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f0b0af47 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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
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>
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#
380e6fbb |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 entrie
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>
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#
b402d72c |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 t
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>
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0c73f18b |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 sim
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>
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#
8619f979 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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
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>
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b6b4a439 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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: 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>
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#
8312a8d7 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 whic
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>
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#
fc9f54b9 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 fo
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>
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#
7f7cfffe |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 Kro
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>
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42b37df6 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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@
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>
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#
dbde0fcf |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 d
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 6aa054aadfea613a437ad0b15d38eca2b963fc0a and dd14cbc994709a1c5a64ed3621f583c49a27e521.
Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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#
198a2a84 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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_dr
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>
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#
0ab66088 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 kobjec
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>
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#
2b29ac25 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 tre
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>
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#
aecdceda |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 protect
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>
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#
3e519038 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 : chan
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>
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#
0c096b50 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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.
Wher
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>
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13b3086d |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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_dentr
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>
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#
a26cd722 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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()
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>
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#
996b7376 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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
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>
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#
dfeb9fb0 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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
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>
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#
2b611bb7 |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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
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>
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#
fa7f912a |
| 13-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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.
Sign
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>
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#
dd14cbc9 |
| 11-Jun-2007 |
Tejun Heo <htejun@gmail.com> |
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 unsynchron
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>
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#
dc351252 |
| 11-Jun-2007 |
Eric Sandeen <sandeen@sandeen.net> |
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-alloc
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>
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