document kernel command-line parameters

hooks/lvm/lvm

@@ -3,9 +3,6 @@
 #
 # false positive
 # shellcheck disable=2154
-#
-# word splitting is safe by design
-# shellcheck disable=2086
 {
     [ "$hostonly" = 1 ] &&
         for _module in \
@@ -29,17 +26,10 @@
             use_lvmetad = 0
         }"
 
-    IFS=,; set -- $lvm_opts; unset IFS
-
-    for opt; do case "$opt" in
-        config=1) embed_lvm_config=
-    esac; done
-
     mkdir -p "${tmpdir}/etc/lvm"
 
     lvm config \
         --config "$lvm_config" \
-        ${embed_lvm_config+--mergedconfig} \
+        ${lvm_config:+--mergedconfig} \
     > "${tmpdir}/etc/lvm/lvm.conf"
 }
-

hooks/lvm/lvm.init

@@ -5,35 +5,22 @@
 # shellcheck disable=2154
 #
 # word splitting is safe by design
-# shellcheck disable=2086,2068
+# shellcheck disable=2068
 {
     [ "$break" = lvm ] && { print "break before trigger_lvm()"; sh; }
 
+    export DM_DISABLE_UDEV=1
     mkdir -p /run/lvm /run/lock/lvm
 
-    IFS=,; set -- $lvm_opts; unset IFS
-
-    for opt; do case "$opt" in
-        discard=1) lvm_discard="--config=devices{issue_discards=1}" ;;
-        config=0)  : > /etc/lvm/lvm.conf ;;
-        group=*)   lvm_group="${opt#*=}" ;;
-        name=*)    lvm_name="/${opt#*=}" ;;
-        tag=*)     lvm_tag="@${opt#*=}"  ;;
-    esac; done
-
-    set -- "--sysinit" "-qq" "-aay" "$lvm_discard"
-
-    # libdevice-mapper assumes that udev have dm rules
-    # which is not true because we use our device-helper for dm stuff
-    # this variable fixes possible(?) hang
-    export DM_DISABLE_UDEV=1
+    set -- \
+        --sysinit -qq -aay "${lvm_discard:+--config=devices{issue_discards=1}}"
 
     if [ "$lvm_group" ] && [ "$lvm_name" ]; then
-        lvm lvchange $@ "${lvm_group}${lvm_name}"
+        lvm lvchange $@ "${lvm_group}/${lvm_name}"
     elif [ "$lvm_group" ]; then
         lvm vgchange $@ "$lvm_group"
     elif [ "$lvm_tag" ]; then
-        lvm lvchange $@ "$lvm_tag"
+        lvm lvchange $@ "@${lvm_tag}"
     else
         lvm vgchange $@
     fi || panic "failed to trigger LVM"