[PATCH v5 1/3] block: Add test-iosched scheduler

Maya Erez
2012-07-31T14:26:39Z

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>
---
Documentation/block/test-iosched.txt | 39 ++
block/Kconfig.iosched | 11 +
block/Makefile | 1 +
block/blk-core.c | 3 +-
block/test-iosched.c | 1038 ++++++++++++++++++++++++++++++++++
include/linux/test-iosched.h | 233 ++++++++
6 files changed, 1323 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

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 c3b17c3..6fe111e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1085,8 +1085,6 @@ 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);
@@ -1419,6 +1417,7 @@ 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..d3d10d3
--- /dev/null
+++ b/block/test-iosched.c
@@ -0,0 +1,1038 @@
+/* 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 = true;
+ 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 = false;
+ test_rq->req_result = -EINVAL;
+ 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 = false;
+ test_rq->req_result = -EINVAL;
+ 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;
+ struct bio *bio;
+
+ while (!list_empty(&td->test_queue)) {
+ test_rq = list_entry(td->test_queue.next, struct test_request,
+ queuelist);
+ list_del_init(&test_rq->queuelist);
+ /*
+ * If the request was not completed we need to free its BIOs
+ * and remove it from the packed list
+ */
+ if (!test_rq->req_completed) {
+ test_pr_info(
+ "%s: Freeing memory of an uncompleted request",
+ __func__);
+ list_del_init(&test_rq->rq->queuelist);
+ while ((bio = test_rq->rq->bio) != NULL) {
+ test_rq->rq->bio = bio->bi_next;
+ bio_put(bio);
+ }
+ }
+ 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->next_req = NULL;
+
+ free_test_requests(td);
+
+ ptd->test_info.testcase = 0;
+ ptd->test_state = TEST_IDLE;
+
+ 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__);
+ spin_unlock(&ptd->lock);
+ return -EBUSY;
+ }
+
+ if (ptd->start_sector == 0) {
+ test_pr_err("%s: Invalid 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->ignore_round = false;
+ ptd->fs_wr_reqs_during_test = false;
+
+ 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);
+
+ ret = check_test_result(ptd);
+ if (ret) {
+ test_pr_err("%s: check_test_result failed\n",
+ __func__);
+ goto error;
+ }
+
+ 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 (ptd->ignore_round)
+ test_pr_info(
+ "%s: Round canceled (Got wr reqs in the middle)",
+ __func__);
+
+ 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:
+ post_test(ptd);
+ ptd->test_result = TEST_FAILED;
+ 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_set_ignore_round() - Set the ignore_round flag
+ * @ignore_round: A flag to indicate if this test round
+ * should be ignored and re-run
+ */
+void test_iosched_set_ignore_round(bool ignore_round)
+{
+ if (!ptd)
+ return;
+
+ ptd->ignore_round = ignore_round;
+}
+EXPORT_SYMBOL(test_iosched_set_ignore_round);
+
+/**
+ * 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: __sector=0x%lx",
+ __func__, test_rq->req_id, (unsigned long)req->__sector);
+ test_pr_debug("%s: nr_phys_segments=%d, num_of_sectors=%d",
+ __func__, 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);
+
+ /*
+ * The write requests can be followed by a FLUSH request that might
+ * cause unexpected results of the test.
+ */
+ if ((rq_data_dir(rq) == WRITE) && (td->test_state == TEST_RUNNING)) {
+ test_pr_debug("%s: got WRITE req in the middle of the test",
+ __func__);
+ td->fs_wr_reqs_during_test = true;
+ }
+}
+
+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 v2");
+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..8054409
--- /dev/null
+++ b/include/linux/test-iosched.h
@@ -0,0 +1,233 @@
+/* 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.
+ *
+ */
+
+#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)
+ * @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;
+ 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;
+ bool fs_wr_reqs_during_test;
+ bool 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_set_ignore_round(bool ignore_round);
+
+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.