1. 11 Jul, 2007 40 commits
    • Tejun Heo's avatar
      sysfs: restructure add/remove paths and fix inode update · fb6896da
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      fb6896da
    • Tejun Heo's avatar
      sysfs: use sysfs_mutex to protect the sysfs_dirent tree · 3007e997
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      3007e997
    • Tejun Heo's avatar
      sysfs: consolidate sysfs spinlocks · 5f995323
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      5f995323
    • Tejun Heo's avatar
      sysfs: make kobj point to sysfs_dirent instead of dentry · 608e266a
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      608e266a
    • Tejun Heo's avatar
      sysfs: implement sysfs_find_dirent() and sysfs_get_dirent() · f0b0af47
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      f0b0af47
    • Tejun Heo's avatar
      sysfs: implement SYSFS_FLAG_REMOVED flag · 380e6fbb
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      380e6fbb
    • Tejun Heo's avatar
      sysfs: rename sysfs_dirent->s_type to s_flags and make room for flags · b402d72c
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      b402d72c
    • Tejun Heo's avatar
      sysfs: make sysfs_drop_dentry() access inodes using ilookup() · d0bcb568
      Tejun Heo authored
      sysfs_drop_dentry() used to go through sd->s_dentry and
      sd->s_parent->s_dentry to access the inodes.  This is incorrect
      because inode can be cached without dentry.
      
      This patch makes sysfs_drop_dentry() access inodes using ilookup() on
      sd->s_ino.  This is both correct and simpler.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      d0bcb568
    • Rafael J. Wysocki's avatar
      sysfs: Fix oops in sysfs_drop_dentry on x86_64 · 9d9307da
      Rafael J. Wysocki authored
      Fix oops on x86_64 caused by the dereference of dir in
      sysfs_drop_dentry() made before checking if dir is not NULL
      (cf. http://marc.info/?l=linux-kernel&m=118151626704924&w=2).
      Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      9d9307da
    • Tejun Heo's avatar
      sysfs: use singly-linked list for sysfs_dirent tree · 0c73f18b
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      0c73f18b
    • Tejun Heo's avatar
      sysfs: slim down sysfs_dirent->s_active · 8619f979
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      8619f979
    • Tejun Heo's avatar
      sysfs: move s_active functions to fs/sysfs/dir.c · b6b4a439
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      b6b4a439
    • Tejun Heo's avatar
      sysfs: fix root sysfs_dirent -> root dentry association · 0b8ead82
      Tejun Heo authored
      The root sysfs_dirent didn't point to the root dentry fix it.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      0b8ead82
    • Tejun Heo's avatar
      sysfs: use iget_locked() instead of new_inode() · 8312a8d7
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      8312a8d7
    • Tejun Heo's avatar
      sysfs: reorganize sysfs_new_indoe() and sysfs_create() · fc9f54b9
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      fc9f54b9
    • Tejun Heo's avatar
      sysfs: fix parent refcounting during rename and move · 7f7cfffe
      Tejun Heo authored
      Parent reference wasn't properly transferred during rename and move.
      Fix it.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      7f7cfffe
    • Tejun Heo's avatar
      sysfs: make sysfs_alloc_ino() static · 42b37df6
      Tejun Heo authored
      sysfs_alloc_ino() isn't used out side of fs/sysfs/dir.c.  Make it
      static.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      42b37df6
    • Tejun Heo's avatar
      driver-core: make devt_attr and uevent_attr static · ad6a1e1c
      Tejun Heo authored
      devt_attr and uevent_attr are either allocated dynamically with or
      embedded in device and class_device as they needed their owner field
      set to the module implementing the driver.  Now that sysfs implements
      immediate disconnect and owner field removed from struct attribute,
      there is no reason to do this.  Remove these attributes from
      [class_]device and use static attribute structures instead.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      ad6a1e1c
    • Tejun Heo's avatar
      sysfs: kill unnecessary attribute->owner · 7b595756
      Tejun Heo authored
      sysfs is now completely out of driver/module lifetime game.  After
      deletion, a sysfs node doesn't access anything outside sysfs proper,
      so there's no reason to hold onto the attribute owners.  Note that
      often the wrong modules were accounted for as owners leading to
      accessing removed modules.
      
      This patch kills now unnecessary attribute->owner.  Note that with
      this change, userland holding a sysfs node does not prevent the
      backing module from being unloaded.
      
      For more info regarding lifetime rule cleanup, please read the
      following message.
      
        http://article.gmane.org/gmane.linux.kernel/510293
      
      (tweaked by Greg to not delete the field just yet, to make it easier to
      merge things properly.)
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      7b595756
    • Tejun Heo's avatar
      sysfs: reimplement sysfs_drop_dentry() · dbde0fcf
      Tejun Heo authored
      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 6aa054aa and
      dd14cbc9.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      dbde0fcf
    • Tejun Heo's avatar
      sysfs: separate out sysfs_attach_dentry() · 198a2a84
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      198a2a84
    • Tejun Heo's avatar
      sysfs: kill attribute file orphaning · 73107cb3
      Tejun Heo authored
      Now that sysfs_dirent can be disconnected from kobject on deletion,
      there is no need to orphan each attribute files.  All [bin_]attribute
      nodes are automatically orphaned when the parent node is deleted.
      Kill attribute file orphaning.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      73107cb3
    • Tejun Heo's avatar
      sysfs: implement sysfs_dirent active reference and immediate disconnect · 0ab66088
      Tejun Heo authored
      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/510293Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      0ab66088
    • Tejun Heo's avatar
      sysfs: implement bin_buffer · eb361653
      Tejun Heo authored
      Implement bin_buffer which contains a mutex and pointer to PAGE_SIZE
      buffer to properly synchronize accesses to per-openfile buffer and
      prepare for immediate-kobj-disconnect.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      eb361653
    • Tejun Heo's avatar
      sysfs: reimplement symlink using sysfs_dirent tree · 2b29ac25
      Tejun Heo authored
      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/510293Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      2b29ac25
    • Tejun Heo's avatar
      sysfs: implement kobj_sysfs_assoc_lock · aecdceda
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      aecdceda
    • Tejun Heo's avatar
      sysfs: make sysfs_dirent->s_element a union · 3e519038
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      3e519038
    • Tejun Heo's avatar
      sysfs: add sysfs_dirent->s_name · 0c096b50
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      0c096b50
    • Tejun Heo's avatar
      sysfs: add sysfs_dirent->s_parent · 13b3086d
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      13b3086d
    • Tejun Heo's avatar
      sysfs: consolidate sysfs_dirent creation functions · a26cd722
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      a26cd722
    • Tejun Heo's avatar
      sysfs: flatten and fix sysfs_rename_dir() error handling · 996b7376
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      996b7376
    • Tejun Heo's avatar
      sysfs: flatten cleanup paths in sysfs_add_link() and create_dir() · dfeb9fb0
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      dfeb9fb0
    • Tejun Heo's avatar
      sysfs: fix error handling in binattr write() · 93e3cd82
      Tejun Heo authored
      Error handling in fs/sysfs/bin.c:write() was wrong because size_t
      count is used to receive return value from flush_write() which is
      negative on failure.
      
      This patch updates write() such that int variable is used instead.
      read() is updated the same way for consistency.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      93e3cd82
    • Tejun Heo's avatar
      sysfs: make sysfs_put() ignore NULL sd · 7a23ad44
      Tejun Heo authored
      Make sysfs_put() ignore NULL sd instead of oopsing.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      7a23ad44
    • Tejun Heo's avatar
      sysfs: allocate inode number using ida · 2b611bb7
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      2b611bb7
    • Tejun Heo's avatar
      sysfs: move release_sysfs_dirent() to dir.c · fa7f912a
      Tejun Heo authored
      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: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      fa7f912a
    • Tejun Heo's avatar
      ida: implement idr based id allocator · 72dba584
      Tejun Heo authored
      Implement idr based id allocator.  ida is used the same way idr is
      used but lacks id -> ptr translation and thus consumes much less
      memory.  struct ida_bitmap is attached as leaf nodes to idr tree which
      is managed by the idr code.  Each ida_bitmap is 128bytes long and
      contains slightly less than a thousand slots.
      
      ida is more aggressive with releasing extra resources acquired using
      ida_pre_get().  After every successful id allocation, ida frees one
      reserved idr_layer if possible.  Reserved ida_bitmap is not freed
      automatically but only one ida_bitmap is reserved and it's almost
      always used right away.  Under most circumstances, ida won't hold on
      to memory for too long which isn't actively used.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      72dba584
    • Tejun Heo's avatar
      idr: separate out idr_mark_full() · e33ac8bd
      Tejun Heo authored
      Separate out idr_mark_full() from sub_alloc() and make marking the
      allocated slot full the responsibility of idr_get_new_above_int().
      
      Allocation part of idr_get_new_above_int() is renamed to
      idr_get_empty_slot().  New idr_get_new_above_int() allocates a slot
      using the function, install the user pointer and marks it full using
      idr_mark_full().
      
      This change doesn't introduce any behavior change.  This will be
      used by ida.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      e33ac8bd
    • Tejun Heo's avatar
      idr: fix obscure bug in allocation path · 7aae6dd8
      Tejun Heo authored
      In sub_alloc(), when bitmap search fails, it goes up one level to
      continue search.  This is done by updating the id cursor and searching
      the upper level again.  If the cursor was at the end of the upper
      level, we need to go further than that.
      
      This wasn't implemented and when that happens the part of the cursor
      which indexes into the upper level wraps and sub_alloc() ends up
      searching the wrong bitmap.  It allocates id which doesn't match the
      actual slot.
      
      This patch fixes this by restarting from the top if the search needs
      to go higher than one level.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      
      7aae6dd8
    • Cornelia Huck's avatar
      Driver core: coding style cleanup · dc0afa83
      Cornelia Huck authored
      This converts code of the form
      
      	if ((error = some_func()))
      		goto fixup;
      to
      	error = some_func();
      	if (error)
      		goto fixup;
      Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      dc0afa83