block: introduce pi_size field in blk_integrity

Introduce a new pi_size field in struct blk_integrity to explicitly
represent the size (in bytes) of the protection information (PI) tuple.
This is a prep patch.

Signed-off-by: Anuj Gupta <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>

Author: Anuj Gupta

drivers/nvme/host/core.c

@@ -1867,6 +1867,7 @@ static bool nvme_init_integrity(struct nvme_ns_head *head,
 	}
 
 	bi->tuple_size = head->ms;
+	bi->pi_size = head->pi_size;
 	bi->pi_offset = info->pi_offset;
 	return true;
 }

drivers/scsi/sd_dif.c

@@ -53,6 +53,7 @@ void sd_dif_config_host(struct scsi_disk *sdkp, struct queue_limits *lim)
 		bi->flags |= BLK_INTEGRITY_REF_TAG;
 
 	bi->tuple_size = sizeof(struct t10_pi_tuple);
+	bi->pi_size = bi->tuple_size;
 
 	if (dif && type) {
 		bi->flags |= BLK_INTEGRITY_DEVICE_CAPABLE;

include/linux/blkdev.h

@@ -120,6 +120,7 @@ struct blk_integrity {
 	unsigned char				pi_offset;
 	unsigned char				interval_exp;
 	unsigned char				tag_size;
+	unsigned char				pi_size;
 };
 
 typedef unsigned int __bitwise blk_mode_t;