block: add fault injection mechanism for faking request timeouts
Only works for the generic request timer handling. Allows one to
sporadically ignore request completions, thus exercising the timeout
handling.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 6e5c781..9b4ad13 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -4,9 +4,68 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/blkdev.h>
+#include <linux/fault-inject.h>
#include "blk.h"
+#ifdef CONFIG_FAIL_IO_TIMEOUT
+
+static DECLARE_FAULT_ATTR(fail_io_timeout);
+
+static int __init setup_fail_io_timeout(char *str)
+{
+ return setup_fault_attr(&fail_io_timeout, str);
+}
+__setup("fail_io_timeout=", setup_fail_io_timeout);
+
+int blk_should_fake_timeout(struct request_queue *q)
+{
+ if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags))
+ return 0;
+
+ return should_fail(&fail_io_timeout, 1);
+}
+
+static int __init fail_io_timeout_debugfs(void)
+{
+ return init_fault_attr_dentries(&fail_io_timeout, "fail_io_timeout");
+}
+
+late_initcall(fail_io_timeout_debugfs);
+
+ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags);
+
+ return sprintf(buf, "%d\n", set != 0);
+}
+
+ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ int val;
+
+ if (count) {
+ struct request_queue *q = disk->queue;
+ char *p = (char *) buf;
+
+ val = simple_strtoul(p, &p, 10);
+ spin_lock_irq(q->queue_lock);
+ if (val)
+ queue_flag_set(QUEUE_FLAG_FAIL_IO, q);
+ else
+ queue_flag_clear(QUEUE_FLAG_FAIL_IO, q);
+ spin_unlock_irq(q->queue_lock);
+ }
+
+ return count;
+}
+
+#endif /* CONFIG_FAIL_IO_TIMEOUT */
+
/*
* blk_delete_timer - Delete/cancel timer for a given function.
* @req: request that we are canceling timer for