fs/buffer: remove bh_submit_read() helper

Bugzilla: https://bugzilla.redhat.com/2160719
Tested: xfstests
Upstream Status: upstream

commit 454552d
Author: Zhang Yi <yi.zhang@huawei.com>
    
    bh_submit_read() has no user anymore, just remove it.
    
    Link: https://lkml.kernel.org/r/20220901133505.2510834-15-yi.zhang@huawei.com
    Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
    Reviewed-by: Jan Kara <jack@suse.cz>
    Reviewed-by: Christoph Hellwig <hch@lst.de>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    (cherry picked from commit 454552d)
    Signed-off-by: Lukas Czerner <lczerner@redhat.com>

Signed-off-by: Lukas Czerner <lczerner@redhat.com>

Author: Lukas Czerner

fs/buffer.c

@@ -3352,31 +3352,6 @@ void __bh_read_batch(int nr, struct buffer_head *bhs[],
 }
 EXPORT_SYMBOL(__bh_read_batch);
 
-/**
- * bh_submit_read - Submit a locked buffer for reading
- * @bh: struct buffer_head
- *
- * Returns zero on success and -EIO on error.
- */
-int bh_submit_read(struct buffer_head *bh)
-{
-	BUG_ON(!buffer_locked(bh));
-
-	if (buffer_uptodate(bh)) {
-		unlock_buffer(bh);
-		return 0;
-	}
-
-	get_bh(bh);
-	bh->b_end_io = end_buffer_read_sync;
-	submit_bh(REQ_OP_READ, bh);
-	wait_on_buffer(bh);
-	if (buffer_uptodate(bh))
-		return 0;
-	return -EIO;
-}
-EXPORT_SYMBOL(bh_submit_read);
-
 void __init buffer_init(void)
 {
 	unsigned long nrpages;

include/linux/buffer_head.h

@@ -230,7 +230,6 @@ int submit_bh(blk_opf_t, struct buffer_head *);
 void write_boundary_block(struct block_device *bdev,
 			sector_t bblock, unsigned blocksize);
 int bh_uptodate_or_lock(struct buffer_head *bh);
-int bh_submit_read(struct buffer_head *bh);
 int __bh_read(struct buffer_head *bh, blk_opf_t op_flags, bool wait);
 void __bh_read_batch(int nr, struct buffer_head *bhs[],
 		     blk_opf_t op_flags, bool force_lock);