ubi: fastmap: Add control in 'UBI_IOCATT' ioctl to reserve PEBs for filling pools

This patch imports a new field 'need_resv_pool' in struct 'ubi_attach_req'
to control whether or not reserving free PEBs for filling pool/wl_pool.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217787
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi: fastmap: Add fastmap control support for 'UBI_IOCATT' ioctl

[1] suggests that fastmap is suitable for large flash devices. Module
parameter 'fm_autoconvert' is a coarse grained switch to enable all
ubi devices to generate fastmap, which may turn on fastmap even for
small flash devices.

This patch imports a new field 'disable_fm' in struct 'ubi_attach_req'
to support following situations by ioctl 'UBI_IOCATT'.
[old functions]
A. Disable 'fm_autoconvert': Disbable fastmap for all ubi devices
B. Enable 'fm_autoconvert': Enable fastmap for all ubi devices
[new function]
C. Enable 'fm_autoconvert', set 'disable_fm' for given device: Don't
create new fastmap and do full scan (existed fastmap will be
destroyed) for the given ubi device.

A simple test case in [2].

[1] http://www.linux-mtd.infradead.org/doc/ubi.html#L_fastmap
[2] https://bugzilla.kernel.org/show_bug.cgi?id=216278

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi: Expose the bitrot interface

Using UBI_IOCRPEB and UBI_IOCSPEB userspace can force
reading and scrubbing of PEBs.

In case of bitflips UBI will automatically take action
and move data to a different PEB.
This interface allows a daemon to foster your NAND.

Signed-off-by: Richard Weinberger <richard@nod.at>

ubi: expose the volume CRC check skip flag

Now that we have the logic for skipping CRC check for static UBI volumes
in the core, let's expose it to users.

This makes use of a padding byte in the volume description data
structure as a flag. This flag only tell for now whether we should skip
the CRC check of a volume.

This checks the UBI volume for which we are trying to skip the CRC check
is static.

Let's also make sure that the flags passed to verify_mkvol_req are
valid.

We voluntarily do not take into account the skip_check flag in
vol_cdev_write() as we want to make sure what we wrote was correctly
written.

Suggested-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

License cleanup: add SPDX license identifier to uapi header files with a license

Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be. This makes it hard for
compliance tools to determine the correct license.

Update these files with an SPDX license identifier. The identifier was
chosen based on the license information in the file.

GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:

NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".

This exception makes it possible to include GPL headers into non GPL
code, without confusing license compliance tools.

Headers which have either explicit dual licensing or are just licensed
under a non GPL license are updated with the corresponding SPDX
identifier and the GPLv2 with syscall exception identifier. The format
is:
((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)

SPDX license identifiers are a legally binding shorthand, which can be
used instead of the full boiler plate text. The update does not remove
existing license information as this has to be done on a case by case
basis and the copyright holders might have to be consulted. This will
happen in a separate step.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

UBI: make UBI_IOCVOLCRBLK take a parameter for future usage

In order to allow a future ioctl parameter, such as a creation flag,
we change the UBI_IOCVOLCRBLK so it accepts a struct ubi_blkcreate_req.
For the time being the structure is not in use, but fully reserved.

This ABI change is still possible and harmless, because the ioctl has just
been introduced and there's no userspace program which uses it.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: rename block device ioctls

Rename the UBI_IOCVOLATTBLK and UBI_IOCVOLDETBLK to UBI_IOCVOLCRBLK and
UBI_IOCVOLRMBLK, because we do not use terms "attach" and "detach" for the R/O
block devices on top of UBI volumes. Instead, we use terms "create" and
"remove". This patch also amends the related commentaries.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>

UBI: R/O block driver on top of UBI volumes

This commit introduces read-only block device emulation on top of UBI volumes.

Given UBI takes care of wear leveling and bad block management it's possible
to add a thin layer to enable block device access to UBI volumes.
This allows to use a block-oriented filesystem on a flash device.

The UBI block devices are meant to be used in conjunction with any
regular, block-oriented file system (e.g. ext4), although it's primarily
targeted at read-only file systems, such as squashfs.

Block devices are created upon user request through new ioctls:
UBI_IOCVOLATTBLK to attach and UBI_IOCVOLDETBLK to detach.
Also, a new UBI module parameter is added 'ubi.block'. This parameter is
needed in order to attach a block device on boot-up time, allowing to
mount the rootfs on a ubiblock device.
For instance, you could have these kernel parameters:

ubi.mtd=5 ubi.block=0,0 root=/dev/ubiblock0_0

Or, if you compile ubi as a module:

$ modprobe ubi mtd=/dev/mtd5 block=/dev/ubi0_0

Artem: amend commentaries and massage the patch a little bit.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: document UBI_IOCVOLUP better in user header

The current ioctl define implies that this func expects to be passed a
64bit number directly rather than a pointer to a 64bit. The code that
processes this ioctl shows that it clearly expects a pointer.

It'd be best if we could change the type to "__s64*", but that would
change the generated ioctl number thus breaking the userland ABI. So
just add a comment for intrepid developers.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UAPI: (Scripted) Disintegrate include/mtd

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>