On Tue, Feb 23, 2021 at 02:34:37PM +1100, Dave Chinner wrote:

From: Dave Chinner <redacted>

Move it to xfs_bio_io.c as we are about to add new async cache flush
functionality that uses bios directly, so all this stuff should be
in the same place. Rename the function to xfs_flush_bdev() to match
the xfs_rw_bdev() function that already exists in this file.

I'd rather kill it off.  None that as of the latest Linus tree,
blkdev_issue_flush has also lost the gfp_mask argument.