dm integrity: use dm_bio_record and dm_bio_restore

In cases where dec_in_flight() has to requeue the integrity_bio_wait
work to transfer the rest of the data, the bio's __bi_remaining might
already have been decremented to 0, e.g.: if bio passed to underlying
data device was split via blk_queue_split().

Use dm_bio_{record,restore} rather than effectively open-coding them in
dm-integrity -- these methods now manage __bi_remaining too.

Depends-on: f7f0b057a9c1 ("dm bio record: save/restore bi_end_io and bi_integrity")
Reported-by: Daniel Glöckner <dg@emlix.com>
Suggested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-integrity.c

@@ -6,6 +6,8 @@
  * This file is released under the GPL.
  */
 
+#include "dm-bio-record.h"
+
 #include <linux/compiler.h>
 #include <linux/module.h>
 #include <linux/device-mapper.h>
@@ -295,11 +297,7 @@ struct dm_integrity_io {
 
 	struct completion *completion;
 
-	struct gendisk *orig_bi_disk;
-	u8 orig_bi_partno;
-	bio_end_io_t *orig_bi_end_io;
-	struct bio_integrity_payload *orig_bi_integrity;
-	struct bvec_iter orig_bi_iter;
+	struct dm_bio_details bio_details;
 };
 
 struct journal_completion {
@@ -1452,14 +1450,9 @@ static void integrity_end_io(struct bio *bio)
 {
 	struct dm_integrity_io *dio = dm_per_bio_data(bio, sizeof(struct dm_integrity_io));
 
-	bio->bi_iter = dio->orig_bi_iter;
-	bio->bi_disk = dio->orig_bi_disk;
-	bio->bi_partno = dio->orig_bi_partno;
-	if (dio->orig_bi_integrity) {
-		bio->bi_integrity = dio->orig_bi_integrity;
+	dm_bio_restore(&dio->bio_details, bio);
+	if (bio->bi_integrity)
 		bio->bi_opf |= REQ_INTEGRITY;
-	}
-	bio->bi_end_io = dio->orig_bi_end_io;
 
 	if (dio->completion)
 		complete(dio->completion);
@@ -1544,7 +1537,7 @@ static void integrity_metadata(struct work_struct *w)
 			}
 		}
 
-		__bio_for_each_segment(bv, bio, iter, dio->orig_bi_iter) {
+		__bio_for_each_segment(bv, bio, iter, dio->bio_details.bi_iter) {
 			unsigned pos;
 			char *mem, *checksums_ptr;
 
@@ -1588,7 +1581,7 @@ static void integrity_metadata(struct work_struct *w)
 		if (likely(checksums != checksums_onstack))
 			kfree(checksums);
 	} else {
-		struct bio_integrity_payload *bip = dio->orig_bi_integrity;
+		struct bio_integrity_payload *bip = dio->bio_details.bi_integrity;
 
 		if (bip) {
 			struct bio_vec biv;
@@ -2007,20 +2000,13 @@ static void dm_integrity_map_continue(struct dm_integrity_io *dio, bool from_map
 	} else
 		dio->completion = NULL;
 
-	dio->orig_bi_iter = bio->bi_iter;
-
-	dio->orig_bi_disk = bio->bi_disk;
-	dio->orig_bi_partno = bio->bi_partno;
+	dm_bio_record(&dio->bio_details, bio);
 	bio_set_dev(bio, ic->dev->bdev);
-
-	dio->orig_bi_integrity = bio_integrity(bio);
 	bio->bi_integrity = NULL;
 	bio->bi_opf &= ~REQ_INTEGRITY;
-
-	dio->orig_bi_end_io = bio->bi_end_io;
 	bio->bi_end_io = integrity_end_io;
-
 	bio->bi_iter.bi_size = dio->range.n_sectors << SECTOR_SHIFT;
+
 	generic_make_request(bio);
 
 	if (need_sync_io) {