Eric Lee / smarc-fsl-linux-kernel

05 Apr, 2016

1 commit

  • 09cbfeaf1   mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros ... Browse Code »

    PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
    ago with promise that one day it will be possible to implement page
    cache with bigger chunks than PAGE_SIZE.

    This promise never materialized. And unlikely will.

    We have many places where PAGE_CACHE_SIZE assumed to be equal to
    PAGE_SIZE. And it's constant source of confusion on whether
    PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
    especially on the border between fs and mm.

    Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
    breakage to be doable.

    Let's stop pretending that pages in page cache are special. They are
    not.

    The changes are pretty straight-forward:

    - << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ;

    - >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ;

    - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

    - page_cache_get() -> get_page();

    - page_cache_release() -> put_page();

    This patch contains automated changes generated with coccinelle using
    script below. For some reason, coccinelle doesn't patch header files.
    I've called spatch for them manually.

    The only adjustment after coccinelle is revert of changes to
    PAGE_CAHCE_ALIGN definition: we are going to drop it later.

    There are few places in the code where coccinelle didn't reach. I'll
    fix them manually in a separate patch. Comments and documentation also
    will be addressed with the separate patch.

    virtual patch

    @@
    expression E;
    @@
    - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
    + E

    @@
    expression E;
    @@
    - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
    + E

    @@
    @@
    - PAGE_CACHE_SHIFT
    + PAGE_SHIFT

    @@
    @@
    - PAGE_CACHE_SIZE
    + PAGE_SIZE

    @@
    @@
    - PAGE_CACHE_MASK
    + PAGE_MASK

    @@
    expression E;
    @@
    - PAGE_CACHE_ALIGN(E)
    + PAGE_ALIGN(E)

    @@
    expression E;
    @@
    - page_cache_get(E)
    + get_page(E)

    @@
    expression E;
    @@
    - page_cache_release(E)
    + put_page(E)

    Signed-off-by: Kirill A. Shutemov
    Acked-by: Michal Hocko
    Signed-off-by: Linus Torvalds

    Kirill A. Shutemov
     

20 Nov, 2013

2 commits

  • 846b730e9   Squashfs: Generalise paging handling in the decompressors ... Browse Code »

    Further generalise the decompressors by adding a page handler
    abstraction. This adds helpers to allow the decompressors
    to access and process the output buffers in an implementation
    independant manner.

    This allows different types of output buffer to be passed
    to the decompressors, with the implementation specific
    aspects handled at decompression time, but without the
    knowledge being held in the decompressor wrapper code.

    This will allow the decompressors to handle Squashfs
    cache buffers, and page cache pages.

    This patch adds the abstraction and an implementation for
    the caches.

    Signed-off-by: Phillip Lougher
    Reviewed-by: Minchan Kim

    Phillip Lougher
     
  • 9508c6b90   Squashfs: Refactor decompressor interface and code ... Browse Code »

    The decompressor interface and code was written from
    the point of view of single-threaded operation. In doing
    so it mixed a lot of single-threaded implementation specific
    aspects into the decompressor code and elsewhere which makes it
    difficult to seamlessly support multiple different decompressor
    implementations.

    This patch does the following:

    1. It removes compressor_options parsing from the decompressor
    init() function. This allows the decompressor init() function
    to be dynamically called to instantiate multiple decompressors,
    without the compressor options needing to be read and parsed each
    time.

    2. It moves threading and all sleeping operations out of the
    decompressors. In doing so, it makes the decompressors
    non-blocking wrappers which only deal with interfacing with
    the decompressor implementation.

    3. It splits decompressor.[ch] into decompressor generic functions
    in decompressor.[ch], and moves the single threaded
    decompressor implementation into decompressor_single.c.

    The result of this patch is Squashfs should now be able to
    support multiple decompressors by adding new decompressor_xxx.c
    files with specialised implementations of the functions in
    decompressor_single.c

    Signed-off-by: Phillip Lougher
    Reviewed-by: Minchan Kim

    Phillip Lougher
     

26 May, 2011

1 commit

23 Mar, 2011

1 commit

01 Mar, 2011

1 commit

  • b7fc0ff09   Squashfs: extend decompressor framework to handle compression options ... Browse Code »

    Extend decompressor framework to handle compression options stored in
    the filesystem. These options can be used by the relevant decompressor
    at initialisation time to over-ride defaults.

    The presence of compression options in the filesystem is indicated by
    the COMP_OPT filesystem flag. If present the data is read from the
    filesystem and passed to the decompressor init function. The decompressor
    init function signature has been extended to take this data.

    Also update the init function signature in the glib, lzo and xz
    decompressor wrappers.

    Signed-off-by: Phillip Lougher

    Phillip Lougher
     

26 Jan, 2011

1 commit

  • 3689456b4   squashfs: fix use of uninitialised variable in zlib & xz decompressors ... Browse Code »

    Fix potential use of uninitialised variable caused by recent
    decompressor code optimisations.

    In zlib_uncompress (zlib_wrapper.c) we have

    int zlib_err, zlib_init = 0;
    ...
    do {
    ...
    if (avail == 0) {
    offset = 0;
    put_bh(bh[k++]);
    continue;
    }
    ...
    zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
    ...
    } while (zlib_err == Z_OK);

    If continue is executed (avail == 0) then the while condition will be
    evaluated testing zlib_err, which is uninitialised first time around the
    loop.

    Fix this by getting rid of the 'if (avail == 0)' condition test, this
    edge condition should not be being handled in the decompressor code, and
    instead handle it generically in the caller code.

    Similarly for xz_wrapper.c.

    Incidentally, on most architectures (bar Mips and Parisc), no
    uninitialised variable warning is generated by gcc, this is because the
    while condition test on continue is optimised out and not performed
    (when executing continue zlib_err has not been changed since entering
    the loop, and logically if the while condition was true previously, then
    it's still true).

    Signed-off-by: Phillip Lougher
    Reported-by: Jesper Juhl
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Phillip Lougher
     

14 Jan, 2011

3 commits

23 Apr, 2010

1 commit

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
     

21 Jan, 2010

3 commits