Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / block / blk-exec.c

diff --git a/kernel/block/blk-exec.c b/kernel/block/blk-exec.c
new file mode 100644 (file)
index 0000000..9924725
--- /dev/null
+++ b/kernel/block/blk-exec.c
@@ -0,0 +1,143 @@
+/*
+ * Functions related to setting various queue properties from drivers
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/sched/sysctl.h>
+
+#include "blk.h"
+
+/*
+ * for max sense size
+ */
+#include <scsi/scsi_cmnd.h>
+
+/**
+ * blk_end_sync_rq - executes a completion event on a request
+ * @rq: request to complete
+ * @error: end I/O status of the request
+ */
+static void blk_end_sync_rq(struct request *rq, int error)
+{
+       struct completion *waiting = rq->end_io_data;
+
+       rq->end_io_data = NULL;
+
+       /*
+        * complete last, if this is a stack request the process (and thus
+        * the rq pointer) could be invalid right after this complete()
+        */
+       complete(waiting);
+}
+
+/**
+ * blk_execute_rq_nowait - insert a request into queue for execution
+ * @q:         queue to insert the request in
+ * @bd_disk:   matching gendisk
+ * @rq:                request to insert
+ * @at_head:    insert request at head or tail of queue
+ * @done:      I/O completion handler
+ *
+ * Description:
+ *    Insert a fully prepared request at the back of the I/O scheduler queue
+ *    for execution.  Don't wait for completion.
+ *
+ * Note:
+ *    This function will invoke @done directly if the queue is dead.
+ */
+void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
+                          struct request *rq, int at_head,
+                          rq_end_io_fn *done)
+{
+       int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
+       bool is_pm_resume;
+
+       WARN_ON(irqs_disabled());
+       WARN_ON(rq->cmd_type == REQ_TYPE_FS);
+
+       rq->rq_disk = bd_disk;
+       rq->end_io = done;
+
+       /*
+        * don't check dying flag for MQ because the request won't
+        * be resued after dying flag is set
+        */
+       if (q->mq_ops) {
+               blk_mq_insert_request(rq, at_head, true, false);
+               return;
+       }
+
+       /*
+        * need to check this before __blk_run_queue(), because rq can
+        * be freed before that returns.
+        */
+       is_pm_resume = rq->cmd_type == REQ_TYPE_PM_RESUME;
+
+       spin_lock_irq(q->queue_lock);
+
+       if (unlikely(blk_queue_dying(q))) {
+               rq->cmd_flags |= REQ_QUIET; 
+               rq->errors = -ENXIO;
+               __blk_end_request_all(rq, rq->errors);
+               spin_unlock_irq(q->queue_lock);
+               return;
+       }
+
+       __elv_add_request(q, rq, where);
+       __blk_run_queue(q);
+       /* the queue is stopped so it won't be run */
+       if (is_pm_resume)
+               __blk_run_queue_uncond(q);
+       spin_unlock_irq(q->queue_lock);
+}
+EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
+
+/**
+ * blk_execute_rq - insert a request into queue for execution
+ * @q:         queue to insert the request in
+ * @bd_disk:   matching gendisk
+ * @rq:                request to insert
+ * @at_head:    insert request at head or tail of queue
+ *
+ * Description:
+ *    Insert a fully prepared request at the back of the I/O scheduler queue
+ *    for execution and wait for completion.
+ */
+int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
+                  struct request *rq, int at_head)
+{
+       DECLARE_COMPLETION_ONSTACK(wait);
+       char sense[SCSI_SENSE_BUFFERSIZE];
+       int err = 0;
+       unsigned long hang_check;
+
+       if (!rq->sense) {
+               memset(sense, 0, sizeof(sense));
+               rq->sense = sense;
+               rq->sense_len = 0;
+       }
+
+       rq->end_io_data = &wait;
+       blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
+
+       /* Prevent hang_check timer from firing at us during very long I/O */
+       hang_check = sysctl_hung_task_timeout_secs;
+       if (hang_check)
+               while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
+       else
+               wait_for_completion_io(&wait);
+
+       if (rq->errors)
+               err = -EIO;
+
+       if (rq->sense == sense) {
+               rq->sense = NULL;
+               rq->sense_len = 0;
+       }
+
+       return err;
+}
+EXPORT_SYMBOL(blk_execute_rq);