android_kernel_samsung_msm8976/init/Makefile
Will Drewry bad6663f24 CHROMIUM: dm: boot time specification of dm=
This is a wrap-up of three patches pending upstream approval.
I'm bundling them because they are interdependent, and it'll be
easier to drop it on rebase later.

1. dm: allow a dm-fs-style device to be shared via dm-ioctl

Integrates feedback from Alisdair, Mike, and Kiyoshi.

Two main changes occur here:

- One function is added which allows for a programmatically created
mapped device to be inserted into the dm-ioctl hash table.  This binds
the device to a name and, optional, uuid which is needed by udev and
allows for userspace management of the mapped device.

- dm_table_complete() was extended to handle all of the final
functional changes required for the table to be operational once
called.

2. init: boot to device-mapper targets without an initr*

Add a dm= kernel parameter modeled after the md= parameter from
do_mounts_md.  It allows for device-mapper targets to be configured at
boot time for use early in the boot process (as the root device or
otherwise).  It also replaces /dev/XXX calls with major:minor opportunistically.

The format is dm="name uuid ro,table line 1,table line 2,...".  The
parser expects the comma to be safe to use as a newline substitute but,
otherwise, uses the normal separator of space.  Some attempt has been
made to make it forgiving of additional spaces (using skip_spaces()).

A mapped device created during boot will be assigned a minor of 0 and
may be access via /dev/dm-0.

An example dm-linear root with no uuid may look like:

root=/dev/dm-0  dm="lroot none ro, 0 4096 linear /dev/ubdb 0, 4096 4096 linear /dv/ubdc 0"

Once udev is started, /dev/dm-0 will become /dev/mapper/lroot.

Older upstream threads:
http://marc.info/?l=dm-devel&m=127429492521964&w=2
http://marc.info/?l=dm-devel&m=127429499422096&w=2
http://marc.info/?l=dm-devel&m=127429493922000&w=2

Latest upstream threads:
https://patchwork.kernel.org/patch/104859/
https://patchwork.kernel.org/patch/104860/
https://patchwork.kernel.org/patch/104861/

BUG: 27175947

Signed-off-by: Will Drewry <wad@chromium.org>
Review URL: http://codereview.chromium.org/2020011
Change-Id: I92bd53432a11241228d2e5ac89a3b20d19b05a31
2016-05-18 14:36:11 +05:30

34 lines
1.1 KiB
Makefile

#
# Makefile for the linux kernel.
#
obj-y := main.o version.o mounts.o
obj-y += noinitramfs.o
obj-$(CONFIG_BLK_DEV_INITRD) += initramfs.o
obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
ifneq ($(CONFIG_ARCH_INIT_TASK),y)
obj-y += init_task.o
endif
mounts-y := do_mounts.o
mounts-$(CONFIG_BLK_DEV_RAM) += do_mounts_rd.o
mounts-$(CONFIG_BLK_DEV_INITRD) += do_mounts_initrd.o
mounts-$(CONFIG_BLK_DEV_MD) += do_mounts_md.o
mounts-$(CONFIG_BLK_DEV_DM) += do_mounts_dm.o
# dependencies on generated files need to be listed explicitly
$(obj)/version.o: include/generated/compile.h
# compile.h changes depending on hostname, generation number, etc,
# so we regenerate it always.
# mkcompile_h will make sure to only update the
# actual file if its content has changed.
chk_compile.h = :
quiet_chk_compile.h = echo ' CHK $@'
silent_chk_compile.h = :
include/generated/compile.h: FORCE
@$($(quiet)chk_compile.h)
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CC) $(KBUILD_CFLAGS)"