diff -ur lin_tape-3.0.18/Makefile lin_tape-3.0.18-ifdefs/Makefile
--- lin_tape-3.0.18/Makefile	2017-05-09 21:11:32.977092391 +0200
+++ lin_tape-3.0.18-ifdefs/Makefile	2017-05-09 21:05:59.610307494 +0200
@@ -20,15 +20,6 @@
 lin_tape-objs := join.o lin_tape_scsi_config.o lin_tape_scsi_tape.o lin_tape_scsi_trace.o \
              lin_tape_ioctl_tape.o lin_tape_ioctl_changer.o lin_tape_extra_ioctl.o
 
-RHELRELEASE := $(shell [ -f "/etc/redhat-release" ] && echo 1 || echo 0)
-ifeq ($(RHELRELEASE), 1)
-KERNELDIR ?= /lib/modules/$(shell uname -r)/build
-KERNELVER = $(shell uname -r 2>/dev/null|sed "s/[\.-]/_/g"|sed "s/\([0-9]*_[0-9]*_[0-9]*_[0-9]*\).*/\1/")
-EXTRA_CFLAGS += -DKERNELVERSION_${KERNELVER}
-else
-EXTRA_CFLAGS += -DSLESVERSION
-endif
-
 ifeq ($(SFMP), 1)
 EXTRA_CFLAGS += -DSFMPENABLED
 endif
diff -ur lin_tape-3.0.18/pfo.h lin_tape-3.0.18-ifdefs/pfo.h
--- lin_tape-3.0.18/pfo.h	2017-02-23 19:14:41.000000000 +0100
+++ lin_tape-3.0.18-ifdefs/pfo.h	2017-05-09 21:06:34.117699008 +0200
@@ -26,109 +26,6 @@
  * will build for various releases of Linux.  This is how
  * we track different versions using ifdef in the source.
  */
-#ifdef KERNELVERSION_2_6_32_220
-#define BEFORE_RH_63 1
-#define BEFORE_RH_64 1
-#define BEFORE_RH_65 1
-#define BEFORE_RH_66 1
-#define BEFORE_RH_67 1
-#define BEFORE_RH_70 1
-#define BEFORE_RH_71 1
-#define BEFORE_RH_72 1
-#endif
-#ifdef KERNELVERSION_2_6_32_279
-#define AFTER_RH_62 1
-#define BEFORE_RH_64 1
-#define BEFORE_RH_65 1
-#define BEFORE_RH_66 1
-#define BEFORE_RH_67 1
-#define BEFORE_RH_70 1
-#define BEFORE_RH_71 1
-#define BEFORE_RH_72 1
-#endif
-#ifdef KERNELVERSION_2_6_32_358
-#define AFTER_RH_62 1
-#define AFTER_RH_63 1
-#define BEFORE_RH_65 1
-#define BEFORE_RH_66 1
-#define BEFORE_RH_67 1
-#define BEFORE_RH_70 1
-#define BEFORE_RH_72 1
-#endif
-#ifdef KERNELVERSION_2_6_32_431
-#define AFTER_RH_62 1
-#define AFTER_RH_63 1
-#define AFTER_RH_64 1
-#define BEFORE_RH_66 1
-#define BEFORE_RH_67 1
-#define BEFORE_RH_70 1
-#define BEFORE_RH_71 1
-#define BEFORE_RH_72 1
-#endif
-#ifdef KERNELVERSION_2_6_32_504
-#define AFTER_RH_62 1
-#define AFTER_RH_63 1
-#define AFTER_RH_64 1
-#define AFTER_RH_65 1
-#define BEFORE_RH_67 1
-#define BEFORE_RH_70 1
-#define BEFORE_RH_71 1
-#define BEFORE_RH_72 1
-#endif
-#ifdef KERNELVERSION_2_6_32_573
-#define AFTER_RH_62 1
-#define AFTER_RH_63 1
-#define AFTER_RH_64 1
-#define AFTER_RH_65 1
-#define AFTER_RH_66 1
-#define BEFORE_RH_70 1
-#define BEFORE_RH_71 1
-#define BEFORE_RH_72 1
-#endif
-#ifdef KERNELVERSION_2_6_32_642
-#define AFTER_RH_62 1
-#define AFTER_RH_63 1
-#define AFTER_RH_64 1
-#define AFTER_RH_65 1
-#define AFTER_RH_66 1
-#define AFTER_RH_67 1
-#define BEFORE_RH_70 1
-#define BEFORE_RH_71 1
-#define BEFORE_RH_72 1
-#endif
-#ifdef KERNELVERSION_3_10_0_123
-#define AFTER_RH_62 1
-#define AFTER_RH_63 1
-#define AFTER_RH_64 1
-#define AFTER_RH_65 1
-#define AFTER_RH_66 1
-#define AFTER_RH_67 1
-#define AFTER_RH_6x 1
-#define BEFORE_RH_71 1
-#endif
-#ifdef KERNELVERSION_3_10_0_229
-#define AFTER_RH_62 1
-#define AFTER_RH_63 1
-#define AFTER_RH_64 1
-#define AFTER_RH_65 1
-#define AFTER_RH_66 1
-#define AFTER_RH_67 1
-#define AFTER_RH_6x 1
-#define AFTER_RH_70 1
-#define BEFORE_RH_72 1
-#endif
-#ifdef KERNELVERSION_3_10_0_327
-#define AFTER_RH_62 1
-#define AFTER_RH_63 1
-#define AFTER_RH_64 1
-#define AFTER_RH_65 1
-#define AFTER_RH_66 1
-#define AFTER_RH_67 1
-#define AFTER_RH_6x 1
-#define AFTER_RH_70 1
-#define AFTER_RH_71 1
-#endif
-#ifdef KERNELVERSION_3_10_0_514
 #define AFTER_RH_62 1
 #define AFTER_RH_63 1
 #define AFTER_RH_64 1
@@ -126,7 +35,6 @@
 #define AFTER_RH_70 1
 #define AFTER_RH_71 1
 #define AFTER_RH_72 1
-#endif
 
 /* Misc defines needed so source is same for all versions of Linux */
 #ifndef SDEV_TRANSPORT_OFFLINE
diff -ur lin_tape-3.0.18/sgmp.c lin_tape-3.0.18-ifdefs/sgmp.c
--- lin_tape-3.0.18/sgmp.c	2017-02-23 19:14:41.000000000 +0100
+++ lin_tape-3.0.18-ifdefs/sgmp.c	2017-05-09 21:10:20.295643954 +0200
@@ -262,27 +262,12 @@
 {
 	struct sg_fd *sfp = (struct sg_fd *)filp->private_data;
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,10,0) && (!defined(SLESVERSION))
-	/* RHEL 7.0 and beyond */
 	struct request_queue *q = sfp->parentdp->device->request_queue;
-#else
-#ifdef AFTER_RH_63
-	/* RHEL 6.4+ */
-	struct request_queue *q = sfp->parentdp->device->request_queue;
-#endif
-#endif
 
 	if (sfp->parentdp->device->type == TYPE_SCANNER)
 		return 0;
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(3,12,0) || defined(SLESVERSION)
 	return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
-#else
-	/* RHEL 6.4 and beyond */
-	return blk_verify_command(q, cmd, filp->f_mode & FMODE_WRITE);
-#endif
-//6.3 blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
-
 }
 
 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,32)
@@ -419,7 +404,7 @@
 #endif
 		sdp->sgdebug = 0;
 		q = sdp->device->request_queue;
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,32) && (defined(SLESVERSION))
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,32)
 		sdp->sg_tablesize = min(queue_max_hw_segments(q),
                                 queue_max_phys_segments(q));
 #else
@@ -1546,7 +1531,7 @@
 		if ((sdp->sgdebug > 0) &&
 		    ((CHECK_CONDITION == srp->header.masked_status) ||
 		     (COMMAND_TERMINATED == srp->header.masked_status)))
-#if defined(AFTER_RH_71) || LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,21)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,21)
 			__scsi_print_sense(sdp->device, "sg_cmd_done", sense, SCSI_SENSE_BUFFERSIZE);
 
 #else
@@ -1677,7 +1662,7 @@
 	INIT_LIST_HEAD(&sdp->sfds);
 	init_waitqueue_head(&sdp->o_excl_wait);
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,32) && (defined(SLESVERSION))
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,32)
 	sdp->sg_tablesize = min(queue_max_hw_segments(q),
                             queue_max_phys_segments(q));
 #else
@@ -3069,7 +3054,7 @@
 			      scsidp->id, scsidp->lun, (int) scsidp->type,
 			      1,
 			      (int) scsidp->queue_depth,
-#ifdef AFTER_RH_71
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,19,0)
 				  (int) atomic_read(&scsidp->device_busy),
 #else
 				  (int) scsidp->device_busy,
diff -ur lin_tape-3.0.18/stmp.c lin_tape-3.0.18-ifdefs/stmp.c
--- lin_tape-3.0.18/stmp.c	2017-02-23 19:14:41.000000000 +0100
+++ lin_tape-3.0.18-ifdefs/stmp.c	2017-05-09 21:11:01.113125428 +0200
@@ -454,7 +454,7 @@
 		       SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 		       SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 		if (cmdstatp->have_sense)
-#if defined(AFTER_RH_70) || LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,21)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,21)
 			__scsi_print_sense(STp->device, name, SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 
 #else
@@ -475,7 +475,7 @@
 			 SRpnt->cmd[0] != MODE_SENSE &&
 			 SRpnt->cmd[0] != TEST_UNIT_READY) {
 
-#if defined(AFTER_RH_71) || LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,21)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,21)
 			__scsi_print_sense(STp->device, name, SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 
 #else
diff -ur lin_tape-3.0.18/upper.c lin_tape-3.0.18-ifdefs/upper.c
--- lin_tape-3.0.18/upper.c	2017-02-23 19:14:41.000000000 +0100
+++ lin_tape-3.0.18-ifdefs/upper.c	2017-05-09 21:09:37.868126006 +0200
@@ -267,7 +267,7 @@
 	if (copy_from_user(pfo_cmd->scsi_cmd, hdr->cmdp, hdr->cmd_len))
 		return -EFAULT;
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(3,12,0) || defined(SLESVERSION)
+#if LINUX_VERSION_CODE > KERNEL_VERSION(3,12,0)
 	if (blk_verify_command(pfo_cmd->scsi_cmd, mode & FMODE_WRITE))
 #else
 	/* RHEL 6.4 and beyond */
@@ -608,7 +608,7 @@
 	if (in_len && copy_from_user(buffer, sic->data + cmdlen, in_len))
 		goto error;
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(3,12,0) || defined(SLESVERSION)
+#if LINUX_VERSION_CODE > KERNEL_VERSION(3,12,0)
 	err = blk_verify_command(scsi_cmd, mode & FMODE_WRITE);
 #else
 	/* RHEL 6.4 and beyond */