Having struct bio allows us to do more in the genrate/verify_fn,
like copying a known good guard tag already available rather than
calculating it.

Index: linux-3.10.0-862.9.1.el7/fs/bio-integrity.c
===================================================================
--- linux-3.10.0-862.9.1.el7.orig/fs/bio-integrity.c
+++ linux-3.10.0-862.9.1.el7/fs/bio-integrity.c
@@ -334,6 +334,8 @@ static void bio_integrity_generate(struc
 		bix.data_size = bv->bv_len;
 		bix.prot_buf = prot_buf;
 		bix.sector = sector;
+		bix.bio = bio;
+		bix.bi_idx = i;
 
 		generate_fn(&bix);
 
@@ -485,6 +487,8 @@ static int bio_integrity_verify(struct b
 		bix.data_size = bv->bv_len;
 		bix.prot_buf = prot_buf;
 		bix.sector = sector;
+		bix.bio = bio;
+		bix.bi_idx = i;
 
 		ret = verify_fn(&bix);
 
Index: linux-3.10.0-862.9.1.el7/include/linux/blkdev.h
===================================================================
--- linux-3.10.0-862.9.1.el7.orig/include/linux/blkdev.h
+++ linux-3.10.0-862.9.1.el7/include/linux/blkdev.h
@@ -1696,8 +1696,10 @@ static inline uint64_t rq_io_start_time_
 struct blk_integrity_exchg {
 	void			*prot_buf;
 	void			*data_buf;
+	struct bio		*bio;
 	sector_t		sector;
 	unsigned int		data_size;
+	unsigned int		bi_idx;
 	unsigned short		sector_size;
 	const char		*disk_name;
 };