config/kernel-misc-minor.m4

   1 dnl #
   2 dnl # Determine an available miscellaneous minor number which can be used
   3 dnl # for the /dev/zfs device.  This is needed because kernel module
   4 dnl # auto-loading depends on registering a reserved non-conflicting minor
   5 dnl # number.  Start with a large known available unreserved minor and work
   6 dnl # our way down to lower value if a collision is detected.
   7 dnl #
   8 AC_DEFUN([ZFS_AC_KERNEL_MISC_MINOR], [
   9         AC_MSG_CHECKING([for available /dev/zfs minor])
  10
  11         for i in $(seq 249 -1 200); do
  12                 if ! grep -q "^#define\s\+.*_MINOR\s\+.*$i" \
  13                     ${LINUX}/include/linux/miscdevice.h; then
  14                         ZFS_DEVICE_MINOR="$i"
  15                         AC_MSG_RESULT($ZFS_DEVICE_MINOR)
  16                         AC_DEFINE_UNQUOTED([ZFS_DEVICE_MINOR],
  17                             [$ZFS_DEVICE_MINOR], [/dev/zfs minor])
  18                         break
  19                 fi
  20         done
  21
  22         AS_IF([ test -z "$ZFS_DEVICE_MINOR"], [
  23                 AC_MSG_ERROR([
  24         *** No available misc minor numbers available for use.])
  25         ])
  26 ])