1. 06 Oct, 2013 11 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: use seq_file when reading regular files · 13c589d5
      Tejun Heo authored
      
      
      sysfs read path implements its own buffering scheme between userland
      and kernel callbacks, which essentially is a degenerate duplicate of
      seq_file.  This patch replaces the custom read buffering
      implementation in sysfs with seq_file.
      
      While the amount of code reduction is small, this reduces low level
      hairiness and enables future development of a new versatile API based
      on seq_file so that sysfs features can be shared with other
      subsystems.
      
      As write path was already converted to not use sysfs_open_file->page,
      this patch makes ->page and ->count unused and removes them.
      
      Userland behavior remains the same except for some extreme corner
      cases - e.g. sysfs will now regenerate the content each time a file is
      read after a non-contiguous seek whereas the original code would keep
      using the same content.  While this is a userland visible behavior
      change, it is extremely unlikely to be noticeable and brings sysfs
      behavior closer to that of procfs.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Kay Sievers <kay@vrfy.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      13c589d5
    • Tejun Heo's avatar
      sysfs: use transient write buffer · 8ef445f0
      Tejun Heo authored
      
      
      There isn't much to be gained by keeping around kernel buffer while a
      file is open especially as the read path planned to be converted to
      use seq_file and won't use the buffer.  This patch makes
      sysfs_write_file() use per-write transient buffer instead of
      sysfs_open_file->page.
      
      This simplifies the write path, enables removing sysfs_open_file->page
      once read path is updated and will help merging bin file write path
      which already requires the use of a transient buffer due to a locking
      order issue.
      
      As the function comments of flush_write_buffer() and
      sysfs_write_buffer() are being updated anyway, reformat them so that
      they're more conventional.
      
      v2: Use min_t() instead of min() in sysfs_write_file() to avoid build
          warning on arm.  Reported by build test robot.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: kbuild test robot <fengguang.wu@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      8ef445f0
    • Tejun Heo's avatar
      sysfs: add sysfs_open_file->sd and ->file · bcafe4ee
      Tejun Heo authored
      
      
      sysfs will be converted to use seq_file for read path, which will make
      it difficult to pass around multiple pointers directly.  This patch
      adds sysfs_open_file->sd and ->file so that we can reach all the
      necessary data structures from sysfs_open_file.
      
      flush_write_buffer() is updated to drop @dentry which was used to
      discover the sysfs_dirent as it's now available through
      sysfs_open_file->sd.
      
      This patch doesn't cause any behavior difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      bcafe4ee
    • Tejun Heo's avatar
      sysfs: rename sysfs_buffer to sysfs_open_file · 58282d8d
      Tejun Heo authored
      
      
      sysfs read path will be converted to use seq_file which will handle
      buffering making sysfs_buffer a misnomer.  Rename sysfs_buffer to
      sysfs_open_file, and sysfs_open_dirent->buffers to ->files.
      
      This path is pure rename.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      58282d8d
    • Tejun Heo's avatar
      sysfs: add sysfs_open_file_mutex · c75ec764
      Tejun Heo authored
      
      
      Add a separate mutex to protect sysfs_open_dirent->buffers list.  This
      will allow performing sleepable operations while traversing
      sysfs_buffers, which will be renamed to sysfs_open_file.
      
      Note that currently sysfs_open_dirent->buffers list isn't being used
      for anything and this patch doesn't make any functional difference.
      It will be used to merge regular and bin file supports.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c75ec764
    • Tejun Heo's avatar
      sysfs: remove sysfs_buffer->ops · 375b611e
      Tejun Heo authored
      
      
      Currently, sysfs_ops is fetched during sysfs_open_file() and cached in
      sysfs_buffer->ops to be used while the file is open.  This patch
      removes the caching and makes each operation directly fetch sysfs_ops.
      
      This patch doesn't introduce any behavior difference and is to prepare
      for merging regular and bin file supports.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      375b611e
  2. 05 Oct, 2013 2 commits
    • Tejun Heo's avatar
      sysfs: remove sysfs_buffer->needs_read_fill · aea585ef
      Tejun Heo authored
      
      
      ->needs_read_fill is used to implement the following behaviors.
      
      1. Ensure buffer filling on the first read.
      2. Force buffer filling after a write.
      3. Force buffer filling after a successful poll.
      
      However, #2 and #3 don't really work as sysfs doesn't reset file
      position.  While the read buffer would be refilled, the next read
      would continue from the position after the last read or write,
      requiring an explicit seek to the start for it to be useful, which
      makes ->needs_read_fill superflous as read buffer is always refilled
      if f_pos == 0.
      
      Update sysfs_read_file() to test buffer->page for #1 instead and
      remove ->needs_read_fill.  While this changes behavior in extreme
      corner cases - e.g. re-reading a sysfs file after seeking to non-zero
      position after a write or poll, it's highly unlikely to lead to actual
      breakage.  This change is to prepare for using seq_file in the read
      path.
      
      While at it, reformat a comment in fill_write_buffer().
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Kay Sievers <kay@vrfy.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      aea585ef
    • Tejun Heo's avatar
      89e51dab
  3. 03 Oct, 2013 1 commit
    • Tejun Heo's avatar
      sysfs: remove sysfs_addrm_cxt->parent_sd · d69ac5a0
      Tejun Heo authored
      
      
      sysfs_addrm_start/finish() enclose sysfs_dirent additions and
      deletions and sysfs_addrm_cxt is used to record information necessary
      to finish the operations.  Currently, sysfs_addrm_start() takes
      @parent_sd, records it in sysfs_addrm_cxt, and assumes that all
      operations in the block are performed under that @parent_sd.
      
      This assumption has been fine until now but we want to make some
      operations behave recursively and, while having @parent_sd recorded in
      sysfs_addrm_cxt doesn't necessarily prevents that, it becomes
      confusing.
      
      This patch removes sysfs_addrm_cxt->parent_sd and makes
      sysfs_add_one() take an explicit @parent_sd parameter.  Note that
      sysfs_remove_one() doesn't need the extra argument as its parent is
      always known from the target @sd.
      
      While at it, add __acquires/releases() notations to
      sysfs_addrm_start/finish() respectively.
      
      This patch doesn't make any functional difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d69ac5a0
  4. 26 Sep, 2013 3 commits
    • Tejun Heo's avatar
      sysfs: @name comes before @ns · cfec0bc8
      Tejun Heo authored
      
      
      Some internal sysfs functions which take explicit namespace argument
      are weird in that they place the optional @ns in front of @name which
      is contrary to the established convention.  This is confusing and
      error-prone especially as @ns and @name may be interchanged without
      causing compilation warning.
      
      Swap the positions of @name and @ns in the following internal
      functions.
      
       sysfs_find_dirent()
       sysfs_rename()
       sysfs_hash_and_remove()
       sysfs_name_hash()
       sysfs_name_compare()
       create_dir()
      
      This patch doesn't introduce any functional changes.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Eric W. Biederman <ebiederm@xmission.com>
      Cc: Kay Sievers <kay@vrfy.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      cfec0bc8
    • Tejun Heo's avatar
      sysfs: clean up sysfs_get_dirent() · 388975cc
      Tejun Heo authored
      
      
      The pre-existing sysfs interfaces which take explicit namespace
      argument are weird in that they place the optional @ns in front of
      @name which is contrary to the established convention.  For example,
      we end up forcing vast majority of sysfs_get_dirent() users to do
      sysfs_get_dirent(parent, NULL, name), which is silly and error-prone
      especially as @ns and @name may be interchanged without causing
      compilation warning.
      
      This renames sysfs_get_dirent() to sysfs_get_dirent_ns() and swap the
      positions of @name and @ns, and sysfs_get_dirent() is now a wrapper
      around sysfs_get_dirent_ns().  This makes confusions a lot less
      likely.
      
      There are other interfaces which take @ns before @name.  They'll be
      updated by following patches.
      
      This patch doesn't introduce any functional changes.
      
      v2: EXPORT_SYMBOL_GPL() wasn't updated leading to undefined symbol
          error on module builds.  Reported by build test robot.  Fixed.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Eric W. Biederman <ebiederm@xmission.com>
      Cc: Kay Sievers <kay@vrfy.org>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      388975cc
    • Tejun Heo's avatar
      sysfs: make attr namespace interface less convoluted · 58292cbe
      Tejun Heo authored
      
      
      sysfs ns (namespace) implementation became more convoluted than
      necessary while trying to hide ns information from visible interface.
      The relatively recent attr ns support is a good example.
      
      * attr ns tag is determined by sysfs_ops->namespace() callback while
        dir tag is determined by kobj_type->namespace().  The placement is
        arbitrary.
      
      * Instead of performing operations with explicit ns tag, the namespace
        callback is routed through sysfs_attr_ns(), sysfs_ops->namespace(),
        class_attr_namespace(), class_attr->namespace().  It's not simpler
        in any sense.  The only thing this convolution does is traversing
        the whole stack backwards.
      
      The namespace callbacks are unncessary because the operations involved
      are inherently synchronous.  The information can be provided in in
      straight-forward top-down direction and reversing that direction is
      unnecessary and against basic design principles.
      
      This backward interface is unnecessarily convoluted and hinders
      properly separating out sysfs from driver model / kobject for proper
      layering.  This patch updates attr ns support such that
      
      * sysfs_ops->namespace() and class_attr->namespace() are dropped.
      
      * sysfs_{create|remove}_file_ns(), which take explicit @ns param, are
        added and sysfs_{create|remove}_file() are now simple wrappers
        around the ns aware functions.
      
      * ns handling is dropped from sysfs_chmod_file().  Nobody uses it at
        this point.  sysfs_chmod_file_ns() can be added later if necessary.
      
      * Explicit @ns is propagated through class_{create|remove}_file_ns()
        and netdev_class_{create|remove}_file_ns().
      
      * driver/net/bonding which is currently the only user of attr
        namespace is updated to use netdev_class_{create|remove}_file_ns()
        with @bh->net as the ns tag instead of using the namespace callback.
      
      This patch should be an equivalent conversion without any functional
      difference.  It makes the code easier to follow, reduces lines of code
      a bit and helps proper separation and layering.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Eric W. Biederman <ebiederm@xmission.com>
      Cc: Kay Sievers <kay@vrfy.org>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      58292cbe
  5. 21 Aug, 2013 6 commits
  6. 07 Jun, 2013 1 commit
  7. 17 Jan, 2013 2 commits
  8. 27 Nov, 2012 1 commit
  9. 24 Jan, 2012 1 commit
    • Eric W. Biederman's avatar
      sysfs: Complain bitterly about attempts to remove files from nonexistent directories. · ce597919
      Eric W. Biederman authored
      
      
      Recently an OOPS was observed from the usb serial io_ti driver when it tried to remove
      sysfs directories.  Upon investigation it turns out this driver was always buggy
      and that a recent sysfs change had stopped guarding itself against removing attributes
      from sysfs directories that had already been removed. :(
      
      Historically we have been silent about attempting to files from nonexistent sysfs
      directories and have politely returned error codes.  That has resulted in people writing
      broken code that ignores the error codes.
      
      Issue a kernel WARNING and a stack backtrace to make it clear in no uncertain
      terms that abusing sysfs is not ok, and the callers need to fix their code.
      
      This change transforms the io_ti OOPS into a more comprehensible error message
      and stack backtrace.
      Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      Reported-by: default avatarWolfgang Frisch <wfpub@roembden.net>
      Cc: stable <stable@vger.kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      ce597919
  10. 04 Jan, 2012 2 commits
  11. 19 Oct, 2011 2 commits
    • Eric W. Biederman's avatar
      sysfs: Reject with a warning invalid uses of tagged directories. · 903e21e2
      Eric W. Biederman authored
      
      
      sysfs is a core piece of ifrastructure that many people use and
      few people have all of the rules in their head on how to use
      it correctly.  Add warnings for people using tagged directories
      improperly to that any misuses can be caught and diagnosed quickly.
      
      A single inexpensive test in sysfs_find_dirent is almost sufficient
      to catch all possible misuses.  An additional warning is needed
      in sysfs_add_dirent so that we actually fail when attempting to
      add an untagged dirent in a tagged directory.
      Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      903e21e2
    • Eric W. Biederman's avatar
      sysfs: Implement support for tagged files in sysfs. · 487505c2
      Eric W. Biederman authored
      
      
      Looking up files in sysfs is hard to understand and analyize because we
      currently allow placing untagged files in tagged directories.  In the
      implementation of that we have two subtly different meanings of NULL.
      NULL meaning there is no tag on a directory entry and NULL meaning
      we don't care which namespace the lookup is performed for.  This
      multiple uses of NULL have resulted in subtle bugs (since fixed)
      in the code.
      
      Currently it is only the bonding driver that needs to have an untagged
      file in a tagged directory.
      
      To untagle this mess I am adding support for tagged files to sysfs.
      Modifying the bonding driver to implement bonding_masters as a tagged
      file.  Registering bonding_masters once for each network namespace.
      Then I am removing support for untagged entries in tagged sysfs
      directories.
      
      Resulting in code that is much easier to reason about.
      Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      487505c2
  12. 13 May, 2011 1 commit
  13. 04 Sep, 2010 1 commit
  14. 05 Aug, 2010 1 commit
  15. 21 May, 2010 1 commit
    • Eric W. Biederman's avatar
      sysfs: Implement sysfs tagged directory support. · 3ff195b0
      Eric W. Biederman authored
      
      
      The problem.  When implementing a network namespace I need to be able
      to have multiple network devices with the same name.  Currently this
      is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and
      potentially a few other directories of the form /sys/ ... /net/*.
      
      What this patch does is to add an additional tag field to the
      sysfs dirent structure.  For directories that should show different
      contents depending on the context such as /sys/class/net/, and
      /sys/devices/virtual/net/ this tag field is used to specify the
      context in which those directories should be visible.  Effectively
      this is the same as creating multiple distinct directories with
      the same name but internally to sysfs the result is nicer.
      
      I am calling the concept of a single directory that looks like multiple
      directories all at the same path in the filesystem tagged directories.
      
      For the networking namespace the set of directories whose contents I need
      to filter with tags can depend on the presence or absence of hotplug
      hardware or which modules are currently loaded.  Which means I need
      a simple race free way to setup those directories as tagged.
      
      To achieve a reace free design all tagged directories are created
      and managed by sysfs itself.
      
      Users of this interface:
      - define a type in the sysfs_tag_type enumeration.
      - call sysfs_register_ns_types with the type and it's operations
      - sysfs_exit_ns when an individual tag is no longer valid
      
      - Implement mount_ns() which returns the ns of the calling process
        so we can attach it to a sysfs superblock.
      - Implement ktype.namespace() which returns the ns of a syfs kobject.
      
      Everything else is left up to sysfs and the driver layer.
      
      For the network namespace mount_ns and namespace() are essentially
      one line functions, and look to remain that.
      
      Tags are currently represented a const void * pointers as that is
      both generic, prevides enough information for equality comparisons,
      and is trivial to create for current users, as it is just the
      existing namespace pointer.
      
      The work needed in sysfs is more extensive.  At each directory
      or symlink creating I need to check if the directory it is being
      created in is a tagged directory and if so generate the appropriate
      tag to place on the sysfs_dirent.  Likewise at each symlink or
      directory removal I need to check if the sysfs directory it is
      being removed from is a tagged directory and if so figure out
      which tag goes along with the name I am deleting.
      
      Currently only directories which hold kobjects, and
      symlinks are supported.  There is not enough information
      in the current file attribute interfaces to give us anything
      to discriminate on which makes it useless, and there are
      no potential users which makes it an uninteresting problem
      to solve.
      Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      Signed-off-by: default avatarBenjamin Thery <benjamin.thery@bull.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      3ff195b0
  16. 08 Mar, 2010 4 commits