Commit Graph

70 Commits

Author SHA1 Message Date
Eric W. Biederman
7d0c7d676c sysfs: Make sysfs_mount static
This patch modifies the users of sysfs_mount to use sysfs_root
instead (which is what they are looking for).  It then
makes sysfs_mount static to keep people from using it
by accident.

The net result is slightly faster and cleaner code.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:07 -07:00
Eric W. Biederman
119dd52be3 sysfs: Remove sysfs_instantiate
Now that sysfs_get_inode is dropping the inode lock
we no longer have a need from sysfs_instantiate.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:07 -07:00
Eric W. Biederman
372e88bd19 sysfs: Move all of inode initialization into sysfs_init_inode
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:07 -07:00
Tejun Heo
253280267a sysfs: fix i_mutex locking in sysfs_get_dentry()
lookup_one_len_kern() should be called with the parent's i_mutex
locked.  Fix it.

Spotted by Eric W. Biederman.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:07 -07:00
Tejun Heo
990e53f880 sysfs: make sysfs_addrm_finish() return void
With the previous sysfs_add_one() update, there is only one user of
the return value of sysfs_addrm_finish() and the user can switch to
testing @sd easily.  Make sysfs_addrm_finish() return void for cleaner
semantics as suggested by Satyam Sharma.

This patch doesn't introduce any noticeable behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Satyam Sharma <satyam.sharma@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:04 -07:00
Tejun Heo
23dc279950 sysfs: make sysfs_add_one() automatically check for duplicate entry
Make sysfs_add_one() check for duplicate entry and return -EEXIST if
such entry exists.  This simplifies node addition code a bit.

This patch doesn't introduce any noticeable behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:04 -07:00
Tejun Heo
41fc1c2745 sysfs: make sysfs_add/remove_one() call link/unlink_sibling() implictly
When adding or removing a sysfs_dirent, the user used to be required
to call link/unlink separately.  It was for two reasons - code looked
like that before sysfs_addrm_cxt conversion and to avoid looping
through parent_sd->children list twice during removal.

Performance optimization during removal just isn't worth it.  Make
sysfs_add/remove_one() call sysfs_link/unlink_sibing() implicitly.
This makes code simpler albeit slightly less efficient.  This change
doesn't introduce any noticeable behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:03 -07:00
Tejun Heo
ff869de7bf sysfs: simplify sysfs_rename_dir()
With the shadow directories gone, sysfs_rename_dir() can be simplified.

* parent doesn't need to be grabbed separately.  Just access
  old_dentry->d_parent.

* parent sd can never change.  Remove code to move under the new
  parent.

* Massage comments a bit.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:03 -07:00
Tejun Heo
a7a0475497 sysfs: cosmetic changes in sysfs_lookup()
* remove space between * and symbol name in variable declaration.

* kill unnecessary new line.

* kill 'found' and test 'sd' instead.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:03 -07:00
Eric W. Biederman
90bc61359d sysfs: Remove first pass at shadow directory support
While shadow directories appear to be a good idea, the current scheme
of controlling their creation and destruction outside of sysfs appears
to be a locking and maintenance nightmare in the face of sysfs
directories dynamically coming and going.  Which can now occur for
directories containing network devices when CONFIG_SYSFS_DEPRECATED is
not set.

This patch removes everything from the initial shadow directory support
that allowed the shadow directory creation to be controlled at a higher
level.  So except for a few bits of sysfs_rename_dir everything from
commit b592fcfe7f is now gone.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:03 -07:00
Dave Young
869512ab5a sysfs: cleanup semaphore.h
Cleanup semaphore.h

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:03 -07:00
Greg Kroah-Hartman
19c38de88a kobjects: fix up improper use of the kobject name field
A number of different drivers incorrect access the kobject name field
directly.  This is not correct as the name might not be in the array.
Use the proper accessor function instead.
2007-10-12 14:51:02 -07:00
Tejun Heo
6cb52147b2 sysfs: fix locking in sysfs_lookup() and sysfs_rename_dir()
sd children list walking in sysfs_lookup() and sd renaming in
sysfs_rename_dir() were left out during i_mutex -> sysfs_mutex
conversion.  Fix them.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-08-22 14:35:34 -07:00
Tejun Heo
967e35dcc9 sysfs: cosmetic clean up on node creation failure paths
Node addition failure is detected by testing return value of
sysfs_addfm_finish() which returns the number of added and removed
nodes.  As the function is called as the last step of addition right
on top of error handling block, the if blocks looked like the
following.

	if (sysfs_addrm_finish(&acxt))
		success handling, usually return;
	/* fall through to error handling */

This is the opposite of usual convention in sysfs and makes the code
difficult to understand.  This patch inverts the test and makes those
blocks look more like others.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Gabriel C <nix.or.die@googlemail.com>
Cc: Miles Lane <miles.lane@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-18 15:49:50 -07:00
Akinobu Mita
01da2425f3 sysfs: avoid kmem_cache_free(NULL)
kmem_cache_free() with NULL is not allowed. But it may happen
if out of memory error is triggered in sysfs_new_dirent().
This patch fixes that error handling.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-18 15:49:49 -07:00
Tejun Heo
51225039f3 sysfs: make directory dentries and inodes reclaimable
This patch makes dentries and inodes for sysfs directories
reclaimable.

* sysfs_notify() is modified to walk sysfs_dirent tree instead of
  dentry tree.

* sysfs_update_file() and sysfs_chmod_file() use sysfs_get_dentry() to
  grab the victim dentry.

* sysfs_rename_dir() and sysfs_move_dir() grab all dentries using
  sysfs_get_dentry() on startup.

* Dentries for all shadowed directories are pinned in memory to serve
  as lookup start point.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:09 -07:00
Tejun Heo
53e0ae9269 sysfs: implement sysfs_get_dentry()
Some sysfs operations require dentry and inode.  sysfs_get_dentry()
looks up and gets dentry for the specified sysfs_dirent.  It finds the
first ancestor with dentry attached and starts looking up dentries
from there.

Looking up from the nearest ancestor is necessary to support shadowed
directories because we can't reliably lookup dentry for one of the
shadows.  Dentries for each shadow will be pinned in memory such that
they can serve as the starting point for dentry lookup.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:09 -07:00
Tejun Heo
a0edd7c848 sysfs: move sysfs_drop_dentry() to dir.c and make it static
After add/remove path restructuring, the only user of
sysfs_drop_dentry() is sysfs_addrm_finish().  Move sysfs_drop_dentry()
to dir.c and make it static.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:09 -07:00
Tejun Heo
fb6896da37 sysfs: restructure add/remove paths and fix inode update
The original add/remove code had the following problems.

* parent's timestamps are updated on dentry instantiation.  this is
  incorrect with reclaimable files.

* updating parent's timestamps isn't synchronized.

* parent nlink update assumes the inode is accessible which won't be
  true once directory dentries are made reclaimable.

This patch restructures add/remove paths to resolve the above
problems.  Add/removal are done in the following steps.

1. sysfs_addrm_start() : acquire locks including sysfs_mutex and other
   resources.

2-a. sysfs_add_one() : add new sd.  linking the new sd into the
     children list is caller's responsibility.

2-b. sysfs_remove_one() : remove a sd.  unlinking the sd from the
     children list is caller's responsibility.

3. sysfs_addrm_finish() : release all resources and clean up.

Steps 2-a and/or 2-b can be repeated multiple times.

Parent's inode is looked up during sysfs_addrm_start().  If available
(always at the moment), it's pinned and nlink is updated as sd's are
added and removed.  Timestamps are updated during finish if any sd has
been added or removed.  If parent's inode is not available during
start, sysfs_mutex ensures that parent inode is not created till
add/remove is complete.

All the complexity is contained inside the helper functions.
Especially, dentry/inode handling is properly hidden from the rest of
sysfs which now mostly operate on sysfs_dirents.  As an added bonus,
codes which use these helpers to add and remove sysfs_dirents are now
more structured and simpler.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:09 -07:00
Tejun Heo
3007e997de sysfs: use sysfs_mutex to protect the sysfs_dirent tree
As kobj sysfs dentries and inodes are gonna be made reclaimable,
i_mutex can't be used to protect sysfs_dirent tree.  Use sysfs_mutex
globally instead.  As the whole tree is protected with sysfs_mutex,
there is no reason to keep sysfs_rename_sem.  Drop it.

While at it, add docbook comments to functions which require
sysfs_mutex locking.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:08 -07:00
Tejun Heo
5f9953237f sysfs: consolidate sysfs spinlocks
Replace sysfs_lock and kobj_sysfs_assoc_lock with sysfs_assoc_lock.
sysfs_lock was originally to be used to protect sysfs_dirent tree but
mutex seems better choice, so there is no reason to keep sysfs_lock
separate.  Merge the two spinlocks into one.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:08 -07:00
Tejun Heo
608e266a2d sysfs: make kobj point to sysfs_dirent instead of dentry
As kobj sysfs dentries and inodes are gonna be made reclaimable,
dentry can't be used as naming token for sysfs file/directory, replace
kobj->dentry with kobj->sd.  The only external interface change is
shadow directory handling.  All other changes are contained in kobj
and sysfs.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:08 -07:00
Tejun Heo
f0b0af4792 sysfs: implement sysfs_find_dirent() and sysfs_get_dirent()
Implement sysfs_find_dirent() and sysfs_get_dirent().
sysfs_dirent_exist() is replaced by sysfs_find_dirent().  These will
be used to make directory entries reclamiable.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:08 -07:00
Tejun Heo
380e6fbb72 sysfs: implement SYSFS_FLAG_REMOVED flag
Implement SYSFS_FLAG_REMOVED flag which currently is used only to
improve sanity check in sysfs_deactivate().  The flag will be used to
make directory entries reclamiable.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:08 -07:00
Tejun Heo
b402d72cf7 sysfs: rename sysfs_dirent->s_type to s_flags and make room for flags
Rename sysfs_dirent->s_type to s_flags, pack type into lower eight
bits and reserve the rest for flags.  sysfs_type() can used to access
the type.  All existing sd->s_type accesses are converted to use
sysfs_type().  While at it, type test is changed to equality test
instead of bit-and test where appropriate.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:08 -07:00
Tejun Heo
0c73f18b7d sysfs: use singly-linked list for sysfs_dirent tree
Make sysfs_dirent use singly linked list for its tree structure.
sysfs_link_sibling() and sysfs_unlink_sibling() functions are added to
handle simpler cases.  It adds some complexity and cpu cycle overhead
but reduced memory footprint is worthwhile on big machines.

This change reduces the sizeof sysfs_dirent from 104 to 88 on 64bit
and from 60 to 52 on 32bit.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:07 -07:00
Tejun Heo
8619f97989 sysfs: slim down sysfs_dirent->s_active
Make sysfs_dirent->s_active an atomic_t instead of rwsem.  This
reduces the size of sysfs_dirent from 136 to 104 on 64bit and from 76
to 60 on 32bit with lock debugging turned off.  With lock debugging
turned on the reduction is much larger.

s_active starts at zero and each active reference increments s_active.
Putting a reference decrements s_active.  Deactivation subtracts
SD_DEACTIVATED_BIAS which is currently INT_MIN and assumed to be small
enough to make s_active negative.  If s_active is negative,
sysfs_get() no longer grants new references.  Deactivation succeeds
immediately if there is no active user; otherwise, it waits using a
completion for the last put.

Due to the removal of lockdep tricks, this change makes things less
trickier in release_sysfs_dirent().  As all the complexity is
contained in three s_active functions, I think it's more readable this
way.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:07 -07:00
Tejun Heo
b6b4a4399c sysfs: move s_active functions to fs/sysfs/dir.c
These functions are about to receive more complexity and doesn't
really need to be inlined in the first place.  Move them from
fs/sysfs/sysfs.h to fs/sysfs/dir.c.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:07 -07:00
Tejun Heo
8312a8d7c1 sysfs: use iget_locked() instead of new_inode()
After dentry is reclaimed, sysfs always used to allocate new dentry
and inode if the file is accessed again.  This causes problem with
operations which only pin the inode.  For example, if inotify watch is
added to a sysfs file and the dentry for the file is reclaimed, the
next update event creates new dentry and new inode making the inotify
watch miss all the events from there on.

This patch fixes it by using iget_locked() instead of new_inode().
sysfs_new_inode() is renamed to sysfs_get_inode() and inode is
initialized iff the inode is newly allocated.  sysfs_instantiate() is
responsible for unlocking new inodes.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:07 -07:00
Tejun Heo
fc9f54b998 sysfs: reorganize sysfs_new_indoe() and sysfs_create()
Reorganize/clean up sysfs_new_inode() and sysfs_create().

* sysfs_init_inode() is separated out from sysfs_new_inode() and is
  responsible for basic initialization.
* sysfs_instantiate() replaces the last step of sysfs_create() and is
  responsible for dentry instantitaion.
* type-specific initialization is moved out to the callers.
* mode is specified only once when creating a sysfs_dirent.
* spurious list_del_init(&sd->s_sibling) dropped from create_dir()

This change is to

* prepare for inode allocation fix.
* separate alloc and init code for synchronization update.
* make dentry/inode initialization more flexible for later changes.

This patch doesn't introduce visible behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:07 -07:00
Tejun Heo
7f7cfffe60 sysfs: fix parent refcounting during rename and move
Parent reference wasn't properly transferred during rename and move.
Fix it.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:07 -07:00
Tejun Heo
42b37df6ab sysfs: make sysfs_alloc_ino() static
sysfs_alloc_ino() isn't used out side of fs/sysfs/dir.c.  Make it
static.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:06 -07:00
Tejun Heo
dbde0fcf9f sysfs: reimplement sysfs_drop_dentry()
This patch reimplements sysfs_drop_dentry() such that remove_dir() can
use it to drop dentry instead of using a separate mechanism.  With
this change, making directories reclaimable is much easier.

This patch used to contain fixes for two race conditions around
sd->s_dentry but that part has been separated out and included into
mainline early as commit 6aa054aadf and
dd14cbc994.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:06 -07:00
Tejun Heo
198a2a8470 sysfs: separate out sysfs_attach_dentry()
Consolidate sd <-> dentry association into sysfs_attach_dentry() and
call it after dentry and inode are properly set up.  This is in
preparation of sysfs_drop_dentry() updates.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:05 -07:00
Tejun Heo
0ab66088c8 sysfs: implement sysfs_dirent active reference and immediate disconnect
sysfs: implement sysfs_dirent active reference and immediate disconnect

Opening a sysfs node references its associated kobject, so userland
can arbitrarily prolong lifetime of a kobject which complicates
lifetime rules in drivers.  This patch implements active reference and
makes the association between kobject and sysfs immediately breakable.

Now each sysfs_dirent has two reference counts - s_count and s_active.
s_count is a regular reference count which guarantees that the
containing sysfs_dirent is accessible.  As long as s_count reference
is held, all sysfs internal fields in sysfs_dirent are accessible
including s_parent and s_name.

The newly added s_active is active reference count.  This is acquired
by invoking sysfs_get_active() and it's the caller's responsibility to
ensure sysfs_dirent itself is accessible (should be holding s_count
one way or the other).  Dereferencing sysfs_dirent to access objects
out of sysfs proper requires active reference.  This includes access
to the associated kobjects, attributes and ops.

The active references can be drained and denied by calling
sysfs_deactivate().  All active sysfs_dirents must be deactivated
after deletion but before the default reference is dropped.  This
enables immediate disconnect of sysfs nodes.  Once a sysfs_dirent is
deleted, it won't access any entity external to sysfs proper.

Because attr/bin_attr ops access both the node itself and its parent
for kobject, they need to hold active references to both.
sysfs_get/put_active_two() helpers are provided to help grabbing both
references.  Parent's is acquired first and released last.

Unlike other operations, mmapped area lingers on after mmap() is
finished and the module implement implementing it and kobj need to
stay referenced till all the mapped pages are gone.  This is
accomplished by holding one set of active references to the bin_attr
and its parent if there have been any mmap during lifetime of an
openfile.  The references are dropped when the openfile is released.

This change makes sysfs lifetime rules independent from both kobject's
and module's.  It not only fixes several race conditions caused by
sysfs not holding onto the proper module when referencing kobject, but
also helps fixing and simplifying lifetime management in driver model
and drivers by taking sysfs out of the equation.

Please read the following message for more info.

  http://article.gmane.org/gmane.linux.kernel/510293

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:05 -07:00
Tejun Heo
2b29ac252a sysfs: reimplement symlink using sysfs_dirent tree
sysfs symlink is implemented by referencing dentry and kobject from
sysfs_dirent - symlink entry references kobject, dentry is used to
walk the tree.  This complicates object lifetimes rules and is
dangerous - for example, there is no way to tell to which module the
target of a symlink belongs and referencing that kobject can make it
linger after the module is gone.

This patch reimplements symlink using only sysfs_dirent tree.  sd for
a symlink points and holds reference to the target sysfs_dirent and
all walking is done using sysfs_dirent tree.  Simpler and safer.

Please read the following message for more info.

  http://article.gmane.org/gmane.linux.kernel/510293

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:04 -07:00
Tejun Heo
aecdcedaab sysfs: implement kobj_sysfs_assoc_lock
kobj->dentry can go away anytime unless the user controls when the
associated sysfs node is deleted.  This patch implements
kobj_sysfs_assoc_lock which protects kobj->dentry.  This will be used
to maintain kobj based API when converting sysfs to use sysfs_dirent
tree instead of dentry/kobject.

Note that this lock belongs to kobject/driver-model not sysfs.  Once
sysfs is converted to not use kobject in its interface, this can be
removed from sysfs.

This is in preparation of object reference simplification.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:04 -07:00
Tejun Heo
3e5190380e sysfs: make sysfs_dirent->s_element a union
Make sd->s_element a union of sysfs_elem_{dir|symlink|attr|bin_attr}
and rename it to s_elem.  This is to achieve...

* some level of type checking : changing symlink to point to
  sysfs_dirent instead of kobject is much safer and less painful now.
* easier / standardized dereferencing
* allow sysfs_elem_* to contain more than one entry

Where possible, pointer is obtained by directly deferencing from sd
instead of going through other entities.  This reduces dependencies to
dentry, inode and kobject.  to_attr() and to_bin_attr() are unused now
and removed.

This is in preparation of object reference simplification.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:04 -07:00
Tejun Heo
0c096b507f sysfs: add sysfs_dirent->s_name
Add s_name to sysfs_dirent.  This is to further reduce dependency to
the associated dentry.  Name is copied for directories and symlinks
but not for attributes.

Where possible, name dereferences are converted to use sd->s_name.
sysfs_symlink->link_name and sysfs_get_name() are unused now and
removed.

This change allows symlink to be implemented using sysfs_dirent tree
proper, which is the last remaining dentry-dependent sysfs walk.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:04 -07:00
Tejun Heo
13b3086d2e sysfs: add sysfs_dirent->s_parent
Add sysfs_dirent->s_parent.  With this patch, each sd points to and
holds a reference to its parent.  This allows walking sysfs tree
without referencing sd->s_dentry which can go away anytime if the user
doesn't control when it's deleted.

sd->s_parent is initialized and parent is referenced in
sysfs_attach_dirent().  Reference to parent is released when the sd is
released, so as long as reference to a sd is held, s_parent can be
followed.

dentry walk in sysfs_readdir() is convereted to s_parent walk.

This will be used to reimplement symlink such that it uses only
sysfs_dirent tree.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:04 -07:00
Tejun Heo
a26cd7226c sysfs: consolidate sysfs_dirent creation functions
Currently there are four functions to create sysfs_dirent -
__sysfs_new_dirent(), sysfs_new_dirent(), __sysfs_make_dirent() and
sysfs_make_dirent().  Other than sysfs_make_dirent(), no function has
two users if calls to implement other functions are excluded.

This patch consolidates sysfs_dirent creation functions into the
following two.

* sysfs_new_dirent() : allocate and initialize
* sysfs_attach_dirent() : attach to sysfs_dirent hierarchy and/or
			  associate with dentry

This simplifies interface and gives callers more flexibility.  This is
in preparation of object reference simplification.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:04 -07:00
Tejun Heo
996b73764e sysfs: flatten and fix sysfs_rename_dir() error handling
Error handling in sysfs_rename_dir() was broken.

* When lookup_one_len() fails, 0 is returned.

* If parent inode check fails, returns with inode mutex and rename
  rwsem held.

This patch fixes the above bugs and flattens error handling such that
it's more readable and easier to modify.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:03 -07:00
Tejun Heo
dfeb9fb034 sysfs: flatten cleanup paths in sysfs_add_link() and create_dir()
Flatten cleanup paths in sysfs_add_link() and create_dir() to improve
readability and ease further changes to these functions.  This is in
preparation of object reference simplification.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:03 -07:00
Tejun Heo
2b611bb7ab sysfs: allocate inode number using ida
sysfs used simple incrementing allocator which is not guaranteed to be
unique.  This patch makes sysfs use ida to give each sd a unique and
packed inode number.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:03 -07:00
Tejun Heo
fa7f912ad4 sysfs: move release_sysfs_dirent() to dir.c
There is no reason this function should be inlined and soon to follow
sysfs object reference simplification will make it heavier.  Move it
to dir.c.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:03 -07:00
Tejun Heo
dd14cbc994 sysfs: fix race condition around sd->s_dentry, take#2
Allowing attribute and symlink dentries to be reclaimed means
sd->s_dentry can change dynamically.  However, updates to the field
are unsynchronized leading to race conditions.  This patch adds
sysfs_lock and use it to synchronize updates to sd->s_dentry.

Due to the locking around ->d_iput, the check in sysfs_drop_dentry()
is complex.  sysfs_lock only protect sd->s_dentry pointer itself.  The
validity of the dentry is protected by dcache_lock, so whether dentry
is alive or not can only be tested while holding both locks.

This is minimal backport of sysfs_drop_dentry() rewrite in devel
branch.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-06-12 16:08:47 -07:00
Eric Sandeen
dc351252b3 sysfs: store sysfs inode nrs in s_ino to avoid readdir oopses
Backport of
ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc1/2.6.22-rc1-mm1/broken-out/gregkh-driver-sysfs-allocate-inode-number-using-ida.patch

For regular files in sysfs, sysfs_readdir wants to traverse
sysfs_dirent->s_dentry->d_inode->i_ino to get to the inode number.
But, the dentry can be reclaimed under memory pressure, and there is
no synchronization with readdir.  This patch follows Tejun's scheme of
allocating and storing an inode number in the new s_ino member of a
sysfs_dirent, when dirents are created, and retrieving it from there
for readdir, so that the pointer chain doesn't have to be traversed.

Tejun's upstream patch uses a new-ish "ida" allocator which brings
along some extra complexity; this -stable patch has a brain-dead
incrementing counter which does not guarantee uniqueness, but because
sysfs doesn't hash inodes as iunique expects, uniqueness wasn't
guaranteed today anyway.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-06-12 16:08:46 -07:00
Mark Lord
0de1517e23 [PATCH] Fix 2.6.21 rfcomm lockups
Any attempt to open/use a bluetooth rfcomm device locks up
scheduling completely on my machine.

Interrupts (ping, alt-sysrq) seem to be alive, but nothing else.

This was working fine in 2.6.20, broken now in 2.6.21-rc2-git*

Reverting this change (below) fixes it:

| author    Marcel Holtmann <marcel@holtmann.org>
|      Sat, 17 Feb 2007 22:58:57 +0000 (23:58 +0100)
| committer    David S. Miller <davem@sunset.davemloft.net>
|      Mon, 26 Feb 2007 19:42:41 +0000 (11:42 -0800)
| commit    c1a3313698
| tree    337a876f72    tree | snapshot
| parent    f5ffd4620a    commit | diff
| | [Bluetooth] Make use of device_move() for RFCOMM TTY devices
| | In the case of bound RFCOMM TTY devices the parent is not available
| before its usage. So when opening a RFCOMM TTY device, move it to
| the corresponding ACL device as a child. When closing the device,
| move it back to the virtual device tree.
| Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

The simplest fix for this bug is to prevent sysfs_move_dir()
from self-deadlocking when (old_parent == new_parent).

This patch prevents total system lockup when using rfcomm devices.

Signed-off-by:  Mark Lord <mlord@pobox.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-06 09:30:24 -08:00
Arjan van de Ven
c5ef1c42c5 [PATCH] mark struct inode_operations const 3
Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:46 -08:00
Robert P. J. Day
c376222960 [PATCH] Transform kmem_cache_alloc()+memset(0) -> kmem_cache_zalloc().
Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the
corresponding "kmem_cache_zalloc()" call.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:27 -08:00