Eric Lee / smarc-fsl-linux-kernel

04 Jan, 2012

1 commit

28 Jul, 2011

1 commit

  • 09570f914   proc: make struct proc_dir_entry::name a terminal array rather than a pointer ... Browse Code »

    Since __proc_create() appends the name it is given to the end of the PDE
    structure that it allocates, there isn't a need to store a name pointer.
    Instead we can just replace the name pointer with a terminal char array of
    _unspecified_ length. The compiler will simply append the string to statically
    defined variables of PDE type overlapping any hole at the end of the structure
    and, unlike specifying an explicitly _zero_ length array, won't give a warning
    if you try to statically initialise it with a string of more than zero length.

    Also, whilst we're at it:

    (1) Move namelen to end just prior to name and reduce it to a single byte
    (name shouldn't be longer than NAME_MAX).

    (2) Move pde_unload_lock two places further on so that if it's four bytes in
    size on a 64-bit machine, it won't cause an unused hole in the PDE struct.

    Signed-off-by: David Howells
    Signed-off-by: Alexey Dobriyan
    Signed-off-by: Linus Torvalds

    David Howells
     

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
     

05 Jan, 2009

1 commit

  • b4df2b92d   proc: stop using BKL ... Browse Code »

    There are four BKL users in proc: de_put(), proc_lookup_de(),
    proc_readdir_de(), proc_root_readdir(),

    1) de_put()
    -----------
    de_put() is classic atomic_dec_and_test() refcount wrapper -- no BKL
    needed. BKL doesn't matter to possible refcount leak as well.

    2) proc_lookup_de()
    -------------------
    Walking PDE list is protected by proc_subdir_lock(), proc_get_inode() is
    potentially blocking, all callers of proc_lookup_de() eventually end up
    from ->lookup hooks which is protected by directory's ->i_mutex -- BKL
    doesn't protect anything.

    3) proc_readdir_de()
    --------------------
    "." and ".." part doesn't need BKL, walking PDE list is under
    proc_subdir_lock, calling filldir callback is potentially blocking
    because it writes to luserspace. All proc_readdir_de() callers
    eventually come from ->readdir hook which is under directory's
    ->i_mutex -- BKL doesn't protect anything.

    4) proc_root_readdir_de()
    -------------------------
    proc_root_readdir_de is ->readdir hook, see (3).

    Since readdir hooks doesn't use BKL anymore, switch to
    generic_file_llseek, since it also takes directory's i_mutex.

    Signed-off-by: Alexey Dobriyan

    Alexey Dobriyan
     

23 Jul, 2008

1 commit

18 Jul, 2008

2 commits

02 May, 2008

1 commit

02 Apr, 2008

1 commit

28 Mar, 2008

1 commit

26 Mar, 2008

1 commit

08 Mar, 2008

1 commit

  • e9720acd7   [NET]: Make /proc/net a symlink on /proc/self/net (v3) ... Browse Code »

    Current /proc/net is done with so called "shadows", but current
    implementation is broken and has little chances to get fixed.

    The problem is that dentries subtree of /proc/net directory has
    fancy revalidation rules to make processes living in different
    net namespaces see different entries in /proc/net subtree, but
    currently, tasks see in the /proc/net subdir the contents of any
    other namespace, depending on who opened the file first.

    The proposed fix is to turn /proc/net into a symlink, which points
    to /proc/self/net, which in turn shows what previously was in
    /proc/net - the network-related info, from the net namespace the
    appropriate task lives in.

    # ls -l /proc/net
    lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net

    In other words - this behaves like /proc/mounts, but unlike
    "mounts", "net" is not a file, but a directory.

    Changes from v2:
    * Fixed discrepancy of /proc/net nlink count and selinux labeling
    screwup pointed out by Stephen.

    To get the correct nlink count the ->getattr callback for /proc/net
    is overridden to read one from the net->proc_net entry.

    To make selinux still work the net->proc_net entry is initialized
    properly, i.e. with the "net" name and the proc_net parent.

    Selinux fixes are
    Acked-by: Stephen Smalley

    Changes from v1:
    * Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.

    Signed-off-by: Pavel Emelyanov
    Acked-by: "Eric W. Biederman"
    Signed-off-by: David S. Miller

    Pavel Emelyanov
     

09 Feb, 2008

1 commit

  • 2d3a4e366   proc: fix ->open'less usage due to ->proc_fops flip ... Browse Code »

    Typical PDE creation code looks like:

    pde = create_proc_entry("foo", 0, NULL);
    if (pde)
    pde->proc_fops = &foo_proc_fops;

    Notice that PDE is first created, only then ->proc_fops is set up to
    final value. This is a problem because right after creation
    a) PDE is fully visible in /proc , and
    b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
    possible to ->read without ->open (see one class of oopses below).

    The fix is new API called proc_create() which makes sure ->proc_fops are
    set up before gluing PDE to main tree. Typical new code looks like:

    pde = proc_create("foo", 0, NULL, &foo_proc_fops);
    if (!pde)
    return -ENOMEM;

    Fix most networking users for a start.

    In the long run, create_proc_entry() for regular files will go.

    BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
    printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
    Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
    last sysfs file: /sys/block/sda/sda1/dev
    Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom

    Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
    EIP: 0060:[] EFLAGS: 00210002 CPU: 0
    EIP is at mutex_lock_nested+0x75/0x25d
    EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
    ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
    DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
    Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
    Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
    00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
    00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
    Call Trace:
    [] seq_read+0x24/0x28a
    [] seq_read+0x0/0x28a
    [] seq_read+0x24/0x28a
    [] seq_read+0x0/0x28a
    [] proc_reg_read+0x60/0x73
    [] proc_reg_read+0x0/0x73
    [] vfs_read+0x6c/0x8b
    [] sys_read+0x3c/0x63
    [] sysenter_past_esp+0x5f/0xa5
    [] destroy_inode+0x24/0x33
    =======================
    INFO: lockdep is turned off.
    Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
    EIP: [] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Alexey Dobriyan
    Cc: "Eric W. Biederman"
    Cc: Oleg Nesterov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alexey Dobriyan
     

29 Jan, 2008

2 commits

01 Dec, 2007

1 commit

  • 2b1e300a9   [NETNS]: Fix /proc/net breakage ... Browse Code »

    Well I clearly goofed when I added the initial network namespace support
    for /proc/net. Currently things work but there are odd details visible to
    user space, even when we have a single network namespace.

    Since we do not cache proc_dir_entry dentries at the moment we can just
    modify ->lookup to return a different directory inode depending on the
    network namespace of the process looking at /proc/net, replacing the
    current technique of using a magic and fragile follow_link method.

    To accomplish that this patch:
    - introduces a shadow_proc method to allow different dentries to
    be returned from proc_lookup.
    - Removes the old /proc/net follow_link magic
    - Fixes a weakness in our not caching of proc generic dentries.

    As shadow_proc uses a task struct to decided which dentry to return we can
    go back later and fix the proc generic caching without modifying any code
    that uses the shadow_proc method.

    Signed-off-by: Eric W. Biederman
    Cc: "Rafael J. Wysocki"
    Cc: Pavel Machek
    Cc: Pavel Emelyanov
    Cc: "David S. Miller"
    Cc: Ingo Molnar
    Signed-off-by: Andrew Morton
    Signed-off-by: Herbert Xu

    Eric W. Biederman
     

13 Nov, 2007

1 commit

07 Nov, 2007

1 commit

27 Oct, 2007

1 commit

  • 2b008b0a8   [NET]: Marking struct pernet_operations __net_initdata was inappropriate ... Browse Code »

    It is not safe to to place struct pernet_operations in a special section.
    We need struct pernet_operations to last until we call unregister_pernet_subsys.
    Which doesn't happen until module unload.

    So marking struct pernet_operations is a disaster for modules in two ways.
    - We discard it before we call the exit method it points to.
    - Because I keep struct pernet_operations on a linked list discarding
    it for compiled in code removes elements in the middle of a linked
    list and does horrible things for linked insert.

    So this looks safe assuming __exit_refok is not discarded
    for modules.

    Signed-off-by: Eric W. Biederman
    Signed-off-by: David S. Miller

    Eric W. Biederman
     

26 Oct, 2007

1 commit

11 Oct, 2007

4 commits

  • 4665079cb   [NETNS]: Move some code into __init section when CONFIG_NET_NS=n ... Browse Code »

    With the net namespaces many code leaved the __init section,
    thus making the kernel occupy more memory than it did before.
    Since we have a config option that prohibits the namespace
    creation, the functions that initialize/finalize some netns
    stuff are simply not needed and can be freed after the boot.

    Currently, this is almost not noticeable, since few calls
    are no longer in __init, but when the namespaces will be
    merged it will be possible to free more code. I propose to
    use the __net_init, __net_exit and __net_initdata "attributes"
    for functions/variables that are not used if the CONFIG_NET_NS
    is not set to save more space in memory.

    The exiting functions cannot just reside in the __exit section,
    as noticed by David, since the init section will have
    references on it and the compilation will fail due to modpost
    checks. These references can exist, since the init namespace
    never dies and the exit callbacks are never called. So I
    introduce the __exit_refok attribute just like it is already
    done with the __init_refok.

    Signed-off-by: Pavel Emelyanov
    Signed-off-by: David S. Miller

    Pavel Emelyanov
     
  • 077130c0c   [NET]: Fix race when opening a proc file while a network namespace is exiting. ... Browse Code »

    The problem: proc_net files remember which network namespace the are
    against but do not remember hold a reference count (as that would pin
    the network namespace). So we currently have a small window where
    the reference count on a network namespace may be incremented when opening
    a /proc file when it has already gone to zero.

    To fix this introduce maybe_get_net and get_proc_net.

    maybe_get_net increments the network namespace reference count only if it is
    greater then zero, ensuring we don't increment a reference count after it
    has gone to zero.

    get_proc_net handles all of the magic to go from a proc inode to the network
    namespace instance and call maybe_get_net on it.

    PROC_NET the old accessor is removed so that we don't get confused and use
    the wrong helper function.

    Then I fix up the callers to use get_proc_net and handle the case case
    where get_proc_net returns NULL. In that case I return -ENXIO because
    effectively the network namespace has already gone away so the files
    we are trying to access don't exist anymore.

    Signed-off-by: Eric W. Biederman
    Acked-by: Paul E. McKenney
    Signed-off-by: David S. Miller

    Eric W. Biederman
     
  • 36ac3135f   [NETNS]: Fix export symbols. ... Browse Code »

    Add the appropriate EXPORT_SYMBOLS for proc_net_create,
    proc_net_fops_create and proc_net_remove to fix errors when
    compiling allmodconfig

    Signed-off-by: Mark Nelson
    Acked-by: Benjamin Thery
    Signed-off-by: David S. Miller

    Daniel Lezcano
     
  • 3c12afe75   [NET]: Fix missed addition of fs/proc/proc_net.c ... Browse Code »

    My bad.

    Signed-off-by: David S. Miller

    David S. Miller