[SCSI] lib: Add support for the T10 (SCSI) Data Integrity Field CRC

The SCSI Block Protocol uses this 16-bit CRC to verify the integrity
of each data sector.  crc_t10dif() is used by sd_dif.c when performing
I/O to or from disks formatted with protection information.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/lib/Kconfig b/lib/Kconfig
index 8cc8e87..c7ad7a5 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -29,6 +29,13 @@
 	  the kernel tree does. Such modules that use library CRC16
 	  functions require M here.
 
+config CRC_T10DIF
+	tristate "CRC calculation for the T10 Data Integrity Field"
+	help
+	  This option is only needed if a module that's not in the
+	  kernel tree needs to calculate CRC checks for use with the
+	  SCSI data integrity subsystem.
+
 config CRC_ITU_T
 	tristate "CRC ITU-T V.41 functions"
 	help