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Add support for mkdir(2), rmdir(2) and rename(2) syscalls. This is
implemented through optional kernfs_dir_ops callback table which can
be specified on kernfs_create_root(). An implemented callback is
invoked when the matching syscall is invoked.
As kernfs keep dcache syncs with internal representation and
revalidates dentries on each access, the implementation of these
methods is extremely simple. Each just discovers the relevant
kernfs_node(s) and invokes the requested callback which is allowed to
do any kernfs operations and the end result doesn't necessarily have
to match the expected semantics of the syscall.
This will be used to convert cgroup to use kernfs instead of its own
filesystem implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Because sysfs used struct attribute which are supposed to stay
constant, sysfs didn't copy names when creating regular files. The
specified string for name was supposed to stay constant. Such
distinction isn't inherent for kernfs. kernfs_create_file[_ns]()
should be able to take the same @name as kernfs_create_dir[_ns]()
As there can be huge number of sysfs attributes, we still want to be
able to use static names for sysfs attributes. This patch renames
kernfs_create_file_ns_key() to __kernfs_create_file() and adds
@name_is_static parameter so that the caller can explicitly indicate
that @name can be used without copying. kernfs is updated to use
KERNFS_STATIC_NAME to distinguish static and copied names.
This patch doesn't introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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sysfs assumed 0755 for all newly created directories and kernfs
inherited it. This assumption is unnecessarily restrictive and
inconsistent with kernfs_create_file[_ns](). This patch adds @mode
parameter to kernfs_create_dir[_ns]() and update uses in sysfs
accordingly. Among others, this will be useful for implementations of
the planned ->mkdir() method.
This patch doesn't introduce any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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_DIR/KERNFS_DIR/
* s/SYSFS_KOBJ_ATTR/KERNFS_FILE/
* s/SYSFS_KOBJ_LINK/KERNFS_LINK/
* s/SYSFS_{TYPE_FLAGS}/KERNFS_{TYPE_FLAGS}/
* s/SYSFS_FLAG_{FLAG}/KERNFS_{FLAG}/
* s/sysfs_type()/kernfs_type()/
* s/SD_DEACTIVATED_BIAS/KN_DEACTIVATED_BIAS/
This patch is strictly rename only and doesn't introduce any
functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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While restructuring the [u]mount path, 4b93dc9b1c68 ("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: Tejun Heo <tj@kernel.org>
Reported-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Tested-by: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/g/20131205031051.GC5135@yliu-dev.sh.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This is v3.14 fix for the same issue that a8b14744429f ("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.
027a485d12e0 ("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, a8b14744429f ("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: Tejun Heo <tj@kernel.org>
Reported-by: Dave Jones <davej@redhat.com>
Link: http://lkml.kernel.org/g/20131203184324.GA11320@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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sysfs_fill_super() takes three params - @sb, @data and @silent - but
uses only @sb. Drop the latter two.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We're in the process of separating out core sysfs functionality into
kernfs which will deal with sysfs_dirents directly. This patch
introduces kernfs_ops which hosts methods kernfs users implement and
updates fs/sysfs/file.c such that sysfs_kf_*() functions populate
kernfs_ops and kernfs_file_*() functions call the matching entries
from kernfs_ops.
kernfs_ops contains the following groups of methods.
* seq_show() - for kernfs files which use seq_file for reads.
* read() - for direct read implementations. Used iff seq_show() is
not implemented.
* write() - for writes.
* mmap() - for mmaps.
Notes:
* sysfs_elem_attr->ops is added so that kernfs_ops can be accessed
from sysfs_dirent. kernfs_ops() helper is added to verify locking
and access the field.
* SYSFS_FLAG_HAS_(SEQ_SHOW|MMAP) added. sd->s_attr->ops is accessible
only while holding active_ref and there are cases where we want to
take different actions depending on which ops are implemented.
These two flags cache whether the two ops are implemented for those.
* kernfs_file_*() no longer test sysfs type but chooses different
behaviors depending on which methods in kernfs_ops are implemented.
The conversions are trivial except for the open path. As
kernfs_file_open() now decides whether to allow read/write accesses
depending on the kernfs_ops implemented, the presence of methods in
kobjs and attribute_bin should be propagated to kernfs_ops.
sysfs_add_file_mode_ns() is updated so that it propagates presence /
absence of the callbacks through _empty, _ro, _wo, _rw kernfs_ops.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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sysfs_open_file will be used as the primary handle for kernfs methods.
Move its definition from fs/sysfs/file.c to include/linux/kernfs.h and
mark the public and private fields.
This is pure relocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We're in the process of separating out core sysfs functionality into
kernfs which will deal with sysfs_dirents directly. This patch
prepares the rest - open, release and poll. There isn't much to do.
Just renaming is enough. As sysfs_file_operations and
sysfs_bin_operations are identical now, use the same file_operations
for both - kernfs_file_operations.
This patch doesn't introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We're in the process of separating out core sysfs functionality into
kernfs which will deal with sysfs_dirents directly. This patch
rearranges mmap path so that the kernfs and sysfs parts are separate.
sysfs_kf_bin_mmap() which handles the interaction with bin_attribute
mmap method is factored out of sysfs_bin_mmap(), which is renamed to
kernfs_file_mmap(). All vma ops are renamed accordingly.
sysfs_bin_mmap() is updated such that it can be used for both file
types. This will eventually allow using the same file_operations for
both file types, which is necessary to separate out kernfs.
This patch doesn't introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We're in the process of separating out core sysfs functionality into
kernfs which will deal with sysfs_dirents directly. This patch
rearranges write path so that the kernfs and sysfs parts are separate.
kernfs_file_write() handles all boilerplate work including buffer
management and locking and invokes sysfs_kf_write() or
sysfs_kf_bin_write() depending on the file type which deals with the
interaction with kobj store or bin_attribute write method.
While this patch changes the order of some operations, it shouldn't
change any visible behavior.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We're in the process of separating out core sysfs functionality into
kernfs which will deal with sysfs_dirents directly. This patch
rearranges read path so that the kernfs and sysfs parts are separate.
* Regular file read path is refactored such that
kernfs_seq_start/next/stop/show() handle all the boilerplate work
including locking and updating event count for poll, while
sysfs_kf_seq_show() deals with interaction with kobj show method.
* Bin file read path is refactored such that kernfs_file_direct_read()
handles all the boilerplate work including buffer management and
locking, while sysfs_kf_bin_read() deals with interaction with
bin_attribute read method.
kernfs_file_read() is added. It invokes either the seq_file or direct
read path depending on the file type. This will eventually allow
using the same file_operations for both file types, which is necessary
to separate out kernfs.
While this patch changes the order of some operations, it shouldn't
change any visible behavior.
v2: Dropped unnecessary zeroing of @count from sysfs_kf_seq_show().
Add comments explaining single_open() behavior. Both suggested by
Pavel.
v3: seq_stop() is called even after seq_start() failed.
kernfs_seq_start() updated so that it doesn't unlock
sysfs_open_file->mutex on failure so that kernfs_seq_stop()
doesn't try to unlock an already unlocked mutex. Reported by
Fengguang.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Introduce kernfs interface to manipulate a directory which takes and
returns sysfs_dirents.
create_dir() is renamed to kernfs_create_dir_ns() and its argumantes
and return value are updated. create_dir() usages are replaced with
kernfs_create_dir_ns() and sysfs_create_subdir() usages are replaced
with kernfs_create_dir(). Dup warnings are handled explicitly by
sysfs users of the kernfs interface.
sysfs_enable_ns() is renamed to kernfs_enable_ns().
This patch doesn't introduce any behavior changes.
v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
v3: kernfs_enable_ns() added.
v4: Refreshed on top of "sysfs: drop kobj_ns_type handling, take #2"
so that this patch removes sysfs_enable_ns().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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->priv
A directory sysfs_dirent points to the associated kobj. A regular or
bin file points to the associated [bin_]attribute. This patch
replaces sysfs_dirent->s_dir.kobj and ->s_attr.[bin_]attr with void *
->priv.
This is to prepare for kernfs interface so that sysfs can specify the
private data in the same way for directories and files. This lower
debuggability but not by much - the whole thing was overlaid in a
union anyway. If debuggability becomes an issue, we can later add
->priv accessors which explicitly check for the sysfs_dirent type and
performs casting.
This patch doesn't introduce any behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need those sysfs fixes in this branch to make testing, and future
patches apply properly.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Introduce kernfs setattr interface - kernfs_setattr().
sysfs_sd_setattr() is renamed to __kernfs_setattr() and
kernfs_setattr() is a simple wrapper around it with sysfs_mutex
locking. sysfs_chmod_file() is updated to get an explicit ref on
kobj->sd and then invoke kernfs_setattr() so that it doesn't have to
use internal interface.
This patch doesn't introduce any behavior differences.
v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Introduce kernfs rename interface, krenfs_rename[_ns]().
This is just rename of sysfs_rename(). No functional changes.
Function comment is added to kernfs_rename_ns() and @new_parent_sd is
renamed to @new_parent for consistency with other kernfs interfaces.
v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Separate out kernfs symlink interface - kernfs_create_link() - which
takes and returns sysfs_dirents, from sysfs_do_create_link_sd().
sysfs_do_create_link_sd() now just determines the parent and target
sysfs_dirents and invokes the new interface and handles dup warning.
This patch doesn't introduce behavior changes.
v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Introduce kernfs removal interfaces - kernfs_remove() and
kernfs_remove_by_name[_ns]().
These are just renames of sysfs_remove() and sysfs_hash_and_remove().
No functional changes.
v2: Dummy kernfs_remove_by_name_ns() for !CONFIG_SYSFS updated to
return -ENOSYS instead of 0.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently the kobject based interface guarantees that a parent
sysfs_dirent is always a directory; however, the planned kernfs
interface will be directly based on sysfs_dirents and the caller may
specify non-directory node as the parent. Add an explicit check in
__sysfs_add_one() so that such attempts fail with -EINVAL.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The way namespace tags are implemented in sysfs is more complicated
than necessary. As each tag is a pointer value and required to be
non-NULL under a namespace enabled parent, there's no need to record
separately what type each tag is. If multiple namespace types are
needed, which currently aren't, we can simply compare the tag to a set
of allowed tags in the superblock assuming that the tags, being
pointers, won't have the same value across multiple types.
This patch rips out kobj_ns_type handling from sysfs. sysfs now has
an enable switch to turn on namespace under a node. If enabled, all
children are required to have non-NULL namespace tags and filtered
against the super_block's tag.
kobject namespace determination is now performed in
lib/kobject.c::create_dir() making sysfs_read_ns_type() unnecessary.
The sanity checks are also moved. create_dir() is restructured to
ease such addition. This removes most kobject namespace knowledge
from sysfs proper which will enable proper separation and layering of
sysfs.
This is the second try. The first one was cb26a311578e ("sysfs: drop
kobj_ns_type handling") which tried to automatically enable namespace
if there are children with non-NULL namespace tags; however, it was
broken for symlinks as they should inherit the target's tag iff
namespace is enabled in the parent. This led to namespace filtering
enabled incorrectly for wireless net class devices through phy80211
symlinks and thus network configuration failure. a1212d278c05
("Revert "sysfs: drop kobj_ns_type handling"") reverted the commit.
This shouldn't introduce any behavior changes, for real.
v2: Dummy implementation of sysfs_enable_ns() for !CONFIG_SYSFS was
missing and caused build failure. Reported by kbuild test robot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 54d71145a4548330313ca664a4a009772fe8b7dd.
The root cause of these "inverted" sysfs removals have now been found,
so there is no need for this patch. Keep this functionality around so
that this type of error doesn't show up in driver code again.
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The following two commits implemented mmap support in the regular file
path and merged bin file support into the regular path.
73d9714627ad ("sysfs: copy bin mmap support from fs/sysfs/bin.c to fs/sysfs/file.c")
3124eb1679b2 ("sysfs: merge regular and bin file handling")
After the merge, the following commands trigger a spurious lockdep
warning. "test-mmap-read" simply mmaps the file and dumps the
content.
$ cat /sys/block/sda/trace/act_mask
$ test-mmap-read /sys/devices/pci0000\:00/0000\:00\:03.0/resource0 4096
======================================================
[ INFO: possible circular locking dependency detected ]
3.12.0-work+ #378 Not tainted
-------------------------------------------------------
test-mmap-read/567 is trying to acquire lock:
(&of->mutex){+.+.+.}, at: [<ffffffff8120a8df>] sysfs_bin_mmap+0x4f/0x120
but task is already holding lock:
(&mm->mmap_sem){++++++}, at: [<ffffffff8114b399>] vm_mmap_pgoff+0x49/0xa0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&mm->mmap_sem){++++++}:
...
-> #2 (sr_mutex){+.+.+.}:
...
-> #1 (&bdev->bd_mutex){+.+.+.}:
...
-> #0 (&of->mutex){+.+.+.}:
...
other info that might help us debug this:
Chain exists of:
&of->mutex --> sr_mutex --> &mm->mmap_sem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&mm->mmap_sem);
lock(sr_mutex);
lock(&mm->mmap_sem);
lock(&of->mutex);
*** DEADLOCK ***
1 lock held by test-mmap-read/567:
#0: (&mm->mmap_sem){++++++}, at: [<ffffffff8114b399>] vm_mmap_pgoff+0x49/0xa0
stack backtrace:
CPU: 3 PID: 567 Comm: test-mmap-read Not tainted 3.12.0-work+ #378
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
ffffffff81ed41a0 ffff880009441bc8 ffffffff81611ad2 ffffffff81eccb80
ffff880009441c08 ffffffff8160f215 ffff880009441c60 ffff880009c75208
0000000000000000 ffff880009c751e0 ffff880009c75208 ffff880009c74ac0
Call Trace:
[<ffffffff81611ad2>] dump_stack+0x4e/0x7a
[<ffffffff8160f215>] print_circular_bug+0x2b0/0x2bf
[<ffffffff8109ca0a>] __lock_acquire+0x1a3a/0x1e60
[<ffffffff8109d6ba>] lock_acquire+0x9a/0x1d0
[<ffffffff81615547>] mutex_lock_nested+0x67/0x3f0
[<ffffffff8120a8df>] sysfs_bin_mmap+0x4f/0x120
[<ffffffff8115d363>] mmap_region+0x3b3/0x5b0
[<ffffffff8115d8ae>] do_mmap_pgoff+0x34e/0x3d0
[<ffffffff8114b3ba>] vm_mmap_pgoff+0x6a/0xa0
[<ffffffff8115be3e>] SyS_mmap_pgoff+0xbe/0x250
[<ffffffff81008282>] SyS_mmap+0x22/0x30
[<ffffffff8161a4d2>] system_call_fastpath+0x16/0x1b
This happens because one file nests sr_mutex, which nests mm->mmap_sem
under it, under of->mutex while mmap implementation naturally nests
of->mutex under mm->mmap_sem. The warning is false positive as
of->mutex is per open-file and the two paths belong to two different
files. This warning didn't trigger before regular and bin file
supports were merged because only bin file supported mmap and the
other side of locking happened only on regular files which used
equivalent but separate locking.
It'd be best if we give separate locking classes per file but we can't
easily do that. Let's differentiate on ->mmap() for now. Later we'll
add explicit file operations struct and can add per-ops lockdep key
there.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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