Eric Lee / smarc-fsl-linux-kernel

30 Mar, 2010

1 commit

  • 5a0e3ad6a   include cleanup: Update gfp.h and slab.h includes to prepare for breaking implic… ... Browse Code »

    …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

14 Jan, 2010

1 commit

22 Apr, 2009

1 commit

  • 3c48f23ad   configfs: Fix Trivial Warning in fs/configfs/symlink.c ... Browse Code »

    I observed the following build warning with fs/configfs/symlink.c:

    fs/configfs/symlink.c: In function 'configfs_symlink':
    fs/configfs/symlink.c:138: warning: 'target_item' may be used uninitialized in this function

    Here is a small fix for this.

    Cc: Patrick Mochel
    Cc: Balbir Singh
    Cc: Sachin P Sant
    Signed-Off-By: Subrata Modak
    Signed-off-by: Joel Becker

    Subrata Modak
     

23 Oct, 2008

1 commit

01 Aug, 2008

3 commits

  • 2a109f2a4   [PATCH] configfs: Prevent userspace from creating new entries under attaching directories ... Browse Code »

    process 1: process 2:
    configfs_mkdir("A")
    attach_group("A")
    attach_item("A")
    d_instantiate("A")
    populate_groups("A")
    mutex_lock("A")
    attach_group("A/B")
    attach_item("A")
    d_instantiate("A/B")
    mkdir("A/B/C")
    do_path_lookup("A/B/C", LOOKUP_PARENT)
    ok
    lookup_create("A/B/C")
    mutex_lock("A/B")
    ok
    configfs_mkdir("A/B/C")
    ok
    attach_group("A/C")
    attach_item("A/C")
    d_instantiate("A/C")
    populate_groups("A/C")
    mutex_lock("A/C")
    attach_group("A/C/D")
    attach_item("A/C/D")
    failure
    mutex_unlock("A/C")
    detach_groups("A/C")
    nothing to do
    mkdir("A/C/E")
    do_path_lookup("A/C/E", LOOKUP_PARENT)
    ok
    lookup_create("A/C/E")
    mutex_lock("A/C")
    ok
    configfs_mkdir("A/C/E")
    ok
    detach_item("A/C")
    d_delete("A/C")
    mutex_unlock("A")
    detach_groups("A")
    mutex_lock("A/B")
    detach_group("A/B")
    detach_groups("A/B")
    nothing since no _default_ group
    detach_item("A/B")
    mutex_unlock("A/B")
    d_delete("A/B")
    detach_item("A")
    d_delete("A")

    Two bugs:

    1/ "A/B/C" and "A/C/E" are created, but never removed while their parent are
    removed in the end. The same could happen with symlink() instead of mkdir().

    2/ "A" and "A/C" inodes are not locked while detach_item() is called on them,
    which may probably confuse VFS.

    This commit fixes 1/, tagging new directories with CONFIGFS_USET_CREATING before
    building the inode and instantiating the dentry, and validating the whole
    group+default groups hierarchy in a second pass by clearing
    CONFIGFS_USET_CREATING.
    mkdir(), symlink(), lookup(), and dir_open() simply return -ENOENT if
    called in (or linking to) a directory tagged with CONFIGFS_USET_CREATING. This
    does not prevent userspace from calling stat() successfuly on such directories,
    but this prevents userspace from adding (children to | symlinking from/to |
    read/write attributes of | listing the contents of) not validated items. In
    other words, userspace will not interact with the subsystem on a new item until
    the new item creation completes correctly.
    It was first proposed to re-use CONFIGFS_USET_IN_MKDIR instead of a new
    flag CONFIGFS_USET_CREATING, but this generated conflicts when checking the
    target of a new symlink: a valid target directory in the middle of attaching
    a new user-created child item could be wrongly detected as being attached.

    2/ is fixed by next commit.

    Signed-off-by: Louis Rilling
    Signed-off-by: Joel Becker
    Signed-off-by: Mark Fasheh

    Louis Rilling
     
  • 9a73d78cd   [PATCH] configfs: Fix failing symlink() making rmdir() fail ... Browse Code »

    On a similar pattern as mkdir() vs rmdir(), a failing symlink() may make rmdir()
    fail for the symlink's parent and the symlink's target as well.

    failing symlink() making target's rmdir() fail:

    process 1: process 2:
    symlink("A/S" -> "B")
    allow_link()
    create_link()
    attach to "B" links list
    rmdir("B")
    detach_prep("B")
    error because of new link
    configfs_create_link("A", "S")
    error (eg -ENOMEM)

    failing symlink() making parent's rmdir() fail:

    process 1: process 2:
    symlink("A/D/S" -> "B")
    allow_link()
    create_link()
    attach to "B" links list
    configfs_create_link("A/D", "S")
    make_dirent("A/D", "S")
    rmdir("A")
    detach_prep("A")
    detach_prep("A/D")
    error because of "S"
    create("S")
    error (eg -ENOMEM)

    We cannot use the same solution as for mkdir() vs rmdir(), since rmdir() on the
    target cannot wait on the i_mutex of the new symlink's parent without risking a
    deadlock (with other symlink() or sys_rename()). Instead we define a global
    mutex protecting all configfs symlinks attachment, so that rmdir() can avoid the
    races above.

    Signed-off-by: Louis Rilling
    Signed-off-by: Joel Becker
    Signed-off-by: Mark Fasheh

    Louis Rilling
     
  • 4768e9b18   [PATCH] configfs: Fix symlink() to a removing item ... Browse Code »

    The rule for configfs symlinks is that symlinks always point to valid
    config_items, and prevent the target from being removed. However,
    configfs_symlink() only checks that it can grab a reference on the target item,
    without ensuring that it remains alive until the symlink is correctly attached.

    This patch makes configfs_symlink() fail whenever the target is being removed,
    using the CONFIGFS_USET_DROPPING flag set by configfs_detach_prep() and
    protected by configfs_dirent_lock.

    This patch introduces a similar (weird?) behavior as with mkdir failures making
    rmdir fail: if symlink() races with rmdir() of the parent directory (or its
    youngest user-created ancestor if parent is a default group) or rmdir() of the
    target directory, and then fails in configfs_create(), this can make the racing
    rmdir() fail despite the concerned directory having no user-created entry (resp.
    no symlink pointing to it or one of its default groups) in the end.
    This behavior is fixed in later patches.

    Signed-off-by: Louis Rilling
    Signed-off-by: Joel Becker
    Signed-off-by: Mark Fasheh

    Louis Rilling
     

15 Jul, 2008

3 commits

  • e75206517   configfs: call drop_link() to cleanup after create_link() failure ... Browse Code »

    When allow_link() succeeds but create_link() fails, the subsystem is not
    informed of the failure.

    This patch fixes this by calling drop_link() on create_link() failures.

    Signed-off-by: Louis Rilling
    Signed-off-by: Joel Becker

    Louis Rilling
     
  • 5301a77da   configfs: Protect configfs_dirent s_links list mutations ... Browse Code »

    Symlinks to a config_item are listed under its configfs_dirent s_links, but the
    list mutations are not protected by any common lock.

    This patch uses the configfs_dirent_lock spinlock to add the necessary
    protection.

    Note: we should also protect the list_empty() test in configfs_detach_prep() but
    1/ the lock should not be released immediately because nothing would prevent the
    list from being filled after a successful list_empty() test, making the problem
    tricky,
    2/ this will be solved by the rmdir() vs rename() deadlock bugfix.

    Signed-off-by: Louis Rilling
    Signed-off-by: Joel Becker

    Louis Rilling
     
  • 6f6107640   configfs: Introduce configfs_dirent_lock ... Browse Code »

    This patch introduces configfs_dirent_lock spinlock to protect configfs_dirent
    traversals against linkage mutations (add/del/move). This will allow
    configfs_detach_prep() to avoid locking i_mutexes.

    Locking rules for configfs_dirent linkage mutations are the same plus the
    requirement of taking configfs_dirent_lock. For configfs_dirent walking, one can
    either take appropriate i_mutex as before, or take configfs_dirent_lock.

    The spinlock could actually be a mutex, but the critical sections are either
    O(1) or should not be too long (default groups walking in last patch).

    ChangeLog:
    - Clarify the comment on configfs_dirent_lock usage
    - Move sd->s_element init before linking the new dirent
    - In lseek(), do not release configfs_dirent_lock before the dirent is
    relinked.

    Signed-off-by: Louis Rilling
    Signed-off-by: Joel Becker

    Louis Rilling
     

30 Apr, 2008

1 commit

15 Feb, 2008

2 commits

  • 1d957f9bf   Introduce path_put() ... Browse Code »

    * Add path_put() functions for releasing a reference to the dentry and
    vfsmount of a struct path in the right order

    * Switch from path_release(nd) to path_put(&nd->path)

    * Rename dput_path() to path_put_conditional()

    [akpm@linux-foundation.org: fix cifs]
    Signed-off-by: Jan Blunck
    Signed-off-by: Andreas Gruenbacher
    Acked-by: Christoph Hellwig
    Cc:
    Cc: Al Viro
    Cc: Steven French
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jan Blunck
     
  • 4ac913785   Embed a struct path into struct nameidata instead of nd->{dentry,mnt} ... Browse Code »

    This is the central patch of a cleanup series. In most cases there is no good
    reason why someone would want to use a dentry for itself. This series reflects
    that fact and embeds a struct path into nameidata.

    Together with the other patches of this series
    - it enforced the correct order of getting/releasing the reference count on
    pairs
    - it prepares the VFS for stacking support since it is essential to have a
    struct path in every place where the stack can be traversed
    - it reduces the overall code size:

    without patch series:
    text data bss dec hex filename
    5321639 858418 715768 6895825 6938d1 vmlinux

    with patch series:
    text data bss dec hex filename
    5320026 858418 715768 6894212 693284 vmlinux

    This patch:

    Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere.

    [akpm@linux-foundation.org: coding-style fixes]
    [akpm@linux-foundation.org: fix cifs]
    [akpm@linux-foundation.org: fix smack]
    Signed-off-by: Jan Blunck
    Signed-off-by: Andreas Gruenbacher
    Acked-by: Christoph Hellwig
    Cc: Al Viro
    Cc: Casey Schaufler
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jan Blunck
     

13 Feb, 2007

1 commit

  • 754661f14   [PATCH] mark struct inode_operations const 1 ... Browse Code »

    Many struct inode_operations in the kernel can be "const". Marking them const
    moves these to the .rodata section, which avoids false sharing with potential
    dirty data. In addition it'll catch accidental writes at compile time to
    these shared resources.

    Signed-off-by: Arjan van de Ven
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Arjan van de Ven
     

30 Jun, 2006

1 commit

04 Feb, 2006

2 commits

04 Jan, 2006

1 commit