There are use-cases like replication where need to hook the blk I/O
operations for devices and perform specific operation and fallback to
its original I/O operations.
Prior to v5.9 there was make_request_fn and then blk_mq_submit_bio
exported apis, which provided infrastructure to drivers to develop these
features. However in v5.10-rc1 with below commit the API was removed
from the export list.

Previous commit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.10-rc1&id=681cc5e8667e8579a2da8fa4090c48a2d73fc3bb

This patch exports the blk_mq_submit_bio symbol to provide flexibility
to the drivers.

Signed-off-by: Praveen Kumar <redacted>
---
 block/blk-mq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 65d3a63aecc6..40a9b085f029 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c

@@ -2283,6 +2283,7 @@ blk_qc_t blk_mq_submit_bio(struct bio *bio)
 	blk_queue_exit(q);
 	return BLK_QC_T_NONE;
 }
+EXPORT_SYMBOL_GPL(blk_mq_submit_bio);
 
 static size_t order_to_size(unsigned int order)
 {

-- 
2.25.1