1 files changed, 107 insertions, 0 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8874a63ae952..3e5dc87e0cfc 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -28,6 +28,7 @@
 #include <linux/crash_dump.h>
 #include <linux/prefetch.h>
 #include <linux/blk-crypto.h>
+#include <linux/sched/sysctl.h>
 
 #include <trace/events/block.h>
 
@@ -1058,6 +1059,112 @@ void blk_mq_start_request(struct request *rq)
 }
 EXPORT_SYMBOL(blk_mq_start_request);
 
+/**
+ * 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, blk_status_t error)
+{
+	struct completion *waiting = rq->end_io_data;
+
+	rq->end_io_data = (void *)(uintptr_t)error;
+
+	/*
+	 * 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 to I/O scheduler for execution
+ * @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 gendisk *bd_disk, struct request *rq,
+			   int at_head, rq_end_io_fn *done)
+{
+	WARN_ON(irqs_disabled());
+	WARN_ON(!blk_rq_is_passthrough(rq));
+
+	rq->rq_disk = bd_disk;
+	rq->end_io = done;
+
+	blk_account_io_start(rq);
+
+	/*
+	 * don't check dying flag for MQ because the request won't
+	 * be reused after dying flag is set
+	 */
+	blk_mq_sched_insert_request(rq, at_head, true, false);
+}
+EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
+
+static bool blk_rq_is_poll(struct request *rq)
+{
+	if (!rq->mq_hctx)
+		return false;
+	if (rq->mq_hctx->type != HCTX_TYPE_POLL)
+		return false;
+	if (WARN_ON_ONCE(!rq->bio))
+		return false;
+	return true;
+}
+
+static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
+{
+	do {
+		bio_poll(rq->bio, NULL, 0);
+		cond_resched();
+	} while (!completion_done(wait));
+}
+
+/**
+ * blk_execute_rq - insert a request into queue for execution
+ * @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.
+ * Return: The blk_status_t result provided to blk_mq_end_request().
+ */
+blk_status_t blk_execute_rq(struct gendisk *bd_disk, struct request *rq,
+		int at_head)
+{
+	DECLARE_COMPLETION_ONSTACK(wait);
+	unsigned long hang_check;
+
+	rq->end_io_data = &wait;
+	blk_execute_rq_nowait(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 (blk_rq_is_poll(rq))
+		blk_rq_poll_completion(rq, &wait);
+	else if (hang_check)
+		while (!wait_for_completion_io_timeout(&wait,
+				hang_check * (HZ/2)))
+			;
+	else
+		wait_for_completion_io(&wait);
+
+	return (blk_status_t)(uintptr_t)rq->end_io_data;
+}
+EXPORT_SYMBOL(blk_execute_rq);
+
 static void __blk_mq_requeue_request(struct request *rq)
 {
 	struct request_queue *q = rq->q;