1. 30 Nov, 2013 13 commits
    • Tejun Heo's avatar
      sysfs, kernfs: add kernfs_ops->seq_{start|next|stop}() · d19b9846
      Tejun Heo authored
      
      
      kernfs_ops currently only supports single_open() behavior which is
      pretty restrictive.  Add optional callbacks ->seq_{start|next|stop}()
      which, when implemented, are invoked for seq_file traversal.  This
      allows full seq_file functionality for kernfs users.  This currently
      doesn't have any user and doesn't change any behavior.
      
      v2: Refreshed on top of the updated "sysfs, kernfs: prepare read path
          for kernfs".
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d19b9846
    • Tejun Heo's avatar
      sysfs, kernfs: remove sysfs_add_one() · 2d0cfbec
      Tejun Heo authored
      
      
      sysfs_add_one() is a wrapper around __sysfs_add_one() which prints out
      duplicate name warning if __sysfs_add_one() fails with -EEXIST.  The
      previous kernfs conversions moved all dup warnings to sysfs interface
      functions and sysfs_add_one() doesn't have any user left.
      
      Remove sysfs_add_one() and update __sysfs_add_one() to take its name.
      
      This patch doesn't make any functional changes.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2d0cfbec
    • Tejun Heo's avatar
      sysfs, kernfs: introduce kernfs_create_file[_ns]() · 496f7394
      Tejun Heo authored
      
      
      Introduce kernfs interface to create a file which takes and returns
      sysfs_dirents.
      
      The actual file creation part is separated out from
      sysfs_add_file_mode_ns() into kernfs_create_file_ns().  The former now
      only decides the kernfs_ops to use and the file's size and invokes the
      latter.
      
      This patch doesn't introduce behavior changes.
      
      v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      496f7394
    • Tejun Heo's avatar
      sysfs, kernfs: remove SYSFS_KOBJ_BIN_ATTR · a7dc66df
      Tejun Heo authored
      
      
      After kernfs_ops and sysfs_dirent->s_attr.size addition, the
      distinction between SYSFS_KOBJ_BIN_ATTR and SYSFS_KOBJ_ATTR is only
      necessary while creating files to decide which kernfs_ops to use.
      Afterwards, they behave exactly the same.
      
      This patch removes SYSFS_KOBJ_BIN_ATTR along with sysfs_is_bin().
      sysfs_add_file[_mode_ns]() are updated to take bool @is_bin instead of
      @type.
      
      This patch doesn't introduce any behavior changes.  This completely
      isolates the distinction between the two sysfs file types in the sysfs
      layer proper.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a7dc66df
    • Tejun Heo's avatar
      sysfs, kernfs: add sysfs_dirent->s_attr.size · 471bd7b7
      Tejun Heo authored
      
      
      sysfs sets the size of regular files unconditionally at PAGE_SIZE and
      takes the size of bin files from bin_attribute.  The latter is a
      pretty bad interface which forces bin_attribute users to create a
      separate copy of bin_attribute for each instance of the file -
      e.g. pci resource files.
      
      Add sysfs_dirent->s_attr.size so that the size can be specified
      separately.  This unifies inode init paths of ATTR and BIN_ATTR
      identical and allows for generic size handling for kernfs.
      
      Unfortunately, this grows the size of sysfs_dirent by sizeof(loff_t).
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      471bd7b7
    • Tejun Heo's avatar
      sysfs, kernfs: introduce kernfs_ops · f6acf8bb
      Tejun Heo authored
      
      
      We're in the process of separating out core sysfs functionality into
      kernfs which will deal with sysfs_dirents directly.  This patch
      introduces kernfs_ops which hosts methods kernfs users implement and
      updates fs/sysfs/file.c such that sysfs_kf_*() functions populate
      kernfs_ops and kernfs_file_*() functions call the matching entries
      from kernfs_ops.
      
      kernfs_ops contains the following groups of methods.
      
      * seq_show() - for kernfs files which use seq_file for reads.
      
      * read() - for direct read implementations.  Used iff seq_show() is
        not implemented.
      
      * write() - for writes.
      
      * mmap() - for mmaps.
      
      Notes:
      
      * sysfs_elem_attr->ops is added so that kernfs_ops can be accessed
        from sysfs_dirent.  kernfs_ops() helper is added to verify locking
        and access the field.
      
      * SYSFS_FLAG_HAS_(SEQ_SHOW|MMAP) added.  sd->s_attr->ops is accessible
        only while holding active_ref and there are cases where we want to
        take different actions depending on which ops are implemented.
        These two flags cache whether the two ops are implemented for those.
      
      * kernfs_file_*() no longer test sysfs type but chooses different
        behaviors depending on which methods in kernfs_ops are implemented.
        The conversions are trivial except for the open path.  As
        kernfs_file_open() now decides whether to allow read/write accesses
        depending on the kernfs_ops implemented, the presence of methods in
        kobjs and attribute_bin should be propagated to kernfs_ops.
        sysfs_add_file_mode_ns() is updated so that it propagates presence /
        absence of the callbacks through _empty, _ro, _wo, _rw kernfs_ops.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f6acf8bb
    • Tejun Heo's avatar
      sysfs, kernfs: move sysfs_open_file to include/linux/kernfs.h · dd8a5b03
      Tejun Heo authored
      
      
      sysfs_open_file will be used as the primary handle for kernfs methods.
      Move its definition from fs/sysfs/file.c to include/linux/kernfs.h and
      mark the public and private fields.
      
      This is pure relocation.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      dd8a5b03
    • Tejun Heo's avatar
      sysfs, kernfs: prepare open, release, poll paths for kernfs · c6fb4495
      Tejun Heo authored
      
      
      We're in the process of separating out core sysfs functionality into
      kernfs which will deal with sysfs_dirents directly.  This patch
      prepares the rest - open, release and poll.  There isn't much to do.
      Just renaming is enough.  As sysfs_file_operations and
      sysfs_bin_operations are identical now, use the same file_operations
      for both - kernfs_file_operations.
      
      This patch doesn't introduce any behavior changes.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c6fb4495
    • Tejun Heo's avatar
      sysfs, kernfs: prepare mmap path for kernfs · fdbffaa4
      Tejun Heo authored
      
      
      We're in the process of separating out core sysfs functionality into
      kernfs which will deal with sysfs_dirents directly.  This patch
      rearranges mmap path so that the kernfs and sysfs parts are separate.
      
      sysfs_kf_bin_mmap() which handles the interaction with bin_attribute
      mmap method is factored out of sysfs_bin_mmap(), which is renamed to
      kernfs_file_mmap().  All vma ops are renamed accordingly.
      
      sysfs_bin_mmap() is updated such that it can be used for both file
      types.  This will eventually allow using the same file_operations for
      both file types, which is necessary to separate out kernfs.
      
      This patch doesn't introduce any behavior changes.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      fdbffaa4
    • Tejun Heo's avatar
      sysfs, kernfs: prepare write path for kernfs · 50b38ca0
      Tejun Heo authored
      
      
      We're in the process of separating out core sysfs functionality into
      kernfs which will deal with sysfs_dirents directly.  This patch
      rearranges write path so that the kernfs and sysfs parts are separate.
      
      kernfs_file_write() handles all boilerplate work including buffer
      management and locking and invokes sysfs_kf_write() or
      sysfs_kf_bin_write() depending on the file type which deals with the
      interaction with kobj store or bin_attribute write method.
      
      While this patch changes the order of some operations, it shouldn't
      change any visible behavior.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      50b38ca0
    • Tejun Heo's avatar
      sysfs, kernfs: prepare read path for kernfs · c2b19daf
      Tejun Heo authored
      
      
      We're in the process of separating out core sysfs functionality into
      kernfs which will deal with sysfs_dirents directly.  This patch
      rearranges read path so that the kernfs and sysfs parts are separate.
      
      * Regular file read path is refactored such that
        kernfs_seq_start/next/stop/show() handle all the boilerplate work
        including locking and updating event count for poll, while
        sysfs_kf_seq_show() deals with interaction with kobj show method.
      
      * Bin file read path is refactored such that kernfs_file_direct_read()
        handles all the boilerplate work including buffer management and
        locking, while sysfs_kf_bin_read() deals with interaction with
        bin_attribute read method.
      
      kernfs_file_read() is added.  It invokes either the seq_file or direct
      read path depending on the file type.  This will eventually allow
      using the same file_operations for both file types, which is necessary
      to separate out kernfs.
      
      While this patch changes the order of some operations, it shouldn't
      change any visible behavior.
      
      v2: Dropped unnecessary zeroing of @count from sysfs_kf_seq_show().
          Add comments explaining single_open() behavior.  Both suggested by
          Pavel.
      
      v3: seq_stop() is called even after seq_start() failed.
          kernfs_seq_start() updated so that it doesn't unlock
          sysfs_open_file->mutex on failure so that kernfs_seq_stop()
          doesn't try to unlock an already unlocked mutex.  Reported by
          Fengguang.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c2b19daf
    • Tejun Heo's avatar
      sysfs, kernfs: introduce kernfs_create_dir[_ns]() · 93b2b8e4
      Tejun Heo authored
      
      
      Introduce kernfs interface to manipulate a directory which takes and
      returns sysfs_dirents.
      
      create_dir() is renamed to kernfs_create_dir_ns() and its argumantes
      and return value are updated.  create_dir() usages are replaced with
      kernfs_create_dir_ns() and sysfs_create_subdir() usages are replaced
      with kernfs_create_dir().  Dup warnings are handled explicitly by
      sysfs users of the kernfs interface.
      
      sysfs_enable_ns() is renamed to kernfs_enable_ns().
      
      This patch doesn't introduce any behavior changes.
      
      v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
      
      v3: kernfs_enable_ns() added.
      
      v4: Refreshed on top of "sysfs: drop kobj_ns_type handling, take #2"
          so that this patch removes sysfs_enable_ns().
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      93b2b8e4
    • Tejun Heo's avatar
      sysfs, kernfs: replace sysfs_dirent->s_dir.kobj and ->s_attr.[bin_]attr with ->priv · 7c6e2d36
      Tejun Heo authored
      
      
      A directory sysfs_dirent points to the associated kobj.  A regular or
      bin file points to the associated [bin_]attribute.  This patch
      replaces sysfs_dirent->s_dir.kobj and ->s_attr.[bin_]attr with void *
      ->priv.
      
      This is to prepare for kernfs interface so that sysfs can specify the
      private data in the same way for directories and files.  This lower
      debuggability but not by much - the whole thing was overlaid in a
      union anyway.  If debuggability becomes an issue, we can later add
      ->priv accessors which explicitly check for the sysfs_dirent type and
      performs casting.
      
      This patch doesn't introduce any behavior difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7c6e2d36
  2. 27 Nov, 2013 7 commits
    • Tejun Heo's avatar
      sysfs, kernfs: introduce kernfs_setattr() · 5d60418e
      Tejun Heo authored
      
      
      Introduce kernfs setattr interface - kernfs_setattr().
      
      sysfs_sd_setattr() is renamed to __kernfs_setattr() and
      kernfs_setattr() is a simple wrapper around it with sysfs_mutex
      locking.  sysfs_chmod_file() is updated to get an explicit ref on
      kobj->sd and then invoke kernfs_setattr() so that it doesn't have to
      use internal interface.
      
      This patch doesn't introduce any behavior differences.
      
      v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      5d60418e
    • Tejun Heo's avatar
      sysfs, kernfs: introduce kernfs_rename[_ns]() · 890ece16
      Tejun Heo authored
      
      
      Introduce kernfs rename interface, krenfs_rename[_ns]().
      
      This is just rename of sysfs_rename().  No functional changes.
      Function comment is added to kernfs_rename_ns() and @new_parent_sd is
      renamed to @new_parent for consistency with other kernfs interfaces.
      
      v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      890ece16
    • Tejun Heo's avatar
      sysfs, kernfs: introduce kernfs_create_link() · 5d0e26bb
      Tejun Heo authored
      
      
      Separate out kernfs symlink interface - kernfs_create_link() - which
      takes and returns sysfs_dirents, from sysfs_do_create_link_sd().
      sysfs_do_create_link_sd() now just determines the parent and target
      sysfs_dirents and invokes the new interface and handles dup warning.
      
      This patch doesn't introduce behavior changes.
      
      v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      5d0e26bb
    • Tejun Heo's avatar
      sysfs, kernfs: introduce kernfs_remove[_by_name[_ns]]() · 879f40d1
      Tejun Heo authored
      
      
      Introduce kernfs removal interfaces - kernfs_remove() and
      kernfs_remove_by_name[_ns]().
      
      These are just renames of sysfs_remove() and sysfs_hash_and_remove().
      No functional changes.
      
      v2: Dummy kernfs_remove_by_name_ns() for !CONFIG_SYSFS updated to
          return -ENOSYS instead of 0.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      879f40d1
    • Tejun Heo's avatar
      sysfs: make __sysfs_add_one() fail if the parent isn't a directory · ae2108ad
      Tejun Heo authored
      
      
      Currently the kobject based interface guarantees that a parent
      sysfs_dirent is always a directory; however, the planned kernfs
      interface will be directly based on sysfs_dirents and the caller may
      specify non-directory node as the parent.  Add an explicit check in
      __sysfs_add_one() so that such attempts fail with -EINVAL.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ae2108ad
    • Tejun Heo's avatar
      sysfs: drop kobj_ns_type handling, take #2 · c84a3b27
      Tejun Heo authored
      The way namespace tags are implemented in sysfs is more complicated
      than necessary.  As each tag is a pointer value and required to be
      non-NULL under a namespace enabled parent, there's no need to record
      separately what type each tag is.  If multiple namespace types are
      needed, which currently aren't, we can simply compare the tag to a set
      of allowed tags in the superblock assuming that the tags, being
      pointers, won't have the same value across multiple types.
      
      This patch rips out kobj_ns_type handling from sysfs.  sysfs now has
      an enable switch to turn on namespace under a node.  If enabled, all
      children are required to have non-NULL namespace tags and filtered
      against the super_block's tag.
      
      kobject namespace determination is now performed in
      lib/kobject.c::create_dir() making sysfs_read_ns_type() unnecessary.
      The sanity checks are also moved.  create_dir() is restructured to
      ease such addition.  This removes most kobject namespace knowledge
      from sysfs proper which will enable proper separation and layering of
      sysfs.
      
      This is the second try.  The first one was cb26a311 ("sysfs: drop
      kobj_ns_type handling") which tried to automatically enable namespace
      if there are children with non-NULL namespace tags; however, it was
      broken for symlinks as they should inherit the target's tag iff
      namespace is enabled in the parent.  This led to namespace filtering
      enabled incorrectly for wireless net class devices through phy80211
      symlinks and thus network configuration failure.  a1212d27
      
      
      ("Revert "sysfs: drop kobj_ns_type handling"") reverted the commit.
      
      This shouldn't introduce any behavior changes, for real.
      
      v2: Dummy implementation of sysfs_enable_ns() for !CONFIG_SYSFS was
          missing and caused build failure.  Reported by kbuild test robot.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Cc: Eric W. Biederman <ebiederm@xmission.com>
      Cc: Kay Sievers <kay@vrfy.org>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: kbuild test robot <fengguang.wu@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c84a3b27
    • Greg Kroah-Hartman's avatar
      Revert "sysfs: handle duplicate removal attempts in sysfs_remove_group()" · 81440e73
      Greg Kroah-Hartman authored
      This reverts commit 54d71145
      
      .
      
      The root cause of these "inverted" sysfs removals have now been found,
      so there is no need for this patch.  Keep this functionality around so
      that this type of error doesn't show up in driver code again.
      
      Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
      Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      81440e73
  3. 23 Nov, 2013 2 commits
    • Tejun Heo's avatar
      sysfs: use a separate locking class for open files depending on mmap · 027a485d
      Tejun Heo authored
      The following two commits implemented mmap support in the regular file
      path and merged bin file support into the regular path.
      
       73d97146 ("sysfs: copy bin mmap support from fs/sysfs/bin.c to fs/sysfs/file.c")
       3124eb16
      
       ("sysfs: merge regular and bin file handling")
      
      After the merge, the following commands trigger a spurious lockdep
      warning.  "test-mmap-read" simply mmaps the file and dumps the
      content.
      
        $ cat /sys/block/sda/trace/act_mask
        $ test-mmap-read /sys/devices/pci0000\:00/0000\:00\:03.0/resource0 4096
      
        ======================================================
        [ INFO: possible circular locking dependency detected ]
        3.12.0-work+ #378 Not tainted
        -------------------------------------------------------
        test-mmap-read/567 is trying to acquire lock:
         (&of->mutex){+.+.+.}, at: [<ffffffff8120a8df>] sysfs_bin_mmap+0x4f/0x120
      
        but task is already holding lock:
         (&mm->mmap_sem){++++++}, at: [<ffffffff8114b399>] vm_mmap_pgoff+0x49/0xa0
      
        which lock already depends on the new lock.
      
        the existing dependency chain (in reverse order) is:
      
        -> #3 (&mm->mmap_sem){++++++}:
        ...
        -> #2 (sr_mutex){+.+.+.}:
        ...
        -> #1 (&bdev->bd_mutex){+.+.+.}:
        ...
        -> #0 (&of->mutex){+.+.+.}:
        ...
      
        other info that might help us debug this:
      
        Chain exists of:
         &of->mutex --> sr_mutex --> &mm->mmap_sem
      
         Possible unsafe locking scenario:
      
      	 CPU0                    CPU1
      	 ----                    ----
          lock(&mm->mmap_sem);
      				 lock(sr_mutex);
      				 lock(&mm->mmap_sem);
          lock(&of->mutex);
      
         *** DEADLOCK ***
      
        1 lock held by test-mmap-read/567:
         #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff8114b399>] vm_mmap_pgoff+0x49/0xa0
      
        stack backtrace:
        CPU: 3 PID: 567 Comm: test-mmap-read Not tainted 3.12.0-work+ #378
        Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
         ffffffff81ed41a0 ffff880009441bc8 ffffffff81611ad2 ffffffff81eccb80
         ffff880009441c08 ffffffff8160f215 ffff880009441c60 ffff880009c75208
         0000000000000000 ffff880009c751e0 ffff880009c75208 ffff880009c74ac0
        Call Trace:
         [<ffffffff81611ad2>] dump_stack+0x4e/0x7a
         [<ffffffff8160f215>] print_circular_bug+0x2b0/0x2bf
         [<ffffffff8109ca0a>] __lock_acquire+0x1a3a/0x1e60
         [<ffffffff8109d6ba>] lock_acquire+0x9a/0x1d0
         [<ffffffff81615547>] mutex_lock_nested+0x67/0x3f0
         [<ffffffff8120a8df>] sysfs_bin_mmap+0x4f/0x120
         [<ffffffff8115d363>] mmap_region+0x3b3/0x5b0
         [<ffffffff8115d8ae>] do_mmap_pgoff+0x34e/0x3d0
         [<ffffffff8114b3ba>] vm_mmap_pgoff+0x6a/0xa0
         [<ffffffff8115be3e>] SyS_mmap_pgoff+0xbe/0x250
         [<ffffffff81008282>] SyS_mmap+0x22/0x30
         [<ffffffff8161a4d2>] system_call_fastpath+0x16/0x1b
      
      This happens because one file nests sr_mutex, which nests mm->mmap_sem
      under it, under of->mutex while mmap implementation naturally nests
      of->mutex under mm->mmap_sem.  The warning is false positive as
      of->mutex is per open-file and the two paths belong to two different
      files.  This warning didn't trigger before regular and bin file
      supports were merged because only bin file supported mmap and the
      other side of locking happened only on regular files which used
      equivalent but separate locking.
      
      It'd be best if we give separate locking classes per file but we can't
      easily do that.  Let's differentiate on ->mmap() for now.  Later we'll
      add explicit file operations struct and can add per-ops lockdep key
      there.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarDave Jones <davej@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      027a485d
    • Mika Westerberg's avatar
      sysfs: handle duplicate removal attempts in sysfs_remove_group() · 54d71145
      Mika Westerberg authored
      Commit bcdde7e2
      
       (sysfs: make __sysfs_remove_dir() recursive) changed
      the behavior so that directory removals will be done recursively. This
      means that the sysfs group might already be removed if its parent directory
      has been removed.
      
      The current code outputs warnings similar to following log snippet when it
      detects that there is no group for the given kobject:
      
       WARNING: CPU: 0 PID: 4 at fs/sysfs/group.c:214 sysfs_remove_group+0xc6/0xd0()
       sysfs group ffffffff81c6f1e0 not found for kobject 'host7'
       Modules linked in:
       CPU: 0 PID: 4 Comm: kworker/0:0 Not tainted 3.12.0+ #13
       Hardware name:                  /D33217CK, BIOS GKPPT10H.86A.0042.2013.0422.1439 04/22/2013
       Workqueue: kacpi_hotplug acpi_hotplug_work_fn
        0000000000000009 ffff8801002459b0 ffffffff817daab1 ffff8801002459f8
        ffff8801002459e8 ffffffff810436b8 0000000000000000 ffffffff81c6f1e0
        ffff88006d440358 ffff88006d440188 ffff88006e8b4c28 ffff880100245a48
       Call Trace:
        [<ffffffff817daab1>] dump_stack+0x45/0x56
        [<ffffffff810436b8>] warn_slowpath_common+0x78/0xa0
        [<ffffffff81043727>] warn_slowpath_fmt+0x47/0x50
        [<ffffffff811ad319>] ? sysfs_get_dirent_ns+0x49/0x70
        [<ffffffff811ae526>] sysfs_remove_group+0xc6/0xd0
        [<ffffffff81432f7e>] dpm_sysfs_remove+0x3e/0x50
        [<ffffffff8142a0d0>] device_del+0x40/0x1b0
        [<ffffffff8142a24d>] device_unregister+0xd/0x20
        [<ffffffff8144131a>] scsi_remove_host+0xba/0x110
        [<ffffffff8145f526>] ata_host_detach+0xc6/0x100
        [<ffffffff8145f578>] ata_pci_remove_one+0x18/0x20
        [<ffffffff812e8f48>] pci_device_remove+0x28/0x60
        [<ffffffff8142d854>] __device_release_driver+0x64/0xd0
        [<ffffffff8142d8de>] device_release_driver+0x1e/0x30
        [<ffffffff8142d257>] bus_remove_device+0xf7/0x140
        [<ffffffff8142a1b1>] device_del+0x121/0x1b0
        [<ffffffff812e43d4>] pci_stop_bus_device+0x94/0xa0
        [<ffffffff812e437b>] pci_stop_bus_device+0x3b/0xa0
        [<ffffffff812e437b>] pci_stop_bus_device+0x3b/0xa0
        [<ffffffff812e44dd>] pci_stop_and_remove_bus_device+0xd/0x20
        [<ffffffff812fc743>] trim_stale_devices+0x73/0xe0
        [<ffffffff812fc78b>] trim_stale_devices+0xbb/0xe0
        [<ffffffff812fc78b>] trim_stale_devices+0xbb/0xe0
        [<ffffffff812fcb6e>] acpiphp_check_bridge+0x7e/0xd0
        [<ffffffff812fd90d>] hotplug_event+0xcd/0x160
        [<ffffffff812fd9c5>] hotplug_event_work+0x25/0x60
        [<ffffffff81316749>] acpi_hotplug_work_fn+0x17/0x22
        [<ffffffff8105cf3a>] process_one_work+0x17a/0x430
        [<ffffffff8105db29>] worker_thread+0x119/0x390
        [<ffffffff8105da10>] ? manage_workers.isra.25+0x2a0/0x2a0
        [<ffffffff81063a5d>] kthread+0xcd/0xf0
        [<ffffffff81063990>] ? kthread_create_on_node+0x180/0x180
        [<ffffffff817eb33c>] ret_from_fork+0x7c/0xb0
        [<ffffffff81063990>] ? kthread_create_on_node+0x180/0x180
      
      On this particular machine I see ~16 of these message during Thunderbolt
      hot-unplug.
      
      Fix this in similar way that was done for sysfs_remove_one() by checking
      if the parent directory has already been removed and bailing out early.
      Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
      Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      54d71145
  4. 07 Nov, 2013 1 commit
    • Linus Torvalds's avatar
      Revert "sysfs: drop kobj_ns_type handling" · a1212d27
      Linus Torvalds authored
      This reverts commit cb26a311
      
      .
      
      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 <tj@kernel.org>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a1212d27
  5. 01 Nov, 2013 2 commits
    • Tejun Heo's avatar
      sysfs: rename sysfs_assoc_lock and explain what it's about · 0cae60f9
      Tejun Heo authored
      
      
      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: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      0cae60f9
    • Tejun Heo's avatar
      sysfs: use generic_file_llseek() for sysfs_file_operations · 044e3bc3
      Tejun Heo authored
      13c589d5
      
       ("sysfs: use seq_file when reading regular files")
      converted regular sysfs files to use seq_file.  The commit substituted
      generic_file_llseek() with seq_lseek() for llseek implementation.
      
      Before the change, all regular sysfs files were allowed to seek to any
      position in [0, PAGE_SIZE] as the file size is always PAGE_SIZE and
      generic_file_llseek() allows any seeking inside the range under file
      size; however, seq_lseek()'s behavior is different.  It traverses the
      output by repeatedly invoking ->show() until it reaches the target
      offset or traversal indicates EOF.  As seq_files are fully dynamic and
      may not end at all, it doesn't support seeking from the end
      (SEEK_END).
      
      Apparently, there are userland tools which uses SEEK_END to discover
      the buffer size to use and the switch to seq_lseek() disturbs them as
      SEEK_END fails with -EINVAL.
      
      The only benefits of using seq_lseek() instead of
      generic_file_llseek() are
      
      * Early failure.  If traversing to certain file position should fail,
        seq_lseek() will report such failures on lseek(2) instead of the
        following read/write operations.
      
      * EOF detection.  While SEEK_END is not supported, SEEK_SET/CUR +
        large offset can be used to detect eof - eof at the time of the seek
        anyway as the file size may change dynamically.
      
      Both aren't necessary for sysfs or prospect kernfs users.  Revert to
      genefic_file_llseek() and preserve the original behavior.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Link: https://lkml.kernel.org/r/20131031114358.GA5551@osiris
      
      Tested-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      044e3bc3
  6. 30 Oct, 2013 1 commit
  7. 29 Oct, 2013 5 commits
  8. 25 Oct, 2013 1 commit
  9. 14 Oct, 2013 2 commits
    • Benjamin Herrenschmidt's avatar
      sysfs/bin: Fix size handling overflow for bin_attribute · d723a92d
      Benjamin Herrenschmidt authored
      
      
      While looking at the code, I noticed that bin_attribute read() and write()
      ops copy the inode size into an int for futher comparisons.
      
      Some bin_attributes can be fairly large. For example, pci creates some for
      BARs set to the BAR size and giant BARs are around the corner, so this is
      going to break something somewhere eventually.
      
      Let's use the right type.
      
      [adjust for seqfile conversions, only needed for bin_read() - gkh]
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d723a92d
    • Tejun Heo's avatar
      sysfs: make sysfs_file_ops() follow ignore_lockdep flag · 785a162d
      Tejun Heo authored
      375b611e
      
       ("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:
        [<ffffffff81ca0131>] dump_stack+0x4e/0x82
        [<ffffffff81096d0d>] warn_slowpath_common+0x7d/0xa0
        [<ffffffff81096dea>] warn_slowpath_null+0x1a/0x20
        [<ffffffff8125994e>] sysfs_file_ops+0x4e/0x60
        [<ffffffff8125a274>] sysfs_open_file+0x54/0x300
        [<ffffffff811df612>] do_dentry_open.isra.17+0x182/0x280
        [<ffffffff811df820>] finish_open+0x30/0x40
        [<ffffffff811f0623>] do_last+0x503/0xd90
        [<ffffffff811f0f6b>] path_openat+0xbb/0x6d0
        [<ffffffff811f23ba>] do_filp_open+0x3a/0x90
        [<ffffffff811e09a9>] do_sys_open+0x129/0x220
        [<ffffffff811e0abe>] SyS_open+0x1e/0x20
        [<ffffffff81caf3c2>] 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: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarYinghai Lu <yinghai@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      785a162d
  10. 06 Oct, 2013 6 commits
    • Tejun Heo's avatar
      sysfs: merge regular and bin file handling · 3124eb16
      Tejun Heo authored
      
      
      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: default avatarTejun Heo <tj@kernel.org>
      Cc: Kay Sievers <kay@vrfy.org>
      Cc: kbuild test robot <fengguang.wu@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3124eb16
    • Tejun Heo's avatar
      sysfs: prepare open path for unified regular / bin file handling · 49fe6047
      Tejun Heo authored
      
      
      sysfs bin file handling will be merged into the regular file support.
      This patch prepares the open path.
      
      This patch updates sysfs_open_file() such that it can handle both
      regular and bin files.
      
      This is a preparation and the new bin file path isn't used yet.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      49fe6047
    • Tejun Heo's avatar
      sysfs: copy bin mmap support from fs/sysfs/bin.c to fs/sysfs/file.c · 73d97146
      Tejun Heo authored
      
      
      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: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      73d97146
    • Tejun Heo's avatar
      sysfs: add sysfs_bin_read() · 2f0c6b75
      Tejun Heo authored
      
      
      sysfs bin file handling will be merged into the regular file support.
      This patch prepares the read path.
      
      Copy fs/sysfs/bin.c::read() to fs/sysfs/file.c and make it use
      sysfs_open_file instead of bin_buffer.  The function is identical copy
      except for the use of sysfs_open_file.
      
      The new function is added to sysfs_bin_operations.  This isn't used
      yet but will eventually replace fs/sysfs/bin.c.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2f0c6b75
    • Tejun Heo's avatar
      sysfs: prepare path write for unified regular / bin file handling · f9b9a621
      Tejun Heo authored
      
      
      sysfs bin file handling will be merged into the regular file support.
      This patch prepares the write path.
      
      bin file write is almost identical to regular file write except that
      the write length is capped by the inode size and @off is passed to the
      write method.  This patch adds bin file handling to sysfs_write_file()
      so that it can handle both regular and bin files.
      
      A new file_operations struct sysfs_bin_operations is added, which
      currently only hosts sysfs_write_file() and generic_file_llseek().
      This isn't used yet but will eventually replace fs/sysfs/bin.c.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f9b9a621
    • Tejun Heo's avatar
      sysfs: collapse fs/sysfs/bin.c::fill_read() into read() · 3ff65d3c
      Tejun Heo authored
      
      
      read() is simple enough and fill_read() being in a separate function
      doesn't add anything.  Let's collapse it into read().  This will make
      merging bin file handling with regular file.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3ff65d3c