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-rw-r--r--block/blk-timeout.c238
1 files changed, 238 insertions, 0 deletions
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
new file mode 100644
index 0000000..972a63f
--- /dev/null
+++ b/block/blk-timeout.c
@@ -0,0 +1,238 @@
+/*
+ * Functions related to generic timeout handling of requests.
+ */
+#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
+ *
+ */
+void blk_delete_timer(struct request *req)
+{
+ struct request_queue *q = req->q;
+
+ /*
+ * Nothing to detach
+ */
+ if (!q->rq_timed_out_fn || !req->deadline)
+ return;
+
+ list_del_init(&req->timeout_list);
+
+ if (list_empty(&q->timeout_list))
+ del_timer(&q->timeout);
+}
+
+static void blk_rq_timed_out(struct request *req)
+{
+ struct request_queue *q = req->q;
+ enum blk_eh_timer_return ret;
+
+ ret = q->rq_timed_out_fn(req);
+ switch (ret) {
+ case BLK_EH_HANDLED:
+ __blk_complete_request(req);
+ break;
+ case BLK_EH_RESET_TIMER:
+ blk_clear_rq_complete(req);
+ blk_add_timer(req);
+ break;
+ case BLK_EH_NOT_HANDLED:
+ /*
+ * LLD handles this for now but in the future
+ * we can send a request msg to abort the command
+ * and we can move more of the generic scsi eh code to
+ * the blk layer.
+ */
+ break;
+ default:
+ printk(KERN_ERR "block: bad eh return: %d\n", ret);
+ break;
+ }
+}
+
+void blk_rq_timed_out_timer(unsigned long data)
+{
+ struct request_queue *q = (struct request_queue *) data;
+ unsigned long flags, uninitialized_var(next), next_set = 0;
+ struct request *rq, *tmp;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+
+ list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) {
+ if (time_after_eq(jiffies, rq->deadline)) {
+ list_del_init(&rq->timeout_list);
+
+ /*
+ * Check if we raced with end io completion
+ */
+ if (blk_mark_rq_complete(rq))
+ continue;
+ blk_rq_timed_out(rq);
+ }
+ if (!next_set) {
+ next = rq->deadline;
+ next_set = 1;
+ } else if (time_after(next, rq->deadline))
+ next = rq->deadline;
+ }
+
+ if (next_set && !list_empty(&q->timeout_list))
+ mod_timer(&q->timeout, round_jiffies(next));
+
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+/**
+ * blk_abort_request -- Request request recovery for the specified command
+ * @req: pointer to the request of interest
+ *
+ * This function requests that the block layer start recovery for the
+ * request by deleting the timer and calling the q's timeout function.
+ * LLDDs who implement their own error recovery MAY ignore the timeout
+ * event if they generated blk_abort_req. Must hold queue lock.
+ */
+void blk_abort_request(struct request *req)
+{
+ if (blk_mark_rq_complete(req))
+ return;
+ blk_delete_timer(req);
+ blk_rq_timed_out(req);
+}
+EXPORT_SYMBOL_GPL(blk_abort_request);
+
+/**
+ * blk_add_timer - Start timeout timer for a single request
+ * @req: request that is about to start running.
+ *
+ * Notes:
+ * Each request has its own timer, and as it is added to the queue, we
+ * set up the timer. When the request completes, we cancel the timer.
+ */
+void blk_add_timer(struct request *req)
+{
+ struct request_queue *q = req->q;
+ unsigned long expiry;
+
+ if (!q->rq_timed_out_fn)
+ return;
+
+ BUG_ON(!list_empty(&req->timeout_list));
+ BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
+
+ if (req->timeout)
+ req->deadline = jiffies + req->timeout;
+ else {
+ req->deadline = jiffies + q->rq_timeout;
+ /*
+ * Some LLDs, like scsi, peek at the timeout to prevent
+ * a command from being retried forever.
+ */
+ req->timeout = q->rq_timeout;
+ }
+ list_add_tail(&req->timeout_list, &q->timeout_list);
+
+ /*
+ * If the timer isn't already pending or this timeout is earlier
+ * than an existing one, modify the timer. Round to next nearest
+ * second.
+ */
+ expiry = round_jiffies(req->deadline);
+
+ /*
+ * We use ->deadline == 0 to detect whether a timer was added or
+ * not, so just increase to next jiffy for that specific case
+ */
+ if (unlikely(!req->deadline))
+ req->deadline = 1;
+
+ if (!timer_pending(&q->timeout) ||
+ time_before(expiry, q->timeout.expires))
+ mod_timer(&q->timeout, expiry);
+}
+
+/**
+ * blk_abort_queue -- Abort all request on given queue
+ * @queue: pointer to queue
+ *
+ */
+void blk_abort_queue(struct request_queue *q)
+{
+ unsigned long flags;
+ struct request *rq, *tmp;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+
+ elv_abort_queue(q);
+
+ list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list)
+ blk_abort_request(rq);
+
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+}
+EXPORT_SYMBOL_GPL(blk_abort_queue);
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