diff --git a/scripts/generate-kernel-patch b/scripts/generate-kernel-patch
index cc95d7a67..d41d188e9 100755
--- a/scripts/generate-kernel-patch
+++ b/scripts/generate-kernel-patch
@@ -373,18 +373,33 @@ rm -rf "${tmpdir}"
 
 for s in ${separate_patches}
 do
-  fileset=$s
-  for f in $(set | grep "^$s=" | sed -e "s/^$s='\(.*\)'\$/\1/" -e "s/^$s=\(.*\)\$/\1/")
-  do
-    if [ "${f#scst/include}" != "${f}" ]; then
-      add_file "${f}" "include/scst/${f#scst/include/}"
-    elif [ "${f#doc}" != "${f}" ]; then
-      add_file "${f}" "Documentation/scst/${f#doc/}"
-    else
-      add_file "${f}" "drivers/scst/${f#scst/src/}"
+  {
+    fileset=$s
+    for f in $(set | grep "^$s=" | sed -e "s/^$s='\(.*\)'\$/\1/" -e "s/^$s=\(.*\)\$/\1/")
+    do
+      if [ "${f#scst/include}" != "${f}" ]; then
+	add_file "${f}" "include/scst/${f#scst/include/}"
+      elif [ "${f#doc}" != "${f}" ]; then
+	add_file "${f}" "Documentation/scst/${f#doc/}"
+      else
+	add_file "${f}" "drivers/scst/${f#scst/src/}"
+      fi
+    done
+    if grep -q /scst_itf_ver.h scst/src/Makefile &&
+       [ "$s" = "scst_03_public_headers" ]; then
+      tmp_itf_ver="$(mktemp /tmp/scst-itf-ver.h.XXXXXXXXXX)"
+      cat <<"EOF" >$tmp_itf_ver
+/* Autogenerated, don't edit */
+
+#define SCST_INTF_VER "SCST_INTF_VER"
+#define SCST_CONST_INTF_VER "SCST_CONST_INTF_VER"
+#define DEV_USER_INTF_VER "DEV_USER_INTF_VER"
+EOF
+      add_file "$tmp_itf_ver" "include/scst/scst_itf_ver.h"
+      rm -f "$tmp_itf_ver"
     fi
-  done \
-  | process_patch "${s}.diff"
+  } |
+  process_patch "${s}.diff"
 done
 
 {
diff --git a/scripts/rebuild-rhel-kernel-rpm b/scripts/rebuild-rhel-kernel-rpm
index 88c93d16d..e4a96c1d7 100755
--- a/scripts/rebuild-rhel-kernel-rpm
+++ b/scripts/rebuild-rhel-kernel-rpm
@@ -36,63 +36,51 @@
 #
 ############################################################################
 
-scst_dir="$(dirname "$(dirname "$0")")"
-if [ ${scst_dir:0:1} != "/" ]; then
-  scst_dir="$PWD/${scst_dir}"
+scriptdir="$(dirname "$0")"
+if [ "${scriptdir:0:1}" != "/" ]; then
+    scriptdir="$PWD/${scriptdir}"
 fi
+scriptdir="${scriptdir%/.}"
+source "${scriptdir}/rhel-rpm-functions"
+scst_dir="$(dirname "$scriptdir")"
 downloaddir=$HOME/software/downloads
 rpmbuild_dir=$HOME/rpmbuild
-if [ "$1" = "" ]; then
-  if echo "$(uname -r)" | grep -q uek; then
+
+if echo "$(uname -r)" | grep -q uek; then
     kernel="kernel-uek-$(uname -r)"
-  else
-    kernel="kernel-$(uname -r)"
-  fi
 else
-  kernel="$1"
+    kernel="kernel-$(uname -r)"
 fi
+
+releasever="$(sed -n -e 's/^.* release \([0-9.]*\).*$/\1/p' /etc/redhat-release)"
+distro="$(sed -n -e 's/^\(.*\) release .*$/\1/p' /etc/redhat-release)"
+
+install_prerequisites=true
+
+usage() {
+    echo "$(basename "$0") [-d <distro>] [-h] [-i] [-k <kver>] [-r <rel>]"
+}
+
+type /usr/bin/getopt >/dev/null || exit 1
+options="$(/usr/bin/getopt d:hik:r: "$@")" || { usage; exit 1; }
+set -- $options
+while [ "$1" != "${1#-}" ]; do
+    case "$1" in
+	'-d') distro="$2";     shift; shift;;
+	'-i') install_prerequisites="false"; shift;;
+        '-k') kernel="$2";     shift; shift;;
+	'-r') releasever="$2"; shift; shift;;
+        '--') shift; break;;
+        *)    usage; exit 1;;
+    esac
+done
+
 arch="$(uname -m)"
 kernel="${kernel%.${arch}}"
 kernel_src_rpm="${kernel}.src.rpm"
 kver="${kernel#kernel-}"
-distro="$(sed -n -e 's/^\(.*\) release .*$/\1/p' /etc/issue)"
-if [ -n "$2" ]; then
-  releasever="$2"
-else
-  releasever="$(sed -n -e 's/^.* release \([0-9.]*\).*$/\1/p' /etc/issue)"
-fi
-releasevermajor="$(echo $releasever | cut -f1 -d.)"
-releaseverminor="$(echo $releasever | cut -f2 -d.)"
-case "$distro" in
-  "CentOS"*)
-    case $releasever in
-      5.*|6.[01])
-        srpm_url=("http://vault.centos.org/${releasever}/os/SRPMS" "http://vault.centos.org/${releasever}/updates/SRPMS");;
-      *)
-        srpm_url=("http://vault.centos.org/${releasever}/os/Source/SPackages" "http://vault.centos.org/${releasever}/updates/Source/SPackages");;
-    esac
-    ;;
-  "Red Hat Enterprise Linux"*)
-    srpm_url=("http://ftp.redhat.com/pub/redhat/linux/enterprise/${releasevermajor}Server/en/os/SRPMS")
-    ;;
-  "Oracle Linux Server")
-    srpm_url=("http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/${releaseverminor}/base/x86_64/getPackageSource" "http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/latest/x86_64/getPackageSource" "http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/UEK/latest/x86_64/getPackageSource")
-    ;;
-  "Scientific Linux")
-    if [ "$releasevermajor" = 6 ]; then
-      srpm_url=("http://ftp.scientificlinux.org/linux/scientific/$releasever/SRPMS/vendor")
-    else
-      srpm_url=("http://ftp.scientificlinux.org/linux/scientific/$releasevermajor$releaseverminor/SRPMS/vendor")
-    fi
-    ;;
-  "Fedora")
-    srpm_url="http://ftp.redhat.com/redhat/rhel/rc/7/Server/source/tree/Packages"
-    ;;
-  *)
-    echo "Unknown type of distribution: $distro"
-    exit 1
-    ;;
-esac
+
+srpm_urls="$(get_srpm_urls "$distro" "$releasever" "$arch")" || exit $?
 
 function log {
     echo
@@ -100,6 +88,25 @@ function log {
     echo
 }
 
+copy_best_matching_patch() {
+    local f v
+
+    v="${kver}"
+    while [ "${v%[0-9a-z]}" != "$v" ]; do
+	f="${1}-${v}.patch"
+	if [ -e "$f" ]; then
+	    copy_patch "$f" "$2"
+	    return 0
+	fi
+	while [ "${v%[0-9a-z]}" != "$v" ]; do
+	    v="${v%[0-9a-z]}"
+	done
+	v="${v%.}"
+	v="${v%-}"
+    done
+    return 1
+}
+
 function copy_patch {
   local p="$1"
   while [ ! -e "$p" ]
@@ -137,7 +144,33 @@ fi
 
 log "Installing prerequisites"
 
-sudo yum install -y -q asciidoc binutils-devel elfutils-libelf-devel hmaccalc ncurses-devel newt-devel patchutils 'perl(ExtUtils::Embed)' python-devel redhat-rpm-config rpmdevtools rng-tools rpm-build unifdef xmlto yum-utils zlib-devel
+if $install_prerequisites; then
+    for p in \
+asciidoc \
+audit-libs-devel \
+binutils-devel \
+elfutils-devel \
+elfutils-libelf-devel \
+hmaccalc \
+ncurses-devel \
+newt-devel \
+patchutils \
+numactl-devel \
+pciutils-devel \
+'perl(ExtUtils::Embed)' \
+pesign \
+python-devel \
+redhat-rpm-config \
+rng-tools \
+rpm-build \
+rpmdevtools \
+unifdef \
+wget \
+xmlto \
+yum-utils \
+zlib-devel \
+; do sudo yum install -y -q "$p"; done
+fi
 
 rc=$?; if [ $rc != 0 ]; then exit $rc; fi
 
@@ -150,7 +183,7 @@ log "Installing, unpacking and preparing kernel source files"
 mkdir -p ${downloaddir}
 if [ ! -e ${downloaddir}/${kernel_src_rpm} ]; then
   cd ${downloaddir}
-  for dir in ${srpm_url[@]}
+  for dir in ${srpm_urls}
   do
     url="$dir/${kernel_src_rpm}"
     echo "Trying $url ..."
@@ -166,7 +199,9 @@ fi
 
 log "Installing kernel build prerequisites"
 
-sudo yum-builddep -q -y ${downloaddir}/${kernel_src_rpm}
+if $install_prerequisites; then
+    sudo yum-builddep -q -y ${downloaddir}/${kernel_src_rpm}
+fi
 
 log "Installing kernel sources in ${rpmbuild_dir}"
 
@@ -185,11 +220,16 @@ cd SPECS
 log "Copying SCST patches to the SOURCES directory"
 
 cd ${rpmbuild_dir}/SOURCES
-copy_patch $scst_dir/scst/kernel/rhel/scst_exec_req_fifo-${kver}.patch scst_exec_req_fifo.patch
-f="$scst_dir/iscsi-scst/kernel/patches/rhel/put_page_callback-${kver}.patch"
-if [ -e "$f" ]; then
-    copy_patch "$f" put_page_callback.patch
-fi
+copy_best_matching_patch $scst_dir/scst/kernel/rhel/scst_exec_req_fifo scst_exec_req_fifo.patch ||
+{
+    echo "No matching scst_exec_req_fifo patch found for kernel version $kver";
+    exit 1;
+}
+copy_best_matching_patch $scst_dir/iscsi-scst/kernel/patches/rhel/put_page_callback put_page_callback.patch ||
+{
+    echo "No matching scst_exec_req_fifo patch found for kernel version $kver";
+    exit 1;
+}
 
 log "Adding SCST patches in kernel.spec"
 
@@ -325,7 +365,7 @@ diff -u SPECS/kernel.spec{.orig,}
    make ARCH=$Arch %{oldconfig_target} > /dev/null
    echo "# $Arch" > configs/$i
 EOF
-elif [ ${kver#3.10.0-121} != $kver ]; then
+elif [ ${kver#3.10.0-12[13]} != $kver ]; then
 # RHEL/CentOS/SL 7.0
 patch -p1 ${rpmbuild_dir}/SPECS/kernel.spec <<'EOF' || exit $?
 --- kernel.spec.orig	2014-05-23 10:09:17.707202148 +0200
@@ -343,7 +383,7 @@ patch -p1 ${rpmbuild_dir}/SPECS/kernel.spec <<'EOF' || exit $?
  Source2001: cpupower.config
  
 +Patch200: scst_exec_req_fifo.patch
-+#Patch201: put_page_callback.patch
++Patch201: put_page_callback.patch
 +
  # empty final patch to facilitate testing of kernel patches
  Patch999999: linux-kernel-test.patch
@@ -353,7 +393,7 @@ patch -p1 ${rpmbuild_dir}/SPECS/kernel.spec <<'EOF' || exit $?
  cp $RPM_SOURCE_DIR/kernel-%{version}-*.config .
  
 +ApplyPatch scst_exec_req_fifo.patch
-+#ApplyPatch put_page_callback.patch
++ApplyPatch put_page_callback.patch
 +
  ApplyOptionalPatch linux-kernel-test.patch
  
diff --git a/scripts/rhel-rpm-functions b/scripts/rhel-rpm-functions
new file mode 100644
index 000000000..a6765ae3f
--- /dev/null
+++ b/scripts/rhel-rpm-functions
@@ -0,0 +1,98 @@
+# -*- mode: shell-script -*-
+# Shell functions for downloading and extracting a RHEL or RHEL clone RPM
+
+# Arguments:
+# $1: Linux distribution name
+# $2: Linux distribution version (major.minor)
+# $3: architecture
+function get_srpm_urls() {
+    local arch distro releasever releasevermajor releaseverminor
+
+    distro="$1"
+    releasever="$2"
+    arch="$3"
+    IFS=.
+    set -- "$2"
+    unset IFS
+    releasevermajor="$1"
+    releaseverminor="$2"
+
+    case "$distro" in
+	"CentOS"*)
+	    case $releasever in
+		5.*|6.[01])
+		    echo "http://vault.centos.org/${releasever}/os/SRPMS http://vault.centos.org/${releasever}/updates/SRPMS";;
+		[67].*)
+		    echo "http://vault.centos.org/${releasever}/os/Source/SPackages http://vault.centos.org/${releasever}/updates/Source/SPackages";;
+	    esac
+	    ;;
+	"Red Hat Enterprise Linux"*)
+	    case $releasever in
+		[56].*)
+		    echo "http://ftp.redhat.com/pub/redhat/linux/enterprise/${releasevermajor}Server/en/os/SRPMS http://ftp.redhat.com/redhat/rhel/rc/7/Server/source/tree/Packages";;
+	    esac
+	    ;;
+	"Oracle Linux Server")
+	    echo "http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/${releaseverminor}/base/${arch}/getPackageSource http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/latest/${arch}/getPackageSource http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/UEK/latest/${arch}/getPackageSource"
+	    ;;
+	"Scientific Linux")
+	    case $releasever in
+		5.*)
+		    echo "http://ftp.scientificlinux.org/linux/scientific/$releasevermajor$releaseverminor/SRPMS/vendor";;
+		6.*)
+		    echo "http://ftp.scientificlinux.org/linux/scientific/$releasever/SRPMS/vendor";;
+	    esac
+	    ;;
+	*)
+	    echo "Unknown type of distribution: $distro" >&2
+	    return 1
+	    ;;
+    esac
+}
+
+# Arguments:
+# $1: Linux distribution name
+# $2: Linux distribution version (major.minor)
+# $3: architecture
+function get_rpm_urls() {
+    local arch distro releasever releasevermajor releaseverminor
+
+    distro="$1"
+    releasever="$2"
+    arch="$3"
+    IFS=.
+    set -- "$2"
+    unset IFS
+    releasevermajor="$1"
+    releaseverminor="$2"
+
+    case "$distro" in
+	"CentOS"*)
+	    case $releasever in
+		5.*)
+		    echo "http://vault.centos.org/${releasever}/os/${arch}/CentOS http://vault.centos.org/${releasever}/updates/${arch}/RPMS";;
+		6.[01])
+		    echo "http://vault.centos.org/${releasever}/os/${arch}/Packages http://vault.centos.org/${releasever}/updates/${arch}/Packages";;
+		[67].*)
+		    echo "http://vault.centos.org/${releasever}/os/${arch}/Packages http://vault.centos.org/${releasever}/updates/${arch}/Packages";;
+	    esac
+	    ;;
+	"Red Hat Enterprise Linux"*)
+	    echo "";;
+	"Oracle Linux Server")
+	    echo "http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/${releaseverminor}/base/${arch}/getPackageSource http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/latest/${arch}/getPackageSource http://public-yum.oracle.com/repo/OracleLinux/OL${releasevermajor}/UEK/latest/${arch}/getPackageSource"
+	    ;;
+	"Scientific Linux")
+	    case $releasever in
+		5.*)
+		    echo "http://ftp.scientificlinux.org/linux/scientific/$releasevermajor$releaseverminor/SRPMS/vendor";;
+		6.*)
+		    echo "http://ftp.scientificlinux.org/linux/scientific/$releasever/SRPMS/vendor";;
+	    esac
+	    ;;
+	*)
+	    echo "Unknown distribution type: $distro" >&2
+	    return 1
+	    ;;
+    esac
+}
diff --git a/scripts/run-regression-tests b/scripts/run-regression-tests
index 65105cf9d..f792254c4 100755
--- a/scripts/run-regression-tests
+++ b/scripts/run-regression-tests
@@ -263,30 +263,32 @@ CONFIG_TRACING CONFIG_X86_32                    \
 "
 
   echo "Patching and configuring kernel ..."
+  if [ "$ipv6" = "false" ]; then
+      disable="$disable CONFIG_IPV6"
+  fi
   (
     local srcdir="$PWD"
-    cd "${outputdir}/linux-$1"                                      \
-    && if [ "${multiple_patches}" = "false" ]; then
-         patch -p1 -f -s <"${patchfile}" >"${patchoutput}"
-       else
-         rm -f "${patchoutput}"
-         for p in "${outputdir}/${patchdir}"/*
-         do
-           echo "==== $p" >>"${patchoutput}"
-           patch -p1 -f -s <"${p}" >>"${patchoutput}" 2>&1
-         done
-       fi \
-    && if [ -e $srcdir/srpt/patches/kernel-${kver}-pre-cflags.patch ]; then 
-         echo "$srcdir/srpt/patches/kernel-${kver}-pre-cflags.patch ..." \
+    cd "${outputdir}/linux-$1" &&
+    if [ "${multiple_patches}" = "false" ]; then
+        patch -p1 -f -s <"${patchfile}" >"${patchoutput}"
+    else
+        rm -f "${patchoutput}"
+        for p in "${outputdir}/${patchdir}"/*; do
+            echo "==== $p" >>"${patchoutput}"
+            patch -p1 -f -s <"${p}" >>"${patchoutput}" 2>&1
+        done
+    fi &&
+    if [ -e $srcdir/srpt/patches/kernel-${kver}-pre-cflags.patch ]; then
+        echo "$srcdir/srpt/patches/kernel-${kver}-pre-cflags.patch ..." \
            >>"${patchoutput}"
-         patch -p1 -f -s <$srcdir/srpt/patches/kernel-${kver}-pre-cflags.patch \
-	   >>"${patchoutput}";
-       else
-         echo "srpt/patches/kernel-${kver}-pre-cflags.patch not found."; \
-       fi \
-    && make -s allmodconfig &>"${outputdir}/make-config-output.txt" \
-    && for c in $disable; do sed -i.tmp "s/^$c=y\$/$c=n/" .config; done \
-    && make -s oldconfig &>/dev/null 
+        patch -p1 -f -s <$srcdir/srpt/patches/kernel-${kver}-pre-cflags.patch \
+	   >>"${patchoutput}"
+    else
+        echo "srpt/patches/kernel-${kver}-pre-cflags.patch not found."
+    fi &&
+    make -s allmodconfig &>"${outputdir}/make-config-output.txt" &&
+    for c in $disable; do sed -i.tmp "s/^$c=[ym]\$/$c=n/" .config; done &&
+    make -s oldconfig &>/dev/null
   )
 }
 
@@ -585,6 +587,7 @@ do
   run_checkpatch="true"
   run_sparse="true"
   run_smatch="true"
+  ipv6="true"
   global_multiple_patches="${multiple_patches}"
   while [ "${kv%-?}" != "${kv}" -o "${kv%-??}" != "${kv}" ]; do
     kv_without_opt="${kv%-?}"
@@ -593,6 +596,7 @@ do
     fi
     kopt="${kv#${kv_without_opt}}"
     case "${kopt}" in
+      '-4')  ipv6="false";;
       '-f')  full_check="true";;
       '-i')  ibmvio="true";;
       '-nc') run_checkpatch="false";;
diff --git a/scst/src/scst_mem.c b/scst/src/scst_mem.c
index ea099a727..7bc6b4418 100644
--- a/scst/src/scst_mem.c
+++ b/scst/src/scst_mem.c
@@ -1021,7 +1021,13 @@ struct scatterlist *sgv_pool_alloc(struct sgv_pool *pool, unsigned int size,
 				goto out_fail_free;
 		}
 
-		TRACE_MEM("Brand new obj %p", obj);
+		if (likely(!obj->recycling_list_entry.next)) {
+			TRACE_MEM("Brand new obj %p", obj);
+		} else if (unlikely(obj->sg_entries != obj->sg_entries_data)) {
+			TRACE_MEM("Cached obj %p with sg_count == 0", obj);
+			kfree(obj->sg_entries);
+			obj->sg_entries = NULL;
+		}
 
 		if (pages_to_alloc <= sgv_max_local_pages) {
 			obj->sg_entries = obj->sg_entries_data;