1 files changed, 238 insertions, 0 deletions

diff --git a/block/blk-timeout.c b/block/blk-timeout.c
new file mode 100644
index 000000000000..972a63f848fb
--- /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);