From 8c579ab69d50a416887390ba4b89598a7b2fa0b6 Mon Sep 17 00:00:00 2001
From: "Martin K. Petersen" <martin.petersen@oracle.com>
Date: Tue, 28 Aug 2012 14:29:33 -0400
Subject: [SCSI] sd: Avoid remapping bad reference tags

It does not make sense to translate ref tags with unexpected values.
Instead we simply ignore them and let the upper layers catch the
problem. Ref tags that contain the expected value are still remapped.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 4df73e5..9f7fc39 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -804,9 +804,8 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
 		SCpnt->cmnd[0] = WRITE_6;
 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
 
-		if (blk_integrity_rq(rq) &&
-		    sd_dif_prepare(rq, block, sdp->sector_size) == -EIO)
-			goto out;
+		if (blk_integrity_rq(rq))
+			sd_dif_prepare(rq, block, sdp->sector_size);
 
 	} else if (rq_data_dir(rq) == READ) {
 		SCpnt->cmnd[0] = READ_6;
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index f703f48..47c52a6 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -156,7 +156,7 @@ struct sd_dif_tuple {
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 
 extern void sd_dif_config_host(struct scsi_disk *);
-extern int sd_dif_prepare(struct request *rq, sector_t, unsigned int);
+extern void sd_dif_prepare(struct request *rq, sector_t, unsigned int);
 extern void sd_dif_complete(struct scsi_cmnd *, unsigned int);
 
 #else /* CONFIG_BLK_DEV_INTEGRITY */
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index e52d5bc..04998f3 100644
--- a/drivers/scsi/sd_dif.c
+++ b/drivers/scsi/sd_dif.c
@@ -366,7 +366,8 @@ void sd_dif_config_host(struct scsi_disk *sdkp)
  *
  * Type 3 does not have a reference tag so no remapping is required.
  */
-int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_sz)
+void sd_dif_prepare(struct request *rq, sector_t hw_sector,
+		    unsigned int sector_sz)
 {
 	const int tuple_sz = sizeof(struct sd_dif_tuple);
 	struct bio *bio;
@@ -378,7 +379,7 @@ int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_s
 	sdkp = rq->bio->bi_bdev->bd_disk->private_data;
 
 	if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
-		return 0;
+		return;
 
 	phys = hw_sector & 0xffffffff;
 
@@ -397,10 +398,9 @@ int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_s
 
 			for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
 
-				if (be32_to_cpu(sdt->ref_tag) != virt)
-					goto error;
+				if (be32_to_cpu(sdt->ref_tag) == virt)
+					sdt->ref_tag = cpu_to_be32(phys);
 
-				sdt->ref_tag = cpu_to_be32(phys);
 				virt++;
 				phys++;
 			}
@@ -410,16 +410,6 @@ int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_s
 
 		bio->bi_flags |= (1 << BIO_MAPPED_INTEGRITY);
 	}
-
-	return 0;
-
-error:
-	kunmap_atomic(sdt);
-	sd_printk(KERN_ERR, sdkp, "%s: virt %u, phys %u, ref %u, app %4x\n",
-		  __func__, virt, phys, be32_to_cpu(sdt->ref_tag),
-		  be16_to_cpu(sdt->app_tag));
-
-	return -EILSEQ;
 }
 
 /*
@@ -463,10 +453,7 @@ void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
 					return;
 				}
 
-				if (be32_to_cpu(sdt->ref_tag) != phys &&
-				    sdt->app_tag != 0xffff)
-					sdt->ref_tag = 0xffffffff; /* Bad ref */
-				else
+				if (be32_to_cpu(sdt->ref_tag) == phys)
 					sdt->ref_tag = cpu_to_be32(virt);
 
 				virt++;
-- 
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