block: Make the integrity mapped property a bio flag

Previously we tracked whether the integrity metadata had been remapped
using a request flag. This was fine for low-level retries. However, if
an I/O was redriven by upper layers we would end up remapping again,
causing the retry to fail.

Deprecate the REQ_INTEGRITY flag and introduce BIO_MAPPED_INTEGRITY
which enables filesystems to notify lower layers that the bio in
question has already been remapped.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index 84be621..0cb39ff 100644
--- a/drivers/scsi/sd_dif.c
+++ b/drivers/scsi/sd_dif.c
@@ -375,21 +375,20 @@
 	unsigned int i, j;
 	u32 phys, virt;
 
-	/* Already remapped? */
-	if (rq->cmd_flags & REQ_INTEGRITY)
-		return 0;
-
 	sdkp = rq->bio->bi_bdev->bd_disk->private_data;
 
 	if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
 		return 0;
 
-	rq->cmd_flags |= REQ_INTEGRITY;
 	phys = hw_sector & 0xffffffff;
 
 	__rq_for_each_bio(bio, rq) {
 		struct bio_vec *iv;
 
+		/* Already remapped? */
+		if (bio_flagged(bio, BIO_MAPPED_INTEGRITY))
+			break;
+
 		virt = bio->bi_integrity->bip_sector & 0xffffffff;
 
 		bip_for_each_vec(iv, bio->bi_integrity, i) {
@@ -408,6 +407,8 @@
 
 			kunmap_atomic(sdt, KM_USER0);
 		}
+
+		bio->bi_flags |= BIO_MAPPED_INTEGRITY;
 	}
 
 	return 0;