driver core: clean up the logic to determine which /sys/dev/ directory to use

When a dev_t is set in a struct device, an symlink in /sys/dev/ is
created for it either under /sys/dev/block/ or /sys/dev/char/ depending
on the device type.

The logic to determine this would trigger off of the class of the
object, and the kobj_type set in that location. But it turns out that
this deep nesting isn't needed at all, as it's either a choice of block
or "everything else" which is a char device. So make the logic a lot
more simple and obvious, and remove the incorrect comments in the code
that tried to document something that was not happening at all (it is
impossible to set class->dev_kobj to NULL as the class core prevented
that from happening.

This removes the only place that class->dev_kobj was being used, so
after this, it can be removed entirely.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "devtmpfs: add debug info to handle()"

This reverts commit 90a9d5ff225267b3376f73c19f21174e3b6d7746 as it is
reported to cause boot regressions.

Link: https://lore.kernel.org/r/Y+rSXg14z1Myd8Px@dev-arch.thelio-3990X
Reported-by: Nathan Chancellor <nathan@kernel.org>
Cc: Longlong Xia <xialonglong1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "devtmpfs: remove return value of devtmpfs_delete_node()"

This reverts commit 9d3fe6aa6b9517408064c7c3134187e8ec77dbf7 as it is
reported to cause boot regressions.

Link: https://lore.kernel.org/r/Y+rSXg14z1Myd8Px@dev-arch.thelio-3990X
Reported-by: Nathan Chancellor <nathan@kernel.org>
Cc: Longlong Xia <xialonglong1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: remove return value of devtmpfs_delete_node()

The only caller of device_del() does not check the return value. And
there's nothing we can do when cleaning things up on a remove path.
Let's make it a void function.

Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Link: https://lore.kernel.org/r/20230210095444.4067307-4-xialonglong1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: add debug info to handle()

Because handle() is the core function for processing devtmpfs requests,
Let's add some debug info in handle() to help users know why failed.

Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Link: https://lore.kernel.org/r/20230210095444.4067307-3-xialonglong1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: convert to pr_fmt

Use the pr_fmt() macro to prefix all the output with "devtmpfs: ".
while at it, convert printk(<LEVEL>) to pr_<level>().

Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Link: https://lore.kernel.org/r/20230202033203.1239239-2-xialonglong1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs: port vfs_*() helpers to struct mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

devtmpfs: fix the dangling pointer of global devtmpfsd thread

When the devtmpfs fails to mount, a dangling pointer still remains in
global. Specifically, the err variable is passed by a pointer to the
devtmpfsd. When the devtmpfsd exits, it sets the error and completes the
setup_done. In this situation, the thread pointer is not set to null.
After the devtmpfsd exited, the devtmpfs can wakes up the destroyed
devtmpfsd thread by wake_up_process if a device change event comes.

Signed-off-by: Yangxi Xiang <xyangxi5@gmail.com>
Link: https://lore.kernel.org/r/20220627120409.11174-1-xyangxi5@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: drop redundant fs parameters from internal fs

The internal_fs_type is mounted via vfs_kernel_mount() and is never
registered as a filesystem, thus specifying the parameters is redundant
as those params will not be validated by fs_validate_description().

Both {shmem,ramfs}_fs_parameters are anyway validated when those
respective filesystems are first registered, so there is no reason to
pass them to devtmpfs too, drop them.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
Link: https://lore.kernel.org/r/20220119220248.32225-1-ailiop@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

block: remove genhd.h

There is no good reason to keep genhd.h separate from the main blkdev.h
header that includes it. So fold the contents of genhd.h into blkdev.h
and remove genhd.h entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220124093913.742411-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

devtmpfs regression fix: reconfigure on each mount

Prior to Linux v5.4 devtmpfs used mount_single() which treats the given
mount options as "remount" options, so it updates the configuration of
the single super_block on each mount.

Since that was changed, the mount options used for devtmpfs are ignored.
This is a regression which affect systemd - which mounts devtmpfs with
"-o mode=755,size=4m,nr_inodes=1m".

This patch restores the "remount" effect by calling reconfigure_single()

Fixes: d401727ea0d7 ("devtmpfs: don't mix {ramfs,shmem}_fill_super() with mount_single()")
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

devtmpfs: mount with noexec and nosuid

devtmpfs is writable. Add the noexec and nosuid as default mount flags
to prevent code execution from /dev. The systems who don't use systemd
and who rely on CONFIG_DEVTMPFS_MOUNT=y are the ones to be protected by
this patch. Other systems are fine with the udev solution.

No sane program should be relying on executing from /dev. So this patch
reduces the attack surface. It doesn't prevent any specific attack, but
it reduces the possibility that someone can use /dev as a place to put
executable code. Chrome OS has been carrying this patch for several
years. It seems trivial and simple solution to improve the protection of
/dev when CONFIG_DEVTMPFS_MOUNT=y.

Original patch:
https://lore.kernel.org/lkml/20121120215059.GA1859@www.outflux.net/

Cc: ellyjones@chromium.org
Cc: Kay Sievers <kay@vrfy.org>
Cc: Roland Eggner <edvx1@systemanalysen.net>
Co-developed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/YcMfDOyrg647RCmd@debian-BULLSEYE-live-builder-AMD64
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: actually reclaim some init memory

Currently gcc seems to inline devtmpfs_setup() into devtmpfsd(), so
its memory footprint isn't reclaimed as intended. Mark it noinline to
make sure it gets put in .init.text.

While here, setup_done can also be put in .init.data: After complete()
releases the internal spinlock, the completion object is never touched
again by that thread, and the waiting thread doesn't proceed until it
observes ->done while holding that spinlock.

This is now the same pattern as for kthreadd_done in init/main.c:
complete() is done in a __ref function, while the corresponding
wait_for_completion() is in an __init function.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20210312103027.2701413-2-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: fix placement of complete() call

Calling complete() from within the __init function is wrong -
theoretically, the init process could proceed all the way to freeing
the init mem before the devtmpfsd thread gets to execute the return
instruction in devtmpfs_setup().

In practice, it seems to be harmless as gcc inlines devtmpfs_setup()
into devtmpfsd(). So the calls of the __init functions init_chdir()
etc. actually happen from devtmpfs_setup(), but the __ref on that one
silences modpost (it's all right, because those calls happen before
the complete()). But it does make the __init annotation of the setup
function moot, which we'll fix in a subsequent patch.

Fixes: bcbacc4909f1 ("devtmpfs: refactor devtmpfsd()")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20210312103027.2701413-1-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

namei: prepare for idmapped mounts

The various vfs_*() helpers are called by filesystems or by the vfs
itself to perform core operations such as create, link, mkdir, mknod, rename,
rmdir, tmpfile and unlink. Enable them to handle idmapped mounts. If the
inode is accessed through an idmapped mount map it into the
mount's user namespace and pass it down. Afterwards the checks and
operations are identical to non-idmapped mounts. If the initial user
namespace is passed nothing changes so non-idmapped mounts will see
identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-15-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

init: add an init_chroot helper

Add a simple helper to chroot with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_chroot.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_chdir helper

Add a simple helper to chdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_chdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_mount helper

Like do_mount, but takes a kernel pointer for the destination path.
Switch over the mounts in the init code and devtmpfs to it, which
just happen to work due to the implicit set_fs(KERNEL_DS) during early
init right now.

Signed-off-by: Christoph Hellwig <hch@lst.de>

devtmpfs: refactor devtmpfsd()

Split the main worker loop into a separate function. This allows
devtmpfsd_setup to be marked __init, which will allows us to call
__init routines for the setup work. devtmpfѕ itself needs a __ref
marker for that to work, and a comment explaining why it works.

Signed-off-by: Christoph Hellwig <hch@lst.de>

fs_parse: fold fs_parameter_desc/fs_parameter_spec

The former contains nothing but a pointer to an array of the latter...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

devtmpfs: factor out common tail of devtmpfs_{create,delete}_node

There's some common boilerplate in devtmpfs_{create,delete}_node, put
that in a little helper.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20200115184154.3492-6-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: initify a bit

devtmpfs_mount() is only called from prepare_namespace() in
init/do_mounts.c, which is an __init function, so devtmpfs_mount() can
also be moved to .init.text.

Then the mount_dev static variable is only referenced from __init
functions (devtmpfs_mount and its initializer function mount_param).

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20200115184154.3492-5-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: simplify initialization of mount_dev

Avoid a bit of ifdeffery by using the IS_ENABLED() helper.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20200115184154.3492-4-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: factor out setup part of devtmpfsd()

Factor out the setup part of devtmpfsd() to make it a bit easier to
see that we always call setup_done() exactly once (provided of course
the kthread is succesfully created).

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20200115184154.3492-3-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: fix theoretical stale pointer deref in devtmpfsd()

After complete(&setup_done), devtmpfs_init proceeds and may actually
return, invalidating the *err pointer, before devtmpfsd() proceeds to
reading back *err.

This is of course completely theoretical since the error conditions
never trigger in practice, and even if they did, nobody cares about
the exit value from a kernel thread, so it doesn't matter if we happen
to read back some garbage from some other stack frame. Still, this
isn't a pattern that should be copy-pasted, so fix it.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20200115184154.3492-2-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: use do_mount() instead of ksys_mount()

In devtmpfs, do_mount() can be called directly instead of complex wrapping
by ksys_mount():
- the first and third arguments are const strings in the kernel,
and do not need to be copied over from userspace;
- the fifth argument is NULL, and therefore no page needs to be
copied over from userspace;
- the second and fourth argument are passed through anyway.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API

Convert the ramfs, shmem, tmpfs, devtmpfs and rootfs filesystems to the new
internal mount API as the old one will be obsoleted and removed. This
allows greater flexibility in communication of mount parameters between
userspace, the VFS and the filesystem.

See Documentation/filesystems/mount_api.txt for more information.

Note that tmpfs is slightly tricky as it can contain embedded commas, so it
can't be trivially split up using strsep() to break on commas in
generic_parse_monolithic(). Instead, tmpfs has to supply its own generic
parser.

However, if tmpfs changes, then devtmpfs and rootfs, which are wrappers
around tmpfs or ramfs, must change too - and thus so must ramfs, so these
had to be converted also.

[AV: rewritten]

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hugh Dickins <hughd@google.com>
cc: linux-mm@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

make shmem_fill_super() static

... have callers use shmem_mount()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

devtmpfs: don't mix {ramfs,shmem}_fill_super() with mount_single()

Create an internal-only type matching the current devtmpfs, never
register it and have one kernel-internal mount done. That thing
gets mounted only once, so it is free to use mount_nodev().

The "public" devtmpfs (the one we do register, and only after
the internal mount of the real thing is done) simply gets and
returns an extra reference to the internal superblock.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

constify ksys_mount() string arguments

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

vfs: Suppress MS_* flag defs within the kernel unless explicitly enabled

Only the mount namespace code that implements mount(2) should be using the
MS_* flags. Suppress them inside the kernel unless uapi/linux/mount.h is
included.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: David Howells <dhowells@redhat.com>

drivers/base/devtmpfs.c: don't pretend path is const in delete_path

path is the result of kstrdup, and we repeatedly call strrchr on it,
modifying it through the returned pointer. So there's no reason to
pretend path is const.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare()

Using this helper allows us to avoid the in-kernel calls to the
sys_unshare() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the same
calling convention as sys_unshare().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

fs: add ksys_chdir() helper; remove in-kernel calls to sys_chdir()

Using this helper allows us to avoid the in-kernel calls to the sys_chdir()
syscall. The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_chdir().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

fs: add ksys_chroot() helper; remove-in kernel calls to sys_chroot()

Using this helper allows us to avoid the in-kernel calls to the
sys_chroot() syscall. The ksys_ prefix denotes that this function is
meant as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_chroot().

In the near future, the fs-external callers of ksys_chroot() should be
converted to use kern_path()/set_fs_root() directly. Then ksys_chroot()
can be moved within sys_chroot() again.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

fs: add ksys_mount() helper; remove in-kernel calls to sys_mount()

Using this helper allows us to avoid the in-kernel calls to the sys_mount()
syscall. The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_mount().

In the near future, all callers of ksys_mount() should be converted to call
do_mount() directly.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

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>

statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

wrappers for ->i_mutex access

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

VFS: assorted weird filesystems: d_inode() annotations

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

devtmpfs: Calling delete_path() only when necessary

The deleted variable is always 1 in current code.
Initialize deleted variable to be 0, so delete_path() will be called only when
necessary.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

locks: break delegations on any attribute modification

NFSv4 uses leases to guarantee that clients can cache metadata as well
as data.

Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: David Howells <dhowells@redhat.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

locks: break delegations on unlink

We need to break delegations on any operation that changes the set of
links pointing to an inode. Start with unlink.

Such operations also hold the i_mutex on a parent directory. Breaking a
delegation may require waiting for a timeout (by default 90 seconds) in
the case of a unresponsive NFS client. To avoid blocking all directory
operations, we therefore drop locks before waiting for the delegation.
The logic then looks like:

acquire locks
...
test for delegation; if found:
take reference on inode
release locks
wait for delegation break
drop reference on inode
retry

It is possible this could never terminate. (Even if we take precautions
to prevent another delegation being acquired on the same inode, we could
get a different inode on each retry.) But this seems very unlikely.

The initial test for a delegation happens after the lock on the target
inode is acquired, but the directory inode may have been acquired
further up the call stack. We therefore add a "struct inode **"
argument to any intervening functions, which we use to pass the inode
back up to the caller in the case it needs a delegation synchronously
broken.

Cc: David Howells <dhowells@redhat.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

driver core: handle user namespaces properly with the uid/gid devtmpfs change

Now that devtmpfs is caring about uid/gid, we need to use the correct
internal types so users who have USER_NS enabled will have things work
properly for them.

Thanks to Eric for pointing this out, and the patch review.

Reported-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: devtmpfs: fix compile failure with CONFIG_UIDGID_STRICT_TYPE_CHECKS

If CONFIG_UIDGID_STRICT_TYPE_CHECKS is enalbed, the below compile
failure will be triggered:

drivers/base/devtmpfs.c: In function 'handle_create':
drivers/base/devtmpfs.c:214:19: error: incompatible types when assigning to type 'kuid_t' from type 'uid_t'
drivers/base/devtmpfs.c:215:19: error: incompatible types when assigning to type 'kgid_t' from type 'gid_t'
make[2]: *** [drivers/base/devtmpfs.o] Error 1

This patch fixes the compile failure.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

devtmpfs: add base.h include

This fixes a sparse warning, and is a good idea given that the
devtmpfs_init() prototype is in this file.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: add uid and gid to devtmpfs

Some drivers want to tell userspace what uid and gid should be used for
their device nodes, so allow that information to percolate through the
driver core to userspace in order to make this happen. This means that
some systems (i.e. Android and friends) will not need to even run a
udev-like daemon for their device node manager and can just rely in
devtmpfs fully, reducing their footprint even more.

Signed-off-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

switch vfs_getattr() to struct path

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

vfs: turn is_dir argument to kern_path_create into a lookup_flags arg

Where we can pass in LOOKUP_DIRECTORY or LOOKUP_REVAL. Any other flags
passed in here are currently ignored.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

userns: Convert devtmpfs to use GLOBAL_ROOT_UID and GLOBAL_ROOT_GID

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

new helper: done_path_create()

releases what needs to be released after {kern,user}_path_create()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

get rid of kern_path_parent()

all callers want the same thing, actually - a kinda-sorta analog of
kern_path_create(). I.e. they want parent vfsmount/dentry (with
->i_mutex held, to make sure the child dentry is still their child)
+ the child dentry.

Signed-off-by Al Viro <viro@zeniv.linux.org.uk>

devtmpfs: fix 'the the' typo

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

switch devtmpfs to umode_t

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

switch device_get_devnode() and ->devnode() to umode_t *

both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

devtmpfsd: fix task state handling

- Set the state to TASK_INTERRUPTIBLE using __set_current_state()
instead of set_current_state() as the spin_unlock is an implicit memory
barrier.

- After return from schedule(), there is no need to set the current
state to TASK_RUNNING - a call to schedule() always returns in
TASK_RUNNING state.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/devtmpfs.c: correct annotation of `setup_done'

This fixes the following section mismatch issue:

WARNING: vmlinux.o(.text+0x1192bf): Section mismatch in reference from the function devtmpfsd() to the variable .init.data:setup_done
The function devtmpfsd() references the variable __initdata setup_done.
This is often because devtmpfsd lacks a __initdata annotation or the annotation of setup_done is wrong.

WARNING: vmlinux.o(.text+0x119342): Section mismatch in reference from the function devtmpfsd() to the variable .init.data:setup_done
The function devtmpfsd() references the variable __initdata setup_done.
This is often because devtmpfsd lacks a __initdata annotation or the annotation of setup_done is wrong.

Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

devtmpfs: missing initialialization in never-hit case

create_path() on something without a single / in it will return err
without initializing it. It actually can't happen (we call that thing
only if create on the same path returns -ENOENT, which won't happen
happen for single-component path), but in this case initializing err
to 0 is more than making compiler to STFU - would be the right thing
to return on such paths; the function creates a parent directory of
given pathname and in that case it has no work to do...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fix devtmpfs race

After we's done complete(&req->done), there's nothing to prevent the
scope containing *req from being gone and *req overwritten by any
kind of junk. So we must read req->next before that...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

devtmpfs: get rid of bogus mkdir in create_path()

We do _NOT_ want to mkdir the path itself - we are preparing to
mknod it, after all. Normally it'll fail with -ENOENT and
just do nothing, but if somebody has created the parent in
the meanwhile, we'll get buggered...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

switch devtmpfs to kern_path_create()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

switch devtmpfs object creation/removal to separate kernel thread

... and give it a namespace where devtmpfs would be mounted on root,
thus avoiding abuses of vfs_path_lookup() (it was never intended to
be used with LOOKUP_PARENT). Games with credentials are also gone.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

convert get_sb_single() users

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

devtmpfs: support !CONFIG_TMPFS

Make devtmpfs available on (embedded) configurations without SHMEM/TMPFS,
using ramfs instead.

Saves ~15KB.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Driver-Core: devtmpfs - reset inode permissions before unlinking

Before unlinking the inode, reset the current permissions of possible
references like hardlinks, so granted permissions can not be retained
across the device lifetime by creating hardlinks, in the unusual case
that there is a user-writable directory on the same filesystem.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

driver-core: fix devtmpfs crash on s390

On Mon, Jan 18, 2010 at 05:26:20PM +0530, Sachin Sant wrote:
> Hello Heiko,
>
> Today while trying to boot next-20100118 i came across
> the following Oops :
>
> Brought up 4 CPUs
> Unable to handle kernel pointer dereference at virtual kernel address 0000000000
> 543000
> Oops: 0004 #1 SMP
> Modules linked in:
> CPU: 0 Not tainted 2.6.33-rc4-autotest-next-20100118-5-default #1
> Process swapper (pid: 1, task: 00000000fd792038, ksp: 00000000fd797a30)
> Krnl PSW : 0704200180000000 00000000001eb0b8 (shmem_parse_options+0xc0/0x328)
> R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3
> Krnl GPRS: 000000000054388a 000000000000003d 0000000000543836 000000000000003d
> 0000000000000000 0000000000483f28 0000000000536112 00000000fd797d00
> 00000000fd4ba100 0000000000000100 0000000000483978 0000000000543832
> 0000000000000000 0000000000465958 00000000001eb0b0 00000000fd797c58
> Krnl Code: 00000000001eb0aa: c0e5000994f1 brasl %r14,31da8c
> 00000000001eb0b0: b9020022 ltgr %r2,%r2
> 00000000001eb0b4: a784010b brc 8,1eb2ca
> >00000000001eb0b8: 92002000 mvi 0(%r2),0
> 00000000001eb0bc: a7080000 lhi %r0,0
> 00000000001eb0c0: 41902001 la %r9,1(%r2)
> 00000000001eb0c4: b9040016 lgr %r1,%r6
> 00000000001eb0c8: b904002b lgr %r2,%r11
> Call Trace:
> (<00000000fd797c50> 0xfd797c50)
> <00000000001eb5da> shmem_fill_super+0x13a/0x25c
> <0000000000228cfa> get_sb_single+0xbe/0xdc
> <000000000034ffc0> dev_get_sb+0x2c/0x38
> <000000000066c602> devtmpfs_init+0x46/0xc0
> <000000000066c53e> driver_init+0x22/0x60
> <000000000064d40a> kernel_init+0x24e/0x3d0
> <000000000010a7ea> kernel_thread_starter+0x6/0xc
> <000000000010a7e4> kernel_thread_starter+0x0/0xc
>
> I never tried to boot a kernel with DEVTMPFS enabled on a s390 box.
> So am wondering if this is supported or not ? If you think this
> is supported i will send a mail to community on this.

There is nothing arch specific to devtmpfs. This part crashes because the
kernel tries to modify the data read-only section which is write protected
on s390.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

devtmpfs: unlock mutex in case of string allocation error

Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

devtmpfs: Convert dirlock to a mutex

devtmpfs has a rw_lock dirlock which serializes delete_path and
create_path.

This code was obviously never tested with the usual set of debugging
facilities enabled. In the dirlock held sections the code calls:

- vfs functions which take mutexes
- kmalloc(, GFP_KERNEL)

In both code pathes the might sleep warning triggers and spams dmesg.

Convert the rw_lock to a mutex. There is no reason why this needs to
be a rwlock.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Driver-Core: devtmpfs - set root directory mode to 0755

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mark Rosenstand <rosenstand@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Driver Core: devtmpfs: do not remove non-kernel-created directories

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Driver Core: devtmpfs: use sys_mount()

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Driver core: devtmpfs: prevent concurrent subdirectory creation and removal

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Driver Core: devtmpfs: ignore umask while setting file mode

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Driver-Core: extend devnode callbacks to provide permissions

This allows subsytems to provide devtmpfs with non-default permissions
for the device node. Instead of the default mode of 0600, null, zero,
random, urandom, full, tty, ptmx now have a mode of 0666, which allows
non-privileged processes to access standard device nodes in case no
other userspace process applies the expected permissions.

This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev

Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.

Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.

If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.

If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.

It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>