Merge tag 'for-5.19/block-exec-2022-06-02' of git://git.kernel.dk/linux-block

Pull block request execute cleanups from Jens Axboe:
 "This change was advertised in the initial core block pull request, but
  didn't actually make that branch as we deferred it to a post-merge
  pull request to avoid a bunch of cross branch issues.

  This series cleans up the block execute path quite nicely"

* tag 'for-5.19/block-exec-2022-06-02' of git://git.kernel.dk/linux-block:
  blk-mq: remove the done argument to blk_execute_rq_nowait
  blk-mq: avoid a mess of casts for blk_end_sync_rq
  blk-mq: remove __blk_execute_rq_nowait

1 files changed, 49 insertions, 64 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 30e4bdcd8d7f..e9bf950983c7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1152,24 +1152,6 @@ 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);
-}
-
 /*
  * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
  * queues. This is important for md arrays to benefit from merging
@@ -1204,33 +1186,10 @@ static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
 	plug->rq_count++;
 }
 
-static void __blk_execute_rq_nowait(struct request *rq, bool at_head,
-		rq_end_io_fn *done, bool use_plug)
-{
-	WARN_ON(irqs_disabled());
-	WARN_ON(!blk_rq_is_passthrough(rq));
-
-	rq->end_io = done;
-
-	blk_account_io_start(rq);
-
-	if (use_plug && current->plug) {
-		blk_add_rq_to_plug(current->plug, rq);
-		return;
-	}
-	/*
-	 * 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);
-}
-
-
 /**
  * blk_execute_rq_nowait - insert a request to I/O scheduler for execution
  * @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
@@ -1239,13 +1198,32 @@ static void __blk_execute_rq_nowait(struct request *rq, bool at_head,
  * Note:
  *    This function will invoke @done directly if the queue is dead.
  */
-void blk_execute_rq_nowait(struct request *rq, bool at_head, rq_end_io_fn *done)
+void blk_execute_rq_nowait(struct request *rq, bool at_head)
 {
-	__blk_execute_rq_nowait(rq, at_head, done, true);
+	WARN_ON(irqs_disabled());
+	WARN_ON(!blk_rq_is_passthrough(rq));
 
+	blk_account_io_start(rq);
+	if (current->plug)
+		blk_add_rq_to_plug(current->plug, rq);
+	else
+		blk_mq_sched_insert_request(rq, at_head, true, false);
 }
 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
 
+struct blk_rq_wait {
+	struct completion done;
+	blk_status_t ret;
+};
+
+static void blk_end_sync_rq(struct request *rq, blk_status_t ret)
+{
+	struct blk_rq_wait *wait = rq->end_io_data;
+
+	wait->ret = ret;
+	complete(&wait->done);
+}
+
 static bool blk_rq_is_poll(struct request *rq)
 {
 	if (!rq->mq_hctx)
@@ -1277,30 +1255,37 @@ static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
  */
 blk_status_t blk_execute_rq(struct request *rq, bool at_head)
 {
-	DECLARE_COMPLETION_ONSTACK(wait);
-	unsigned long hang_check;
+	struct blk_rq_wait wait = {
+		.done = COMPLETION_INITIALIZER_ONSTACK(wait.done),
+	};
+
+	WARN_ON(irqs_disabled());
+	WARN_ON(!blk_rq_is_passthrough(rq));
 
-	/*
-	 * iopoll requires request to be submitted to driver, so can't
-	 * use plug
-	 */
 	rq->end_io_data = &wait;
-	__blk_execute_rq_nowait(rq, at_head, blk_end_sync_rq,
-			!blk_rq_is_poll(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);
+	rq->end_io = blk_end_sync_rq;
+
+	blk_account_io_start(rq);
+	blk_mq_sched_insert_request(rq, at_head, true, false);
+
+	if (blk_rq_is_poll(rq)) {
+		blk_rq_poll_completion(rq, &wait.done);
+	} else {
+		/*
+		 * Prevent hang_check timer from firing at us during very long
+		 * I/O
+		 */
+		unsigned long hang_check = sysctl_hung_task_timeout_secs;
+
+		if (hang_check)
+			while (!wait_for_completion_io_timeout(&wait.done,
+					hang_check * (HZ/2)))
+				;
+		else
+			wait_for_completion_io(&wait.done);
+	}
 
-	return (blk_status_t)(uintptr_t)rq->end_io_data;
+	return wait.ret;
 }
 EXPORT_SYMBOL(blk_execute_rq);