kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

This patch performs the following renames.

* s/sysfs_open_dirent/kernfs_open_node/
* s/sysfs_open_file/kernfs_open_file/
* s/sysfs_inode_attrs/kernfs_iattrs/
* s/sysfs_addrm_cxt/kernfs_addrm_cxt/
* s/sysfs_super_info/kernfs_super_info/
* s/sysfs_info()/kernfs_info()/
* s/sysfs_open_dirent_lock/kernfs_open_node_lock/
* s/sysfs_open_file_mutex/kernfs_open_file_mutex/
* s/sysfs_of()/kernfs_of()/

This patch is strictly rename only and doesn't introduce any
functional difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

s_ prefix for kernfs members is used inconsistently and a misnomer
now.  It's not like kernfs_node is used widely across the kernel
making the ability to grep for the members particularly useful.  Let's
just drop the prefix.

This patch is strictly rename only and doesn't introduce any
functional difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

This patch performs the following renames.

* s/sysfs_elem_dir/kernfs_elem_dir/
* s/sysfs_elem_symlink/kernfs_elem_symlink/
* s/sysfs_elem_attr/kernfs_elem_file/
* s/sysfs_dirent/kernfs_node/
* s/sd/kn/ in kernfs proper
* s/parent_sd/parent/
* s/target_sd/target/
* s/dir_sd/parent/
* s/to_sysfs_dirent()/rb_to_kn()/
* misc renames of local vars when they conflict with the above

Because md, mic and gpio dig into sysfs details, this patch ends up
modifying them.  All are sysfs_dirent renames and trivial.  While we
can avoid these by introducing a dummy wrapping struct sysfs_dirent
around kernfs_node, given the limited usage outside kernfs and sysfs
proper, I don't think such workaround is called for.

This patch is strictly rename only and doesn't introduce any
functional difference.

- mic / gpio renames were missing.  Spotted by kbuild test robot.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

While restructuring the [u]mount path, 4b93dc9b ("sysfs, kernfs:
prepare mount path for kernfs") incorrectly updated sysfs_kill_sb() so
that it first kills super_block and then tries to dereference its
namespace tag to drop it.  Fix it by caching namespace tag before
killing the superblock and then drop the cached namespace tag.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NYuanhan Liu <yuanhan.liu@linux.intel.com>
Tested-by: NYuanhan Liu <yuanhan.liu@linux.intel.com>
Tested-by: NVlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/g/20131205031051.GC5135@yliu-dev.sh.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This is v3.14 fix for the same issue that a8b14744 ("sysfs: give
different locking key to regular and bin files") addresses for v3.13.
Due to the extensive kernfs reorganization in v3.14 branch, the same
fix couldn't be ported as-is.  The v3.13 fix was ignored while merging
it into v3.14 branch.

027a485d ("sysfs: use a separate locking class for open files
depending on mmap") assigned different lockdep key to
sysfs_open_file->mutex depending on whether the file implements mmap
or not in an attempt to avoid spurious lockdep warning caused by
merging of regular and bin file paths.

While this restored some of the original behavior of using different
locks (at least lockdep is concerned) for the different clases of
files.  The restoration wasn't full because now the lockdep key
assignment depends on whether the file has mmap or not instead of
whether it's a regular file or not.

This means that bin files which don't implement mmap will get assigned
the same lockdep class as regular files.  This is problematic because
file_operations for bin files still implements the mmap file operation
and checking whether the sysfs file actually implements mmap happens
in the file operation after grabbing @sysfs_open_file->mutex.  We
still end up adding locking dependency from mmap locking to
sysfs_open_file->mutex to the regular file mutex which triggers
spurious circular locking warning.

For v3.13, a8b14744 ("sysfs: give different locking key to regular
and bin files") fixed it by giving sysfs_open_file->mutex different
lockdep keys depending on whether the file is regular or bin instead
of whether mmap exists or not; however, due to the way sysfs is now
layered behind kernfs, this approach is no longer viable.  kernfs can
tell whether a sysfs node has mmap implemented or not but can't tell
whether a bin file from a regular one.

This patch updates kernfs such that kernfs_file_mmap() checks
SYSFS_FLAG_HAS_MMAP and bail before grabbing sysfs_open_file->mutex so
that it doesn't add spurious locking dependency from mmap to
sysfs_open_file->mutex and changes sysfs so that it specifies
kernfs_ops->mmap iff the sysfs file implements mmap.  Combined, this
ensures that sysfs_open_file->mutex is grabbed under mmap path iff the
sysfs file actually implements mmap.  As sysfs_open_file->mutex is
already given a different lockdep key if mmap is implemented, this
removes the spurious locking dependency.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NDave Jones <davej@redhat.com>
Link: http://lkml.kernel.org/g/20131203184324.GA11320@redhat.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove duplicated include.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

027a485d ("sysfs: use a separate locking class for open files
depending on mmap") assigned different lockdep key to
sysfs_open_file->mutex depending on whether the file implements mmap
or not in an attempt to avoid spurious lockdep warning caused by
merging of regular and bin file paths.

While this restored some of the original behavior of using different
locks (at least lockdep is concerned) for the different clases of
files.  The restoration wasn't full because now the lockdep key
assignment depends on whether the file has mmap or not instead of
whether it's a regular file or not.

This means that bin files which don't implement mmap will get assigned
the same lockdep class as regular files.  This is problematic because
file_operations for bin files still implements the mmap file operation
and checking whether the sysfs file actually implements mmap happens
in the file operation after grabbing @sysfs_open_file->mutex.  We
still end up adding locking dependency from mmap locking to
sysfs_open_file->mutex to the regular file mutex which triggers
spurious circular locking warning.

Fix it by restoring the original behavior fully by differentiating
lockdep key by whether the file is regular or bin, instead of the
existence of mmap.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NDave Jones <davej@redhat.com>
Link: http://lkml.kernel.org/g/20131203184324.GA11320@redhat.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Clean up the aio ring file in the fail path of aio_setup_ring
and ioctx_alloc. And maybe it can fix the GPF issue reported by
Dave Jones:
https://lkml.org/lkml/2013/11/25/898Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>

When compiling a 32bit kernel with CONFIG_LBDAF=n the compiler complains like
shown below.  Fix this warning by instead using sector_div() which is provided
by the kernel.h header file.

fs/nfs/blocklayout/extents.c: In function ‘normalize’:
include/asm-generic/div64.h:43:28: warning: comparison of distinct pointer types lacks a cast [enabled by default]
fs/nfs/blocklayout/extents.c:47:13: note: in expansion of macro ‘do_div’
nfs/blocklayout/extents.c:47:2: warning: right shift count >= width of type [enabled by default]
fs/nfs/blocklayout/extents.c:47:2: warning: passing argument 1 of ‘__div64_32’ from incompatible pointer type [enabled by default]
include/asm-generic/div64.h:35:17: note: expected ‘uint64_t *’ but argument is of type ‘sector_t *’
 extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Andy Adamson reports:

The state manager is recovering expired state and recovery OPENs are being
processed. If kswapd is pruning inodes at the same time, a deadlock can occur
when kswapd calls evict_inode on an NFSv4.1 inode with a layout, and the
resultant layoutreturn gets an error that the state mangager is to handle,
causing the layoutreturn to wait on the (NFS client) cl_rpcwaitq.

At the same time an open is waiting for the inode deletion to complete in
__wait_on_freeing_inode.

If the open is either the open called by the state manager, or an open from
the same open owner that is holding the NFSv4 sequence id which causes the
OPEN from the state manager to wait for the sequence id on the Seqid_waitqueue,
then the state is deadlocked with kswapd.

The fix is simply to have layoutreturn ignore all errors except NFS4ERR_DELAY.
We already know that layouts are dropped on all server reboots, and that
it has to be coded to deal with the "forgetful client model" that doesn't
send layoutreturns.
Reported-by: NAndy Adamson <andros@netapp.com>
Link: http://lkml.kernel.org/r/1385402270-14284-1-git-send-email-andros@netapp.comSigned-off-by: NTrond Myklebust <Trond.Myklebust@primarydata.com>

kernfs inherited "security.*" xattr support from sysfs.  This patch
extends xattr support to "trusted.*" using simple_xattr_*().  As
trusted xattrs are restricted to CAP_SYS_ADMIN, simple_xattr_*() which
uses kernel memory for storage shouldn't be problematic.

Note that the existing "security.*" support doesn't implement
get/remove/list and the this patch only implements those ops for
"trusted.*".  We probably want to extend those ops to include support
for "security.*".

This patch will allow using kernfs from cgroup which requires
"trusted.*" xattr support.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: David P. Quigley <dpquigl@tycho.nsa.gov>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

sysfs_init_inode_attrs() is a bit clumsy to use requiring the caller
to check whether @sd->s_iattr is already set or not.  Rename it to
sysfs_inode_attrs(), update it to check whether @sd->s_iattr is
already initialized before trying to initialize it and return
@sd->s_iattr.  This simplifies the callers.

While at it,

* Rename struct sysfs_inode_attrs pointer variables to "attrs".  As
  kernfs no longer deals with "struct attribute", this isn't confusing
  and makes it easier to distinguish from struct iattr pointers.

* A new field will be added to sysfs_inode_attrs.  Reindent in
  preparation.

This patch doesn't introduce any behavior changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Drop EPOLLWAKEUP from epoll events mask if CONFIG_PM_SLEEP is disabled.
Signed-off-by: NAmit Pundir <amit.pundir@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The pipe code was trying (and failing) to be very careful about freeing
the pipe info only after the last access, with a pattern like:

        spin_lock(&inode->i_lock);
        if (!--pipe->files) {
                inode->i_pipe = NULL;
                kill = 1;
        }
        spin_unlock(&inode->i_lock);
        __pipe_unlock(pipe);
        if (kill)
                free_pipe_info(pipe);

where the final freeing is done last.

HOWEVER.  The above is actually broken, because while the freeing is
done at the end, if we have two racing processes releasing the pipe
inode info, the one that *doesn't* free it will decrement the ->files
count, and unlock the inode i_lock, but then still use the
"pipe_inode_info" afterwards when it does the "__pipe_unlock(pipe)".

This is *very* hard to trigger in practice, since the race window is
very small, and adding debug options seems to just hide it by slowing
things down.

Simon originally reported this way back in July as an Oops in
kmem_cache_allocate due to a single bit corruption (due to the final
"spin_unlock(pipe->mutex.wait_lock)" incrementing a field in a different
allocation that had re-used the free'd pipe-info), it's taken this long
to figure out.

Since the 'pipe->files' accesses aren't even protected by the pipe lock
(we very much use the inode lock for that), the simple solution is to
just drop the pipe lock early.  And since there were two users of this
pattern, create a helper function for it.

Introduced commit ba5bb147 ("pipe: take allocation and freeing of
pipe_inode_info out of ->i_mutex").
Reported-by: NSimon Kirby <sim@hostway.ca>
Reported-by: NIan Applegate <ia@cloudflare.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org   # v3.10+
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/kernfs/kernfs-internal.h needed to include fs/sysfs/sysfs.h because
part of kernfs core implementation was living in sysfs.

fs/sysfs/sysfs.h needed to include fs/kernfs/kernfs-internal.h because
include/linux/kernfs.h didn't expose enough interface.

The separation is complete and neither is true anymore.  Remove the
cross inclusion and make sysfs a proper user of kernfs.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/sysfs/symlink.c::sysfs_delete_link() tests @sd->s_flags for
SYSFS_FLAG_NS.  Let's add kernfs_ns_enabled() so that sysfs doesn't
have to test sysfs_dirent flag directly.  This makes things tidier for
kernfs proper too.

This is purely cosmetic.

v2: To avoid possible NULL deref, use noop dummy implementation which
    always returns false when !CONFIG_SYSFS.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

sysfs_dirent includes some information which should be available to
kernfs users - the type, flags, name and parent pointer.  This patch
moves sysfs_dirent definition from kernfs/kernfs-internal.h to
include/linux/kernfs.h so that kernfs users can access them.

The type part of flags is exported as enum kernfs_node_type, the flags
kernfs_node_flag, sysfs_type() and kernfs_enable_ns() are moved to
include/linux/kernfs.h and the former is updated to return the enum
type.  sysfs_dirent->s_parent and ->s_name are marked explicitly as
public.

This patch doesn't introduce any functional changes.

v2: Flags exported too and kernfs_enable_ns() definition moved.

v3: While moving kernfs_enable_ns() to include/linux/kernfs.h, v1 and
    v2 put the definition outside CONFIG_SYSFS replacing the dummy
    implementation with the actual implementation too.  Unfortunately,
    this can lead to oops when !CONFIG_SYSFS because
    kernfs_enable_ns() may be called on a NULL @sd and now tries to
    dereference @sd instead of not doing anything.  This issue was
    reported by Yuanhan Liu.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NYuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move core mount code to fs/kernfs/mount.c.  The respective
declarations in fs/sysfs/sysfs.h are moved to
fs/kernfs/kernfs-internal.h.

This is pure relocation.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We're in the process of separating out core sysfs functionality into
kernfs which will deal with sysfs_dirents directly.  This patch
rearranges mount path so that the kernfs and sysfs parts are separate.

* As sysfs_super_info won't be visible outside kernfs proper,
  kernfs_super_ns() is added to allow kernfs users to access a
  super_block's namespace tag.

* Generic mount operation is separated out into kernfs_mount_ns().
  sysfs_mount() now just performs sysfs-specific permission check,
  acquires namespace tag, and invokes kernfs_mount_ns().

* Generic superblock release is separated out into kernfs_kill_sb()
  which can be used directly as file_system_type->kill_sb().  As sysfs
  needs to put the namespace tag, sysfs_kill_sb() wraps
  kernfs_kill_sb() with ns tag put.

* sysfs_dir_cachep init and sysfs_inode_init() are separated out into
  kernfs_init().  kernfs_init() uses only small amount of memory and
  trying to handle and propagate kernfs_init() failure doesn't make
  much sense.  Use SLAB_PANIC for sysfs_dir_cachep and make
  sysfs_inode_init() panic on failure.

  After this change, kernfs_init() should be called before
  sysfs_init(), fs/namespace.c::mnt_init() modified accordingly.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

kernfs is being updated to allow multiple sysfs_dirent hierarchies so
that it can also be used by other users.  Currently, sysfs
super_blocks are always attached to one kernfs_root - sysfs_root - and
distinguished only by their namespace tags.

This patch adds sysfs_super_info->root and update
sysfs_fill/test_super() so that super_blocks are identified by the
combination of both the associated kernfs_root and namespace tag.
This allows mounting different kernfs hierarchies.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

kernfs is being updated to allow multiple sysfs_dirent hierarchies so
that it can also be used by other users.  Currently, inode number is
allocated using a global ida, sysfs_ino_ida; however, inos for
different hierarchies should be handled separately.

This patch makes ino allocation per kernfs_root.  sysfs_ino_ida is
replaced by kernfs_root->ino_ida and sysfs_new_dirent() is updated to
take @root and allocate ino from it.  ida_simple_get/remove() are used
instead of sysfs_ino_lock and sysfs_alloc/free_ino().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There currently is single kernfs hierarchy in the whole system which
is used for sysfs.  kernfs needs to support multiple hierarchies to
allow other users.  This patch introduces struct kernfs_root which
serves as the root of each kernfs hierarchy and implements
kernfs_create/destroy_root().

* Each kernfs_root is associated with a root sd (sysfs_dentry).  The
  root is freed when the root sd is released and kernfs_destory_root()
  simply invokes kernfs_remove() on the root sd.  sysfs_remove_one()
  is updated to handle release of the root sd.  Note that ps_iattr
  update in sysfs_remove_one() is trivially updated for readability.

* Root sd's are now dynamically allocated using sysfs_new_dirent().
  Update sysfs_alloc_ino() so that it gives out ino from 1 so that the
  root sd still gets ino 1.

* While kernfs currently only points to the root sd, it'll soon grow
  fields which are specific to each hierarchy.  As determining a given
  sd's root will be necessary, sd->s_dir.root is added.  This backlink
  fits better as a separate field in sd; however, sd->s_dir is inside
  union with space to spare, so use it to save space and provide
  kernfs_root() accessor to determine the root sd.

* As hierarchies may be destroyed now, each mount needs to hold onto
  the hierarchy it's attached to.  Update sysfs_fill_super() and
  sysfs_kill_sb() so that they get and put the kernfs_root
  respectively.

* sysfs_root is replaced with kernfs_root which is dynamically created
  by invoking kernfs_create_root() from sysfs_init().

This patch doesn't introduce any visible behavior changes.

v2: kernfs_create_root() forgot to set @sd->priv.  Fixed.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently, it's assumed that there's a single kernfs hierarchy in the
system anchored at sysfs_root which is defined as a global struct.  To
allow other users of kernfs, this will be made dynamic.  Introduce a
new global variable sysfs_root_sd which points to &sysfs_root and
convert all &sysfs_root users.

This patch doesn't introduce any behavior difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It has been very long since sysfs depended on vfs to keep track of
internal states and whether sysfs is mounted or not doesn't make any
difference to sysfs's internal operation.

In addition to init and filesystem type registration, sysfs_init()
invokes kern_mount() to create in-kernel mount of sysfs.  This
internal mounting doesn't server any purpose anymore.  Remove it.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add const qualifier to sysfs_super_info->ns so that it's consistent
with other namespace tag usages in sysfs.  Because kobject doesn't use
const qualifier for namespace tags, this ends up requiring an explicit
cast to drop const qualifier in free_sysfs_super_info().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

sysfs_fill_super() takes three params - @sb, @data and @silent - but
uses only @sb.  Drop the latter two.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move core symlink code to fs/kernfs/symlink.c.  fs/sysfs/symlink.c now
only contains sysfs wrappers around kernfs interfaces.  The respective
declarations in fs/sysfs/sysfs.h are moved to
fs/kernfs/kernfs-internal.h.

This is pure relocation.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move core file code to fs/kernfs/file.c.  fs/sysfs/file.c now contains
sysfs kernfs_ops callbacks, sysfs wrappers around kernfs interfaces,
and sysfs_schedule_callback().  The respective declarations in
fs/sysfs/sysfs.h are moved to fs/kernfs/kernfs-internal.h.

This is pure relocation.

v2: Refreshed on top of the v2 of "sysfs, kernfs: prepare read path
    for kernfs".

v3: Refreshed on top of the v3 of "sysfs, kernfs: prepare read path
    for kernfs".
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move core dir code to fs/kernfs/dir.c.  fs/sysfs/dir.c now only
contains sysfs_warn_dup() and sysfs wrappers around kernfs interfaces.
The respective declarations in fs/sysfs/sysfs.h are moved to
fs/kernfs/kernfs-internal.h.

This is pure relocation.

v2: sysfs_symlink_target_lock was mistakenly relocated to kernfs.  It
    should remain with sysfs.  Fixed.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There's nothing sysfs-specific in fs/sysfs/inode.c.  Move everything
in it to fs/kernfs/inode.c.  The respective declarations in
fs/sysfs/sysfs.h are moved to fs/kernfs/kernfs-internal.h.

This is pure relocation.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move data structure, constant and basic accessor declarations from
fs/sysfs/sysfs.h to fs/kernfs/kernfs-internal.h.  The two files
currently include each other.  Once kernfs / sysfs separation is
complete, the cross inclusions will be removed.  Inclusion protectors
are added to fs/sysfs/sysfs.h to allow cross-inclusion.

This patch doesn't introduce any functional changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce kernfs interface for finding, getting and putting
sysfs_dirents.

* sysfs_find_dirent() is renamed to kernfs_find_ns() and lockdep
  assertion for sysfs_mutex is added.

* sysfs_get_dirent_ns() is renamed to kernfs_find_and_get().

* Macro inline dancing around __sysfs_get/put() are removed and
  kernfs_get/put() are made proper functions implemented in
  fs/sysfs/dir.c.

While the conversions are mostly equivalent, there's one difference -
kernfs_get() doesn't return the input param as its return value.  This
change is intentional.  While passing through the input increases
writability in some areas, it is unnecessary and has been shown to
cause confusion regarding how the last ref is handled.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently, sysfs_dirent active_ref lockdep annotation uses
attribute->[s]key as the lockdep key, which forces
kernfs_create_file_ns() to assume that sysfs_dirent->priv is pointing
to a struct attribute which may not be true for non-sysfs users.  This
patch restructures the lockdep annotation such that

* kernfs_ops contains lockdep_key which is used by default for files
  created kernfs_create_file_ns().

* kernfs_create_file_ns_key() is introduced which takes an extra @key
  argument.  The created file will use the specified key for
  active_ref lockdep annotation.  If NULL is specified, lockdep for
  the file is disabled.

* sysfs_add_file_mode_ns() is updated to use
  kernfs_create_file_ns_key() with the appropriate key from the
  attribute or NULL if ignore_lockdep is set.

This makes the lockdep annotation properly contained in kernfs while
allowing sysfs to cleanly keep its current behavior.  This patch
doesn't introduce any behavior differences.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We want to add one more SYSFS_FLAG_* but we can't use the next higher
bit, 0x10000, as the flag field is 16bits wide.  The flags are
currently arranged weirdly - 8 bits are set aside for the type flags
when there are only three three used, the first flag starts at 0x1000
instead of 0x0100 and flag literals have 5 digits (20 bits) when only
4 digits can be used.

Rearrange them so that type bits are only the lowest four, flags start
at 0x0010 and similar flags are grouped.

This patch doesn't cause any behavior difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce kernfs interface to wake up poll(2) which takes and returns
sysfs_dirents.

sysfs_notify_dirent() is renamed to kernfs_notify() and sysfs_notify()
is updated so that it doesn't directly grab sysfs_mutex but acquires
the target sysfs_dirents using sysfs_get_dirent().
sysfs_notify_dirent() is reimplemented as a dumb inline wrapper around
kernfs_notify().

This patch doesn't introduce any behavior changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

kernfs_ops currently only supports single_open() behavior which is
pretty restrictive.  Add optional callbacks ->seq_{start|next|stop}()
which, when implemented, are invoked for seq_file traversal.  This
allows full seq_file functionality for kernfs users.  This currently
doesn't have any user and doesn't change any behavior.

v2: Refreshed on top of the updated "sysfs, kernfs: prepare read path
    for kernfs".
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

sysfs_add_one() is a wrapper around __sysfs_add_one() which prints out
duplicate name warning if __sysfs_add_one() fails with -EEXIST.  The
previous kernfs conversions moved all dup warnings to sysfs interface
functions and sysfs_add_one() doesn't have any user left.

Remove sysfs_add_one() and update __sysfs_add_one() to take its name.

This patch doesn't make any functional changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce kernfs interface to create a file which takes and returns
sysfs_dirents.

The actual file creation part is separated out from
sysfs_add_file_mode_ns() into kernfs_create_file_ns().  The former now
only decides the kernfs_ops to use and the file's size and invokes the
latter.

This patch doesn't introduce behavior changes.

v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

After kernfs_ops and sysfs_dirent->s_attr.size addition, the
distinction between SYSFS_KOBJ_BIN_ATTR and SYSFS_KOBJ_ATTR is only
necessary while creating files to decide which kernfs_ops to use.
Afterwards, they behave exactly the same.

This patch removes SYSFS_KOBJ_BIN_ATTR along with sysfs_is_bin().
sysfs_add_file[_mode_ns]() are updated to take bool @is_bin instead of
@type.

This patch doesn't introduce any behavior changes.  This completely
isolates the distinction between the two sysfs file types in the sysfs
layer proper.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

sysfs sets the size of regular files unconditionally at PAGE_SIZE and
takes the size of bin files from bin_attribute.  The latter is a
pretty bad interface which forces bin_attribute users to create a
separate copy of bin_attribute for each instance of the file -
e.g. pci resource files.

Add sysfs_dirent->s_attr.size so that the size can be specified
separately.  This unifies inode init paths of ATTR and BIN_ATTR
identical and allows for generic size handling for kernfs.

Unfortunately, this grows the size of sysfs_dirent by sizeof(loff_t).
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>