block: add fault injection mechanism for faking request timeouts

[linux-2.6-omap-h63xx.git] / block / blk-timeout.c

diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 6e5c781c5af1422c56c131285ae5d8af6893958c..9b4ad138bb33a4559a98fec2e0edc2136b8eff52 100644 (file)
--- 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