debug debug;
+	struct request_queue *req_q;
+	int num_of_write_bios;
+	u32 start_sector;
+	struct timer_list timeout_timer;
+	int wr_rd_next_req_id;
+	int unique_next_req_id;
+	spinlock_t lock;
+	struct test_info test_info;
+	int ignore_round;
+};
+
+extern int test_iosched_start_test(struct test_info *t_info);
+extern void test_iosched_mark_test_completion(void);
+extern int test_iosched_add_unique_test_req(int is_err_expcted,
+		enum req_unique_type req_unique,
+		int start_sec, int nr_sects, rq_end_io_fn *end_req_io);
+extern int test_iosched_add_wr_rd_test_req(int is_err_expcted,
+	      int direction, int start_sec,
+	      int num_bios, int pattern, rq_end_io_fn *end_req_io);
+
+extern struct dentry *test_iosched_get_debugfs_tests_root(void);
+extern struct dentry *test_iosched_get_debugfs_utils_root(void);
+
+extern struct request_queue *test_iosched_get_req_queue(void);
+
+extern void test_iosched_set_test_result(int);
+
+void test_iosched_register(struct blk_dev_test_type *bdt);
+
+void test_iosched_unregister(struct blk_dev_test_type *bdt);
+
+#endif /* _LINUX_TEST_IOSCHED_H */
-- 
1.7.3.3
-- 
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

[PATCH v4 1/1] block: Add test-iosched scheduler

[Maya Erez]

The test scheduler allows testing a block device by dispatching
specific requests according to the test case and declare PASS/FAIL
according to the requests completion error code

Signed-off-by: Maya Erez <merez@codeaurora.org>

diff --git a/Documentation/block/test-iosched.txt b/Documentation/block/test-iosched.txt
new file mode 100644
index 0000000..75d8134
--- /dev/null
+++ b/Documentation/block/test-iosched.txt
@@ -0,0 +1,39 @@
+Test IO scheduler
+==================
+
+The test scheduler allows testing a block device by dispatching
+specific requests according to the test case and declare PASS/FAIL
+according to the requests completion error code.
+
+The test IO scheduler implements the no-op scheduler operations, and uses
+them in order to dispatch the non-test requests when no test is running.
+This will allow to keep a normal FS operation in parallel to the test
+capability.
+The test IO scheduler keeps two different queues, one for real-world requests
+(inserted by the FS) and the other for the test requests.
+The test IO scheduler chooses the queue for dispatch requests according to the
+test state (IDLE/RUNNING).
+
+the test IO scheduler is compiled by default as a dynamic module and enabled
+only if CONFIG_DEBUG_FS is defined.
+
+Each block device test utility that would like to use the test-iosched test
+services, should register as a blk_dev_test_type and supply an init and exit
+callbacks. Those callback are called upon selection (or removal) of the
+test-iosched as the active scheduler. From that point the block device test
+can start a test and supply its own callbacks for preparing, running, result
+checking and cleanup of the test.
+
+Each test is exposed via debugfs and can be triggered by writing to
+the debugfs file. In order to add a new test one should expose a new debugfs
+file for the new test.
+
+Selecting IO schedulers
+-----------------------
+Refer to Documentation/block/switching-sched.txt for information on
+selecting an io scheduler on a per-device basis.
+
+
+May 10 2012, maya Erez <merez@codeaurora.org>
+
+
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 421bef9..af3d6a3 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -12,6 +12,17 @@ config IOSCHED_NOOP
 	  that do their own scheduling and require only minimal assistance from
 	  the kernel.
 
+config IOSCHED_TEST
+	tristate "Test I/O scheduler"
+	depends on DEBUG_FS
+	default m
+	---help---
+	  The test I/O scheduler is a duplicate of the noop scheduler with
+	  addition of test utlity.
+	  It allows testing a block device by dispatching specific requests
+	  according to the test case and declare PASS/FAIL according to the
+	  requests completion error code.
+
 config IOSCHED_DEADLINE
 	tristate "Deadline I/O scheduler"
 	default y
diff --git a/block/Makefile b/block/Makefile
index 39b76ba..436b220 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_BLK_DEV_THROTTLING)	+= blk-throttle.o
 obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o
 obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
 obj-$(CONFIG_IOSCHED_CFQ)	+= cfq-iosched.o
+obj-$(CONFIG_IOSCHED_TEST)	+= test-iosched.o
 
 obj-$(CONFIG_BLOCK_COMPAT)	+= compat_ioctl.o
 obj-$(CONFIG_BLK_DEV_INTEGRITY)	+= blk-integrity.o
diff --git a/block/blk-core.c b/block/blk-core.c
index 5639a3d..54ea4da 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1072,8 +1072,6 @@ struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
 {
 	struct request *rq;
 
-	BUG_ON(rw != READ && rw != WRITE);
-
 	spin_lock_irq(q->queue_lock);
 	if (gfp_mask & __GFP_WAIT)
 		rq = get_request_wait(q, rw, NULL);
@@ -1406,6 +1404,7 @@ void init_request_from_bio(struct request *req, struct bio *bio)
 	req->ioprio = bio_prio(bio);
 	blk_rq_bio_prep(req->q, req, bio);
 }
+EXPORT_SYMBOL(init_request_from_bio);
 
 void blk_queue_bio(struct request_queue *q, struct bio *bio)
 {
diff --git a/block/test-iosched.c b/block/test-iosched.c
new file mode 100644
index 0000000..e4b89d2
--- /dev/null
+++ b/block/test-iosched.c
@@ -0,0 +1,1015 @@
+
+/* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * The test scheduler allows to test the block device by dispatching
+ * specific requests according to the test case and declare PASS/FAIL
+ * according to the requests completion error code.
+ * Each test is exposed via debugfs and can be triggered by writing to
+ * the debugfs file.
+ *
+ */
+
+/* elevator test iosched */
+#include <linux/blkdev.h>
+#include <linux/elevator.h>
+#include <linux/bio.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <linux/test-iosched.h>
+#include <linux/delay.h>
+#include "blk.h"
+
+#define MODULE_NAME "test-iosched"
+#define WR_RD_START_REQ_ID 1234
+#define UNIQUE_START_REQ_ID 5678
+#define TIMEOUT_TIMER_MS 40000
+#define TEST_MAX_TESTCASE_ROUNDS 15
+
+#define test_pr_debug(fmt, args...) pr_debug("%s: "fmt"\n", MODULE_NAME, args)
+#define test_pr_info(fmt, args...) pr_info("%s: "fmt"\n", MODULE_NAME, args)
+#define test_pr_err(fmt, args...) pr_err("%s: "fmt"\n", MODULE_NAME, args)
+
+static DEFINE_SPINLOCK(blk_dev_test_list_lock);
+static LIST_HEAD(blk_dev_test_list);
+static struct test_data *ptd;
+
+/* Get the request after `test_rq' in the test requests list */
+static struct test_request *
+latter_test_request(struct request_queue *q,
+				 struct test_request *test_rq)
+{
+	struct test_data *td = q->elevator->elevator_data;
+
+	if (test_rq->queuelist.next == &td->test_queue)
+		return NULL;
+	return list_entry(test_rq->queuelist.next, struct test_request,
+			  queuelist);
+}
+
+/**
+ * test_iosched_get_req_queue() - returns the request queue
+ * served by the scheduler
+ */
+struct request_queue *test_iosched_get_req_queue(void)
+{
+	if (!ptd)
+		return NULL;
+
+	return ptd->req_q;
+}
+EXPORT_SYMBOL(test_iosched_get_req_queue);
+
+/**
+ * test_iosched_mark_test_completion() - Wakeup the debugfs
+ * thread, waiting on the test completion
+ */
+void test_iosched_mark_test_completion(void)
+{
+	if (!ptd)
+		return;
+
+	ptd->test_state = TEST_COMPLETED;
+	wake_up(&ptd->wait_q);
+}
+EXPORT_SYMBOL(test_iosched_mark_test_completion);
+
+/* Check if all the queued test requests were completed */
+static void check_test_completion(void)
+{
+	struct test_request *test_rq;
+	struct request *rq;
+
+	list_for_each_entry(test_rq, &ptd->test_queue, queuelist) {
+		rq = test_rq->rq;
+		if (!test_rq->req_completed)
+			return;
+	}
+
+	test_pr_info("%s: Test is completed", __func__);
+
+	test_iosched_mark_test_completion();
+}
+
+/*
+ * A callback to be called per bio completion.
+ * Frees the bio memory.
+ */
+static void end_test_bio(struct bio *bio, int err)
+{
+	if (err)
+		clear_bit(BIO_UPTODATE, &bio->bi_flags);
+
+	bio_put(bio);
+}
+
+/*
+ * A callback to be called per request completion.
+ * the request memory is not freed here, will be freed later after the test
+ * results checking.
+ */
+static void end_test_req(struct request *rq, int err)
+{
+	struct test_request *test_rq;
+
+	test_rq = (struct test_request *)rq->elv.priv[0];
+	BUG_ON(!test_rq);
+
+	test_pr_info("%s: request %d completed, err=%d",
+	       __func__, test_rq->req_id, err);
+
+	test_rq->req_completed = 1;
+	test_rq->req_result = err;
+
+	check_test_completion();
+}
+
+/**
+ * test_iosched_add_unique_test_req() - Create and queue a non
+ * read/write request (such as FLUSH/DISCRAD/SANITIZE).
+ * @is_err_expcted:	A flag to indicate if this request
+ *			should succeed or not
+ * @req_unique:		The type of request to add
+ * @start_sec:		start address of the first bio
+ * @nr_sects:		number of sectors in the request
+ * @end_req_io:		specific completion callback. When not
+ *			set, the defaulcallback will be used
+ */
+int test_iosched_add_unique_test_req(int is_err_expcted,
+			enum req_unique_type req_unique,
+			int start_sec, int nr_sects, rq_end_io_fn *end_req_io)
+{
+	struct bio *bio;
+	struct request *rq;
+	int rw_flags;
+	struct test_request *test_rq;
+
+	if (!ptd)
+		return -ENODEV;
+
+	bio = bio_alloc(GFP_KERNEL, 0);
+	if (!bio) {
+		test_pr_err("%s: Failed to allocate a bio", __func__);
+		return -ENODEV;
+	}
+	bio_get(bio);
+	bio->bi_end_io = end_test_bio;
+
+	switch (req_unique) {
+	case REQ_UNIQUE_FLUSH:
+		bio->bi_rw = WRITE_FLUSH;
+		break;
+	case REQ_UNIQUE_DISCARD:
+		bio->bi_rw = REQ_WRITE | REQ_DISCARD;
+		bio->bi_size = nr_sects << 9;
+		bio->bi_sector = start_sec;
+		break;
+	default:
+		test_pr_err("%s: Invalid request type %d", __func__,
+			    req_unique);
+		bio_put(bio);
+		return -ENODEV;
+	}
+
+	rw_flags = bio_data_dir(bio);
+	if (bio->bi_rw & REQ_SYNC)
+		rw_flags |= REQ_SYNC;
+
+	rq = blk_get_request(ptd->req_q, rw_flags, GFP_KERNEL);
+	if (!rq) {
+		test_pr_err("%s: Failed to allocate a request", __func__);
+		bio_put(bio);
+		return -ENODEV;
+	}
+
+	init_request_from_bio(rq, bio);
+	if (end_req_io)
+		rq->end_io = end_req_io;
+	else
+		rq->end_io = end_test_req;
+
+	test_rq = kzalloc(sizeof(struct test_request), GFP_KERNEL);
+	if (!test_rq) {
+		test_pr_err("%s: Failed to allocate a test request", __func__);
+		bio_put(bio);
+		blk_put_request(rq);
+		return -ENODEV;
+	}
+	test_rq->req_completed = 0;
+	test_rq->req_result = -1;
+	test_rq->rq = rq;
+	test_rq->is_err_expected = is_err_expcted;
+	rq->elv.priv[0] = (void *)test_rq;
+	test_rq->req_id = ptd->unique_next_req_id++;
+
+	test_pr_debug(
+		"%s: added request %d to the test requests list, type = %d",
+		__func__, test_rq->req_id, req_unique);
+
+	list_add_tail(&test_rq->queuelist, &ptd->test_queue);
+
+	return 0;
+}
+EXPORT_SYMBOL(test_iosched_add_unique_test_req);
+
+/*
+ * Get a pattern to be filled in the request data buffer.
+ * If the pattern used is (-1) the buffer will be filled with sequential
+ * numbers
+ */
+static void fill_buf_with_pattern(int *buf, int num_bytes, int pattern)
+{
+	int i = 0;
+	int num_of_dwords = num_bytes/sizeof(int);
+
+	if (pattern == TEST_NO_PATTERN)
+		return;
+
+	/* num_bytes should be aligned to sizeof(int) */
+	BUG_ON((num_bytes % sizeof(int)) != 0);
+
+	if (pattern == TEST_PATTERN_SEQUENTIAL) {
+		for (i = 0; i < num_of_dwords; i++)
+			buf[i] = i;
+	} else {
+		for (i = 0; i < num_of_dwords; i++)
+			buf[i] = pattern;
+	}
+}
+
+/**
+ * test_iosched_add_wr_rd_test_req() - Create and queue a
+ * read/write request.
+ * @is_err_expcted:	A flag to indicate if this request
+ *			should succeed or not
+ * @direction:		READ/WRITE
+ * @start_sec:		start address of the first bio
+ * @num_bios:		number of BIOs to be allocated for the
+ *			request
+ * @pattern:		A pattern, to be written into the write
+ *			requests data buffer. In case of READ
+ *			request, the given pattern is kept as
+ *			the expected pattern. The expected
+ *			pattern will be compared in the test
+ *			check result function. If no comparisson
+ *			is required, set pattern to
+ *			TEST_NO_PATTERN.
+ * @end_req_io:		specific completion callback. When not
+ *			set,the default callback will be used
+ *
+ * This function allocates the test request and the block
+ * request and calls blk_rq_map_kern which allocates the
+ * required BIO. The allocated test request and the block
+ * request memory is freed at the end of the test and the
+ * allocated BIO memory is freed by end_test_bio.
+ */
+int test_iosched_add_wr_rd_test_req(int is_err_expcted,
+		      int direction, int start_sec,
+		      int num_bios, int pattern, rq_end_io_fn *end_req_io)
+{
+	struct request *rq = NULL;
+	struct test_request *test_rq = NULL;
+	int rw_flags = 0;
+	int buf_size = 0;
+	int ret = 0, i = 0;
+	unsigned int *bio_ptr = NULL;
+	struct bio *bio = NULL;
+
+	if (!ptd)
+		return -ENODEV;
+
+	rw_flags = direction;
+
+	rq = blk_get_request(ptd->req_q, rw_flags, GFP_KERNEL);
+	if (!rq) {
+		test_pr_err("%s: Failed to allocate a request", __func__);
+		return -ENODEV;
+	}
+
+	test_rq = kzalloc(sizeof(struct test_request), GFP_KERNEL);
+	if (!test_rq) {
+		test_pr_err("%s: Failed to allocate test request", __func__);
+		blk_put_request(rq);
+		return -ENODEV;
+	}
+
+	buf_size = sizeof(unsigned int) * BIO_U32_SIZE * num_bios;
+	test_rq->bios_buffer = kzalloc(buf_size, GFP_KERNEL);
+	if (!test_rq->bios_buffer) {
+		test_pr_err("%s: Failed to allocate the data buf", __func__);
+		goto err;
+	}
+	test_rq->buf_size = buf_size;
+
+	if (direction == WRITE)
+		fill_buf_with_pattern(test_rq->bios_buffer,
+						   buf_size, pattern);
+	test_rq->wr_rd_data_pattern = pattern;
+
+	bio_ptr = test_rq->bios_buffer;
+	for (i = 0; i < num_bios; ++i) {
+		ret = blk_rq_map_kern(ptd->req_q, rq,
+				      (void *)bio_ptr,
+				      sizeof(unsigned int)*BIO_U32_SIZE,
+				      GFP_KERNEL);
+		if (ret) {
+			test_pr_err("%s: blk_rq_map_kern returned error %d",
+				    __func__, ret);
+			goto err;
+		}
+		bio_ptr += BIO_U32_SIZE;
+	}
+
+	if (end_req_io)
+		rq->end_io = end_req_io;
+	else
+		rq->end_io = end_test_req;
+	rq->__sector = start_sec;
+	rq->cmd_type |= REQ_TYPE_FS;
+
+	if (rq->bio) {
+		rq->bio->bi_sector = start_sec;
+		rq->bio->bi_end_io = end_test_bio;
+		bio = rq->bio;
+		while ((bio = bio->bi_next) != NULL)
+			bio->bi_end_io = end_test_bio;
+	}
+
+	ptd->num_of_write_bios += num_bios;
+	test_rq->req_id = ptd->wr_rd_next_req_id++;
+
+	test_rq->req_completed = 0;
+	test_rq->req_result = -1;
+	test_rq->rq = rq;
+	test_rq->is_err_expected = is_err_expcted;
+	rq->elv.priv[0] = (void *)test_rq;
+
+	test_pr_debug(
+		"%s: added request %d to the test requests list, buf_size=%d",
+		__func__, test_rq->req_id, buf_size);
+
+	list_add_tail(&test_rq->queuelist, &ptd->test_queue);
+
+	return 0;
+err:
+	blk_put_request(rq);
+	kfree(test_rq->bios_buffer);
+	return -ENODEV;
+}
+EXPORT_SYMBOL(test_iosched_add_wr_rd_test_req);
+
+/* Converts the testcase number into a string */
+static char *get_test_case_str(struct test_data *td)
+{
+	if (td->test_info.get_test_case_str_fn)
+		return td->test_info.get_test_case_str_fn(td);
+
+	return "Unknown testcase";
+}
+
+/*
+ * Verify that the test request data buffer includes the expected
+ * pattern
+ */
+static int compare_buffer_to_pattern(struct test_request *test_rq)
+{
+	int i = 0;
+	int num_of_dwords = test_rq->buf_size/sizeof(int);
+
+	/* num_bytes should be aligned to sizeof(int) */
+	BUG_ON((test_rq->buf_size % sizeof(int)) != 0);
+	BUG_ON(test_rq->bios_buffer == NULL);
+
+	if (test_rq->wr_rd_data_pattern == TEST_NO_PATTERN)
+		return 0;
+
+	if (test_rq->wr_rd_data_pattern == TEST_PATTERN_SEQUENTIAL) {
+		for (i = 0; i < num_of_dwords; i++) {
+			if (test_rq->bios_buffer[i] != i) {
+				test_pr_err(
+					"%s: wrong pattern 0x%x in index %d",
+					__func__, test_rq->bios_buffer[i], i);
+				return -EINVAL;
+			}
+		}
+	} else {
+		for (i = 0; i < num_of_dwords; i++) {
+			if (test_rq->bios_buffer[i] !=
+			    test_rq->wr_rd_data_pattern) {
+				test_pr_err(
+					"%s: wrong pattern 0x%x in index %d",
+					__func__, test_rq->bios_buffer[i], i);
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Determine if the test passed or failed.
+ * The function checks the test request completion value and calls
+ * check_testcase_result for result checking that are specific
+ * to a test case.
+ */
+static int check_test_result(struct test_data *td)
+{
+	struct test_request *test_rq;
+	struct request *rq;
+	int res = 0;
+	static int run;
+
+	list_for_each_entry(test_rq, &ptd->test_queue, queuelist) {
+		rq = test_rq->rq;
+		if (!test_rq->req_completed) {
+			test_pr_err("%s: rq %d not completed", __func__,
+				    test_rq->req_id);
+			res = -EINVAL;
+			goto err;
+		}
+
+		if ((test_rq->req_result < 0) && !test_rq->is_err_expected) {
+			test_pr_err(
+				"%s: rq %d completed with err, not as expected",
+				__func__, test_rq->req_id);
+			res = -EINVAL;
+			goto err;
+		}
+		if ((test_rq->req_result == 0) && test_rq->is_err_expected) {
+			test_pr_err("%s: rq %d succeeded, not as expected",
+				    __func__, test_rq->req_id);
+			res = -EINVAL;
+			goto err;
+		}
+		if (rq_data_dir(test_rq->rq) == READ) {
+			res = compare_buffer_to_pattern(test_rq);
+			if (res) {
+				test_pr_err("%s: read pattern not as expected",
+					    __func__);
+				res = -EINVAL;
+				goto err;
+			}
+		}
+	}
+
+	if (td->test_info.check_test_result_fn) {
+		res = td->test_info.check_test_result_fn(td);
+		if (res)
+			goto err;
+	}
+
+	test_pr_info("%s: %s, run# %03d, PASSED",
+			    __func__, get_test_case_str(td), ++run);
+	td->test_result = TEST_PASSED;
+
+	return 0;
+err:
+	test_pr_err("%s: %s, run# %03d, FAILED",
+		    __func__, get_test_case_str(td), ++run);
+	td->test_result = TEST_FAILED;
+	return res;
+}
+
+/* Create and queue the required requests according to the test case */
+static int prepare_test(struct test_data *td)
+{
+	int ret = 0;
+
+	if (td->test_info.prepare_test_fn) {
+		ret = td->test_info.prepare_test_fn(td);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* Run the test */
+static int run_test(struct test_data *td)
+{
+	int ret = 0;
+
+	if (td->test_info.run_test_fn) {
+		ret = td->test_info.run_test_fn(td);
+		return ret;
+	}
+
+	/*
+	 * Set the next_req pointer to the first request in the test requests
+	 * list
+	 */
+	if (!list_empty(&td->test_queue))
+		td->next_req = list_entry(td->test_queue.next,
+					  struct test_request, queuelist);
+	__blk_run_queue(td->req_q);
+
+	return 0;
+}
+
+/* Free the allocated test requests, their requests and BIOs buffer */
+static void free_test_requests(struct test_data *td)
+{
+	struct test_request *test_rq;
+	while (!list_empty(&td->test_queue)) {
+		test_rq = list_entry(td->test_queue.next, struct test_request,
+				     queuelist);
+		list_del_init(&test_rq->queuelist);
+		blk_put_request(test_rq->rq);
+		kfree(test_rq->bios_buffer);
+		kfree(test_rq);
+	}
+}
+
+/*
+ * Do post test operations.
+ * Free the allocated test requests, their requests and BIOs buffer.
+ */
+static int post_test(struct test_data *td)
+{
+	int ret = 0;
+
+	if (td->test_info.post_test_fn)
+		ret = td->test_info.post_test_fn(td);
+
+	ptd->test_info.testcase = 0;
+	ptd->test_state = TEST_IDLE;
+
+	free_test_requests(td);
+
+	return ret;
+}
+
+/*
+ * The timer verifies that the test will be completed even if we don't get
+ * the completion callback for all the requests.
+ */
+static void test_timeout_handler(unsigned long data)
+{
+	struct test_data *td = (struct test_data *)data;
+
+	test_pr_info("%s: TIMEOUT timer expired", __func__);
+	td->test_state = TEST_COMPLETED;
+	wake_up(&td->wait_q);
+	return;
+}
+
+static unsigned int get_timeout_msec(struct test_data *td)
+{
+	if (td->test_info.timeout_msec)
+		return td->test_info.timeout_msec;
+	else
+		return TIMEOUT_TIMER_MS;
+}
+
+/**
+ * test_iosched_start_test() - Prepares and runs the test.
+ * @t_info:	the current test testcase and callbacks
+ *		functions
+ *
+ * The function also checks the test result upon test completion
+ */
+int test_iosched_start_test(struct test_info *t_info)
+{
+	int ret = 0;
+	unsigned timeout_msec;
+	int counter = 0;
+	char *test_name = NULL;
+
+	if (!ptd)
+		return -ENODEV;
+
+	if (!t_info) {
+		ptd->test_result = TEST_FAILED;
+		return -EINVAL;
+	}
+
+	do {
+		if (ptd->ignore_round)
+			/*
+			 * We ignored the last run due to FS write requests.
+			 * Sleep to allow those requests to be issued
+			 */
+			msleep(2000);
+
+		spin_lock(&ptd->lock);
+
+		if (ptd->test_state != TEST_IDLE) {
+			test_pr_info(
+				"%s: Another test is running, try again later",
+				__func__);
+			return -EINVAL;
+		}
+
+		if (ptd->start_sector == 0) {
+			test_pr_err("%s: Invalid start sector\n. "
+				"User should set the start sector before "
+				"running the test using this command:\n"
+				"echo <START_SECTOR> > "
+				"/<path-to-debugfs>/test-iosched/start_sector",
+			       __func__);
+			ptd->test_result = TEST_FAILED;
+			spin_unlock(&ptd->lock);
+			return -EINVAL;
+		}
+
+		memcpy(&ptd->test_info, t_info, sizeof(struct test_info));
+
+		ptd->next_req = NULL;
+		ptd->test_result = TEST_NO_RESULT;
+		ptd->num_of_write_bios = 0;
+
+		ptd->unique_next_req_id = UNIQUE_START_REQ_ID;
+		ptd->wr_rd_next_req_id = WR_RD_START_REQ_ID;
+
+		ptd->test_state = TEST_RUNNING;
+
+		spin_unlock(&ptd->lock);
+
+		timeout_msec = get_timeout_msec(ptd);
+		mod_timer(&ptd->timeout_timer, jiffies +
+			  msecs_to_jiffies(timeout_msec));
+
+		if (ptd->test_info.get_test_case_str_fn)
+			test_name = ptd->test_info.get_test_case_str_fn(ptd);
+		else
+			test_name = "Unknown testcase";
+		test_pr_info("%s: Starting test %s\n", __func__, test_name);
+
+		ret = prepare_test(ptd);
+		if (ret) {
+			test_pr_err("%s: failed to prepare the test\n",
+				    __func__);
+			goto error;
+		}
+
+		ret = run_test(ptd);
+		if (ret) {
+			test_pr_err("%s: failed to run the test\n", __func__);
+			goto error;
+		}
+
+		test_pr_info("%s: Waiting for the test completion", __func__);
+
+		wait_event(ptd->wait_q, ptd->test_state == TEST_COMPLETED);
+		del_timer_sync(&ptd->timeout_timer);
+
+		if (!ptd->ignore_round) {
+			ret = check_test_result(ptd);
+			if (ret) {
+				test_pr_err("%s: check_test_result failed\n",
+					    __func__);
+				goto error;
+			}
+		} else {
+			test_pr_info(
+			"%s: Round canceled (Got wr reqs in the middle)",
+			__func__);
+		}
+
+		ret = post_test(ptd);
+		if (ret) {
+			test_pr_err("%s: post_test failed\n", __func__);
+			goto error;
+		}
+
+		/*
+		 * Wakeup the queue thread to fetch FS requests that might got
+		 * postponded due to the test
+		 */
+		__blk_run_queue(ptd->req_q);
+
+		if (counter == TEST_MAX_TESTCASE_ROUNDS) {
+			test_pr_info("%s: Too many rounds did not succeed...",
+			     __func__);
+			ptd->test_result = TEST_FAILED;
+		}
+
+	} while ((ptd->ignore_round) && (counter < TEST_MAX_TESTCASE_ROUNDS));
+
+	if (ptd->test_result == TEST_PASSED)
+		return 0;
+	else
+		return -EINVAL;
+
+error:
+	ptd->test_result = TEST_FAILED;
+	ptd->test_info.testcase = 0;
+	post_test(ptd);
+	return ret;
+}
+EXPORT_SYMBOL(test_iosched_start_test);
+
+/**
+ * test_iosched_register() - register a block device test
+ * utility.
+ * @bdt:	the block device test type to register
+ */
+void test_iosched_register(struct blk_dev_test_type *bdt)
+{
+	spin_lock(&blk_dev_test_list_lock);
+	list_add_tail(&bdt->list, &blk_dev_test_list);
+	spin_unlock(&blk_dev_test_list_lock);
+}
+EXPORT_SYMBOL_GPL(test_iosched_register);
+
+/**
+ * test_iosched_unregister() - unregister a block device test
+ * utility.
+ * @bdt:	the block device test type to unregister
+ */
+void test_iosched_unregister(struct blk_dev_test_type *bdt)
+{
+	spin_lock(&blk_dev_test_list_lock);
+	list_del_init(&bdt->list);
+	spin_unlock(&blk_dev_test_list_lock);
+}
+EXPORT_SYMBOL_GPL(test_iosched_unregister);
+
+/**
+ * test_iosched_set_test_result() - Set the test
+ * result(PASS/FAIL)
+ * @test_result:	the test result
+ */
+void test_iosched_set_test_result(int test_result)
+{
+	if (!ptd)
+		return;
+
+	ptd->test_result = test_result;
+}
+EXPORT_SYMBOL(test_iosched_set_test_result);
+
+/**
+ * test_iosched_get_debugfs_tests_root() - returns the root
+ * debugfs directory for the test_iosched tests
+ */
+struct dentry *test_iosched_get_debugfs_tests_root(void)
+{
+	if (!ptd)
+		return NULL;
+
+	return ptd->debug.debug_tests_root;
+}
+EXPORT_SYMBOL(test_iosched_get_debugfs_tests_root);
+
+/**
+ * test_iosched_get_debugfs_utils_root() - returns the root
+ * debugfs directory for the test_iosched utils
+ */
+struct dentry *test_iosched_get_debugfs_utils_root(void)
+{
+	if (!ptd)
+		return NULL;
+
+	return ptd->debug.debug_utils_root;
+}
+EXPORT_SYMBOL(test_iosched_get_debugfs_utils_root);
+
+static int test_debugfs_init(struct test_data *td)
+{
+	td->debug.debug_root = debugfs_create_dir("test-iosched", NULL);
+	if (!td->debug.debug_root)
+		return -ENOENT;
+
+	td->debug.debug_tests_root = debugfs_create_dir("tests",
+							td->debug.debug_root);
+	if (!td->debug.debug_tests_root)
+		goto err;
+
+	td->debug.debug_utils_root = debugfs_create_dir("utils",
+							td->debug.debug_root);
+	if (!td->debug.debug_utils_root)
+		goto err;
+
+	td->debug.debug_test_result = debugfs_create_u32(
+					"test_result",
+					S_IRUGO | S_IWUGO,
+					td->debug.debug_utils_root,
+					&td->test_result);
+	if (!td->debug.debug_test_result)
+		goto err;
+
+	td->debug.start_sector = debugfs_create_u32(
+					"start_sector",
+					S_IRUGO | S_IWUGO,
+					td->debug.debug_utils_root,
+					&td->start_sector);
+	if (!td->debug.start_sector)
+		goto err;
+
+	return 0;
+
+err:
+	debugfs_remove_recursive(td->debug.debug_root);
+	return -ENOENT;
+}
+
+static void test_debugfs_cleanup(struct test_data *td)
+{
+	debugfs_remove_recursive(td->debug.debug_root);
+}
+
+static void print_req(struct request *req)
+{
+	struct bio *bio;
+	struct test_request *test_rq;
+
+	if (!req)
+		return;
+
+	test_rq = (struct test_request *)req->elv.priv[0];
+
+	if (test_rq) {
+		test_pr_debug("%s: Dispatch request %d: "
+			"__data_len=0x%x, __sector=0x%lx, atomic_flags=0x%lx, "
+		       "cmd_flags=0x%x, cmd_len=0x%x, cmd_type=0x%x, "
+		       "nr_phys_segments=%d, num_of_sectors=%d",
+		       __func__, test_rq->req_id, req->__data_len,
+		       (unsigned long)req->__sector,
+		       req->atomic_flags, req->cmd_flags, req->cmd_len,
+		       req->cmd_type,  req->nr_phys_segments,
+		       blk_rq_sectors(req));
+		bio = req->bio;
+		test_pr_debug("%s: bio: bi_size=%d, bi_sector=0x%lx",
+			      __func__, bio->bi_size,
+			      (unsigned long)bio->bi_sector);
+		while ((bio = bio->bi_next) != NULL) {
+			test_pr_debug("%s: bio: bi_size=%d, bi_sector=0x%lx",
+				      __func__, bio->bi_size,
+				      (unsigned long)bio->bi_sector);
+		}
+	}
+}
+
+static void test_merged_requests(struct request_queue *q,
+			 struct request *rq, struct request *next)
+{
+	list_del_init(&next->queuelist);
+}
+
+/*
+ * Dispatch a test request in case there is a running test Otherwise, dispatch
+ * a request that was queued by the FS to keep the card functional.
+ */
+static int test_dispatch_requests(struct request_queue *q, int force)
+{
+	struct test_data *td = q->elevator->elevator_data;
+	struct request *rq = NULL;
+
+	switch (td->test_state) {
+	case TEST_IDLE:
+		if (!list_empty(&td->queue)) {
+			rq = list_entry(td->queue.next, struct request,
+					queuelist);
+			list_del_init(&rq->queuelist);
+			elv_dispatch_sort(q, rq);
+			return 1;
+		}
+		break;
+	case TEST_RUNNING:
+		if (td->next_req) {
+			rq = td->next_req->rq;
+			td->next_req =
+				latter_test_request(td->req_q, td->next_req);
+			if (!rq)
+				return 0;
+			print_req(rq);
+			elv_dispatch_sort(q, rq);
+			return 1;
+		}
+		break;
+	case TEST_COMPLETED:
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+
+static void test_add_request(struct request_queue *q,
+				     struct request *rq)
+{
+	struct test_data *td = q->elevator->elevator_data;
+
+	list_add_tail(&rq->queuelist, &td->queue);
+
+	if (ptd->test_info.ignore_run_due_to_fs_wr_reqs) {
+		if ((rq_data_dir(rq) == WRITE) &&
+		    (td->test_state == TEST_RUNNING)) {
+			test_pr_info(
+				"%s: got WRITE req in the middle of the test",
+				__func__);
+			td->ignore_round = 1;
+		}
+	}
+}
+
+static struct request *
+test_former_request(struct request_queue *q, struct request *rq)
+{
+	struct test_data *td = q->elevator->elevator_data;
+
+	if (rq->queuelist.prev == &td->queue)
+		return NULL;
+	return list_entry(rq->queuelist.prev, struct request, queuelist);
+}
+
+static struct request *
+test_latter_request(struct request_queue *q, struct request *rq)
+{
+	struct test_data *td = q->elevator->elevator_data;
+
+	if (rq->queuelist.next == &td->queue)
+		return NULL;
+	return list_entry(rq->queuelist.next, struct request, queuelist);
+}
+
+static int test_init_queue(struct request_queue *q)
+{
+	struct blk_dev_test_type *__bdt;
+
+	ptd = kmalloc_node(sizeof(struct test_data), GFP_KERNEL,
+			     q->node);
+	if (!ptd) {
+		test_pr_err("%s: failed to allocate test data", __func__);
+		return -ENODEV;
+	}
+	memset((void *)ptd, 0, sizeof(struct test_data));
+	INIT_LIST_HEAD(&ptd->queue);
+	INIT_LIST_HEAD(&ptd->test_queue);
+	init_waitqueue_head(&ptd->wait_q);
+	ptd->req_q = q;
+	q->elevator->elevator_data = ptd;
+
+	setup_timer(&ptd->timeout_timer, test_timeout_handler,
+		    (unsigned long)ptd);
+
+	spin_lock_init(&ptd->lock);
+
+	if (test_debugfs_init(ptd)) {
+		test_pr_err("%s: Failed to create debugfs files", __func__);
+		return -ENODEV;
+	}
+
+	list_for_each_entry(__bdt, &blk_dev_test_list, list)
+		__bdt->init_fn();
+
+	return 0;
+}
+
+static void test_exit_queue(struct elevator_queue *e)
+{
+	struct test_data *td = e->elevator_data;
+	struct blk_dev_test_type *__bdt;
+
+	BUG_ON(!list_empty(&td->queue));
+
+	list_for_each_entry(__bdt, &blk_dev_test_list, list)
+		__bdt->exit_fn();
+
+	test_debugfs_cleanup(td);
+
+	kfree(td);
+}
+
+static struct elevator_type elevator_test_iosched = {
+	.ops = {
+		.elevator_merge_req_fn = test_merged_requests,
+		.elevator_dispatch_fn = test_dispatch_requests,
+		.elevator_add_req_fn = test_add_request,
+		.elevator_former_req_fn = test_former_request,
+		.elevator_latter_req_fn = test_latter_request,
+		.elevator_init_fn = test_init_queue,
+		.elevator_exit_fn = test_exit_queue,
+	},
+	.elevator_name = "test-iosched",
+	.elevator_owner = THIS_MODULE,
+};
+
+static int __init test_init(void)
+{
+	elv_register(&elevator_test_iosched);
+
+	return 0;
+}
+
+static void __exit test_exit(void)
+{
+	elv_unregister(&elevator_test_iosched);
+}
+
+module_init(test_init);
+module_exit(test_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Test IO scheduler");
diff --git a/include/linux/test-iosched.h b/include/linux/test-iosched.h
new file mode 100644
index 0000000..c2db5a9
--- /dev/null
+++ b/include/linux/test-iosched.h
@@ -0,0 +1,218 @@
+#ifndef _LINUX_TEST_IOSCHED_H
+#define _LINUX_TEST_IOSCHED_H
+
+/*
+ * Patterns definitions for read/write requests data
+ */
+#define TEST_PATTERN_SEQUENTIAL	-1
+#define TEST_PATTERN_5A		0x5A5A5A5A
+#define TEST_PATTERN_FF		0xFFFFFFFF
+#define TEST_NO_PATTERN		0xDEADBEEF
+#define BIO_U32_SIZE 1024
+
+struct test_data;
+
+typedef int (prepare_test_fn) (struct test_data *);
+typedef int (run_test_fn) (struct test_data *);
+typedef int (check_test_result_fn) (struct test_data *);
+typedef int (post_test_fn) (struct test_data *);
+typedef char* (get_test_case_str_fn) (struct test_data *);
+typedef void (blk_dev_test_init_fn) (void);
+typedef void (blk_dev_test_exit_fn) (void);
+
+/**
+ * enum test_state - defines the state of the test
+ */
+enum test_state {
+	TEST_IDLE,
+	TEST_RUNNING,
+	TEST_COMPLETED,
+};
+
+/**
+ * enum test_results - defines the success orfailure of the test
+ */
+enum test_results {
+	TEST_NO_RESULT,
+	TEST_FAILED,
+	TEST_PASSED,
+	TEST_NOT_SUPPORTED,
+};
+
+/**
+ * enum req_unique_type - defines a unique request type
+ */
+enum req_unique_type {
+	REQ_UNIQUE_NONE,
+	REQ_UNIQUE_DISCARD,
+	REQ_UNIQUE_FLUSH,
+};
+
+/**
+ * struct test_debug - debugfs directories
+ * @debug_root:		The test-iosched debugfs root directory
+ * @debug_utils_root:	test-iosched debugfs utils root
+ *			directory
+ * @debug_tests_root:	test-iosched debugfs tests root
+ *			directory
+ * @debug_test_result:	Exposes the test result to the user
+ *			space
+ * @start_sector:	The start sector for read/write requests
+ */
+struct test_debug {
+	struct dentry *debug_root;
+	struct dentry *debug_utils_root;
+	struct dentry *debug_tests_root;
+	struct dentry *debug_test_result;
+	struct dentry *start_sector;
+};
+
+/**
+ * struct test_request - defines a test request
+ * @queuelist:		The test requests list
+ * @bios_buffer:	Write/read requests data buffer
+ * @buf_size:		Write/read requests data buffer size (in
+ *			bytes)
+ * @rq:			A block request, to be dispatched
+ * @req_completed:	A flag to indicate if the request was
+ *			completed
+ * @req_result:		Keeps the error code received in the
+ *			request completion callback
+ * @is_err_expected:	A flag to indicate if the request should
+ *			fail
+ * @wr_rd_data_pattern:	A pattern written to the write data
+ *			buffer. Can be used in read requests to
+ *			verify the data
+ * @req_id:		A unique ID to identify a test request
+ *			to ease the debugging of the test cases
+ */
+struct test_request {
+	struct list_head queuelist;
+	unsigned int *bios_buffer;
+	int buf_size;
+	struct request *rq;
+	bool req_completed;
+	int req_result;
+	int is_err_expected;
+	int wr_rd_data_pattern;
+	int req_id;
+};
+
+/**
+ * struct test_info - specific test information
+ * @testcase:		The current running test case
+ * @timeout_msec:	Test specific test timeout
+ * @buf_size:		Write/read requests data buffer size (in
+ *			bytes)
+ * @ignore_run_due_to_fs_wr_reqs: A flag to indicate if the test
+ *			should be re-run in case we get FS write
+ *			requests in theh middle of the test. The
+ *			write requests can be followed by a
+ *			FLUSH request that might cause
+ *			unexpected results of the test.
+ * @prepare_test_fn:	Test specific test preparation callback
+ * @run_test_fn:	Test specific test running callback
+ * @check_test_result_fn: Test specific test result checking
+ *			callback
+ * @get_test_case_str_fn: Test specific function to get the test name
+ * @data:		Test specific private data
+ */
+struct test_info {
+	int testcase;
+	unsigned timeout_msec;
+	bool ignore_run_due_to_fs_wr_reqs;
+	prepare_test_fn *prepare_test_fn;
+	run_test_fn *run_test_fn;
+	check_test_result_fn *check_test_result_fn;
+	post_test_fn *post_test_fn;
+	get_test_case_str_fn *get_test_case_str_fn;
+	void *data;
+};
+
+/**
+ * struct blk_dev_test_type - identifies block device test
+ * @list:	list head pointer
+ * @init_fn:	block device test init callback
+ * @exit_fn:	block device test exit callback
+ */
+struct blk_dev_test_type {
+	struct list_head list;
+	blk_dev_test_init_fn *init_fn;
+	blk_dev_test_exit_fn *exit_fn;
+};
+
+/**
+ * struct test_data - global test iosched data
+ * @queue:		The test IO scheduler requests list
+ * @test_queue:		The test requests list
+ * @next_req:		Points to the next request to be
+ *			dispatched from the test requests list
+ * @wait_q:		A wait queue for waiting for the test
+ *			requests completion
+ * @test_state:		Indicates if there is a running test.
+ *			Used for dispatch function
+ * @test_result:	Indicates if the test passed or failed
+ * @debug:		The test debugfs entries
+ * @req_q:		The block layer request queue
+ * @num_of_write_bios:	The number of write BIOs added to the test requests.
+ *			Used to calcualte the sector number of
+ *			new BIOs.
+ * @start_sector:	The address of the first sector that can
+ *			be accessed by the test
+ * @timeout_timer:	A timer to verify test completion in
+ *			case of non-completed requests
+ * @wr_rd_next_req_id:	A unique ID to identify WRITE/READ
+ *			request to ease the debugging of the
+ *			test cases
+ * @unique_next_req_id:	A unique ID to identify
+ *			FLUSH/DISCARD/SANITIZE request to ease
+ *			the debugging of the test cases
+ * @lock:		A lock to verify running a single test
+ *			at a time
+ * @test_info:		A specific test data to be set by the
+ *			test invokation function
+ * @ignore_round:	A boolean variable indicating that a
+ *			test round was disturbed by an external
+ *			flush request, therefore disqualifying
+ *			the results
+ */
+struct test_data {
+	struct list_head queue;
+	struct list_head test_queue;
+	struct test_request *next_req;
+	wait_queue_head_t wait_q;
+	enum test_state test_state;
+	enum test_results test_result;
+	struct test_debug debug;
+	struct request_queue *req_q;
+	int num_of_write_bios;
+	u32 start_sector;
+	struct timer_list timeout_timer;
+	int wr_rd_next_req_id;
+	int unique_next_req_id;
+	spinlock_t lock;
+	struct test_info test_info;
+	int ignore_round;
+};
+
+extern int test_iosched_start_test(struct test_info *t_info);
+extern void test_iosched_mark_test_completion(void);
+extern int test_iosched_add_unique_test_req(int is_err_expcted,
+		enum req_unique_type req_unique,
+		int start_sec, int nr_sects, rq_end_io_fn *end_req_io);
+extern int test_iosched_add_wr_rd_test_req(int is_err_expcted,
+	      int direction, int start_sec,
+	      int num_bios, int pattern, rq_end_io_fn *end_req_io);
+
+extern struct dentry *test_iosched_get_debugfs_tests_root(void);
+extern struct dentry *test_iosched_get_debugfs_utils_root(void);
+
+extern struct request_queue *test_iosched_get_req_queue(void);
+
+extern void test_iosched_set_test_result(int);
+
+void test_iosched_register(struct blk_dev_test_type *bdt);
+
+void test_iosched_unregister(struct blk_dev_test_type *bdt);
+
+#endif /* _LINUX_TEST_IOSCHED_H */
-- 
1.7.3.3
-- 
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

Re: [PATCH v4 1/1] block: Add test-iosched scheduler

[Jeff Moyer]

Maya Erez <merez@codeaurora.org> writes:

> The test scheduler allows testing a block device by dispatching
> specific requests according to the test case and declare PASS/FAIL
> according to the requests completion error code

What sort of tests have you written that make use of this
infrastructure?

> @@ -1072,8 +1072,6 @@ struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
>  {
>  	struct request *rq;
>  
> -	BUG_ON(rw != READ && rw != WRITE);
> -

Please explain this.

Cheers,
Jeff

Re: [PATCH v4 1/1] block: Add test-iosched scheduler

[Jeff Moyer]

Maya Erez <merez@codeaurora.org> writes:

> The test scheduler allows testing a block device by dispatching
> specific requests according to the test case and declare PASS/FAIL
> according to the requests completion error code

What sort of tests have you written that make use of this
infrastructure?

> @@ -1072,8 +1072,6 @@ struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
>  {
>  	struct request *rq;
>  
> -	BUG_ON(rw != READ && rw != WRITE);
> -

Please explain this.

Cheers,
Jeff

Re: [PATCH v4 1/1] block: Add test-iosched scheduler

[merez]

On Tue, June 12, 2012 7:09 am, Jeff Moyer wrote:
> Maya Erez <merez@codeaurora.org> writes:
>
>> The test scheduler allows testing a block device by dispatching
>> specific requests according to the test case and declare PASS/FAIL
>> according to the requests completion error code
>
> What sort of tests have you written that make use of this
> infrastructure?
>
>> @@ -1072,8 +1072,6 @@ struct request *blk_get_request(struct
>> request_queue *q, int rw, gfp_t gfp_mask)
>>  {
>>  	struct request *rq;
>>
>> -	BUG_ON(rw != READ && rw != WRITE);
>> -
>
> Please explain this.
get_request and get_request_wait, called by blk_get_request, expects to
get the REQ_SYNC flag in addition to the read/write flag. Moreover, it
uses the REQ_SYNC flag in its algorithm decision making.
However blk_get_request expects to get a Boolean to indicate only
read/write flag and cannot handle the REQ_SYNC flag.
>
> Cheers,
> Jeff
>


-- 
Sent by consultant of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

Re: [PATCH v4 1/1] block: Add test-iosched scheduler

[Jeff Moyer]

merez@codeaurora.org writes:

> On Tue, June 12, 2012 7:09 am, Jeff Moyer wrote:
>> Maya Erez <merez@codeaurora.org> writes:
>>
>>> The test scheduler allows testing a block device by dispatching
>>> specific requests according to the test case and declare PASS/FAIL
>>> according to the requests completion error code
>>
>> What sort of tests have you written that make use of this
>> infrastructure?
>>
>>> @@ -1072,8 +1072,6 @@ struct request *blk_get_request(struct
>>> request_queue *q, int rw, gfp_t gfp_mask)
>>>  {
>>>  	struct request *rq;
>>>
>>> -	BUG_ON(rw != READ && rw != WRITE);
>>> -
>>
>> Please explain this.
> get_request and get_request_wait, called by blk_get_request, expects to
> get the REQ_SYNC flag in addition to the read/write flag. Moreover, it
> uses the REQ_SYNC flag in its algorithm decision making.
> However blk_get_request expects to get a Boolean to indicate only
> read/write flag and cannot handle the REQ_SYNC flag.

Right, so why is it okay to change this?  Right now, blk_get_request is
used for block special requests.  There is no sense of sync vs. async
for such requests (that's an fs request notion).  Perhaps you're calling
the wrong function?

Cheers,
Jeff

Re: [PATCH v4 1/1] block: Add test-iosched scheduler

[merez]

On Tue, June 12, 2012 1:13 pm, Jeff Moyer wrote:
> merez@codeaurora.org writes:
>
>> On Tue, June 12, 2012 7:09 am, Jeff Moyer wrote:
>>> Maya Erez <merez@codeaurora.org> writes:
>>>
>>>> The test scheduler allows testing a block device by dispatching
>>>> specific requests according to the test case and declare PASS/FAIL
>>>> according to the requests completion error code
>>>
>>> What sort of tests have you written that make use of this
>>> infrastructure?
>>>
>>>> @@ -1072,8 +1072,6 @@ struct request *blk_get_request(struct
>>>> request_queue *q, int rw, gfp_t gfp_mask)
>>>>  {
>>>>  	struct request *rq;
>>>>
>>>> -	BUG_ON(rw != READ && rw != WRITE);
>>>> -
>>>
>>> Please explain this.
>> get_request and get_request_wait, called by blk_get_request, expects to
>> get the REQ_SYNC flag in addition to the read/write flag. Moreover, it
>> uses the REQ_SYNC flag in its algorithm decision making.
>> However blk_get_request expects to get a Boolean to indicate only
>> read/write flag and cannot handle the REQ_SYNC flag.
>
> Right, so why is it okay to change this?  Right now, blk_get_request is
> used for block special requests.  There is no sense of sync vs. async
> for such requests (that's an fs request notion).  Perhaps you're calling
> the wrong function?
>
> Cheers,
> Jeff
>
I use this function to get a WRITE_FLUSH request (which includes in its
flags the REQ_SYNC flag).
Is there another function I should use for this purpose?

Thanks,
Maya
-- 
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Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum