linux.git/fs/sysfs/sysfs.h, branch v3.13

Revert "sysfs: drop kobj_ns_type handling"

2013-11-07T11:47:28+00:00

This reverts commit cb26a311578e67769e92a39a0a63476533cb7e12.

It mysteriously causes NetworkManager to not find the wireless device
for me.  As far as I can tell, Tejun *meant* for this commit to not make
any semantic changes, but there clearly are some.  So revert it, taking
into account some of the calling convention changes that happened in
this area in subsequent commits.

Cc: Tejun Heo 
Cc: Greg Kroah-Hartman 
Signed-off-by: Linus Torvalds

sysfs: rename sysfs_assoc_lock and explain what it's about

2013-11-01T19:13:37+00:00

sysfs_assoc_lock is an odd piece of locking.  In general, whoever owns
a kobject is responsible for synchronizing sysfs operations and sysfs
proper assumes that, for example, removal won't race with any other
operation; however, this doesn't work for symlinking because an entity
performing symlink doesn't usually own the target kobject and thus has
no control over its removal.

sysfs_assoc_lock synchronizes symlink operations against kobj->sd
disassociation so that symlink code doesn't end up dereferencing
already freed sysfs_dirent by racing with removal of the target
kobject.

This is quite obscure and the generic name of the lock and lack of
comments make it difficult to understand its role.  Let's rename it to
sysfs_symlink_target_lock and add comments explaining what's going on.

Signed-off-by: Tejun Heo 
Reported-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

sysfs: separate out dup filename warning into a separate function

2013-10-29T22:12:07+00:00

Separate out sysfs_warn_dup() out of sysfs_add_one().  This will help
separating out the core sysfs functionalities into kernfs so that it
can be used by non-sysfs users too.

This doesn't make any functional changes.

Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

sysfs: move sysfs_hash_and_remove() to fs/sysfs/dir.c

2013-10-29T22:12:07+00:00

Most removal related logic is implemented in fs/sysfs/dir.c.  Move
sysfs_hash_and_remove() to fs/sysfs/dir.c so that __sysfs_remove()
doesn't have to be public.

This is pure relocation.

Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

sysfs: remove unused sysfs_get_dentry() prototype

2013-10-29T22:12:07+00:00

sysfs_get_dentry() has been gone for years now.  Remove the left-over
prototype.

Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

sysfs: honor bin_attr.attr.ignore_lockdep

2013-10-29T22:12:07+00:00

ignore_lockdep is currently honored only for regular files.  There's
no reason to ignore it for bin files.  Update sysfs_ignore_lockdep()
so that bin_attr.attr.ignore_lockdep works too.

While this doesn't have any in-kernel user, this unifies the behaviors
between regular and bin files and will help later changes.

Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

sysfs: merge sysfs_elem_bin_attr into sysfs_elem_attr

2013-10-29T22:12:06+00:00

3124eb1679 ("sysfs: merge regular and bin file handling") folded bin
file handling into regular file handling.  Among other things, bin
file now shares the same open path including sysfs_open_dirent
association using sysfs_dirent->s_attr.open.  This is buggy because
->s_bin_attr lives in the same union and doesn't have the field.  This
bug doesn't trigger because sysfs_elem_bin_attr doesn't have an active
field at the conflicting position.  It does have a field "buffers" but
it isn't used anymore.

This patch collapses sysfs_elem_bin_attr into sysfs_elem_attr so that
the bin_attr is accessed through ->s_attr.bin_attr which lives with
->s_attr.attr in an anonymous union.  The code paths already assume
bin_attr contains attr as the first element, so this doesn't add any
more assumptions while making it explicit that the two types are
handled together.

Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

sysfs: make sysfs_file_ops() follow ignore_lockdep flag

2013-10-14T15:40:39+00:00

375b611e60 ("sysfs: remove sysfs_buffer->ops") introduced
sysfs_file_ops() which determines the associated file operation of a
given sysfs_dirent.  As file ops access should be protected by an
active reference, the new function includes a lockdep assertion on the
sysfs_dirent; unfortunately, I forgot to take attr->ignore_lockdep
flag into account and the lockdep assertion trips spuriously for files
which opt out from active reference lockdep checking.

# cat /sys/devices/pci0000:00/0000:00:01.2/usb1/authorized

 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 540 at /work/os/work/fs/sysfs/file.c:79 sysfs_file_ops+0x4e/0x60()
 Modules linked in:
 CPU: 1 PID: 540 Comm: cat Not tainted 3.11.0-work+ #3
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  0000000000000009 ffff880016205c08 ffffffff81ca0131 0000000000000000
  ffff880016205c40 ffffffff81096d0d ffff8800166cb898 ffff8800166f6f60
  ffffffff8125a220 ffff880011ab1ec0 ffff88000aff0c78 ffff880016205c50
 Call Trace:
  [] dump_stack+0x4e/0x82
  [] warn_slowpath_common+0x7d/0xa0
  [] warn_slowpath_null+0x1a/0x20
  [] sysfs_file_ops+0x4e/0x60
  [] sysfs_open_file+0x54/0x300
  [] do_dentry_open.isra.17+0x182/0x280
  [] finish_open+0x30/0x40
  [] do_last+0x503/0xd90
  [] path_openat+0xbb/0x6d0
  [] do_filp_open+0x3a/0x90
  [] do_sys_open+0x129/0x220
  [] SyS_open+0x1e/0x20
  [] system_call_fastpath+0x16/0x1b
 ---[ end trace aa48096b111dafdb ]---

Rename fs/sysfs/dir.c::ignore_lockdep() to sysfs_ignore_lockdep() and
move it to fs/sysfs/sysfs.h and make sysfs_file_ops() skip lockdep
assertion if sysfs_ignore_lockdep() is true.

Signed-off-by: Tejun Heo 
Reported-by: Yinghai Lu 
Signed-off-by: Greg Kroah-Hartman

sysfs: merge regular and bin file handling

2013-10-06T00:27:40+00:00

With the previous changes, sysfs regular file code is ready to handle
bin files too.  This patch makes bin files share the regular file
path.

* sysfs_create/remove_bin_file() are moved to fs/sysfs/file.c.

* sysfs_init_inode() is updated to use the new sysfs_bin_operations
  instead of bin_fops for bin files.

* fs/sysfs/bin.c and the related pieces are removed.

This patch shouldn't introduce any behavior difference to bin file
accesses.

Overall, this unification reduces the amount of duplicate logic, makes
behaviors more consistent and paves the road for building simpler and
more versatile interface which will allow other subsystems to make use
of sysfs for their pseudo filesystems.

v2: Stale fs/sysfs/bin.c reference dropped from
    Documentation/DocBook/filesystems.tmpl.  Reported by kbuild test
    robot.

Signed-off-by: Tejun Heo 
Cc: Kay Sievers 
Cc: kbuild test robot 
Signed-off-by: Greg Kroah-Hartman

sysfs: copy bin mmap support from fs/sysfs/bin.c to fs/sysfs/file.c

2013-10-06T00:27:40+00:00

sysfs bin file handling will be merged into the regular file support.
This patch copies mmap support from bin so that fs/sysfs/file.c can
handle mmapping bin files.

The code is copied mostly verbatim with the following updates.

* ->mmapped and ->vm_ops are added to sysfs_open_file and bin_buffer
  references are replaced with sysfs_open_file ones.

* Symbols are prefixed with sysfs_.

* sysfs_unmap_bin_file() grabs sysfs_open_dirent and traverses
  ->files.  Invocation of this function is added to
  sysfs_addrm_finish().

* sysfs_bin_mmap() is added to sysfs_bin_operations.

This is a preparation and the new mmap path isn't used yet.

Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman