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    Subject[patch 26/29] arch/m68k/mm/motorola.c: Eliminate NULL test and memset after alloc_bootmem
    From: Julia Lawall <julia@diku.dk>

    As noted by Akinobu Mita in patch b1fceac2b9e04d278316b2faddf276015fc06e3b,
    alloc_bootmem and related functions never return NULL and always return a
    zeroed region of memory. Thus a NULL test or memset after calls to these
    functions is unnecessary.

    This was fixed using the following semantic patch.
    (http://www.emn.fr/x-info/coccinelle/)

    // <smpl>
    @@
    expression E;
    statement S;
    @@

    E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
    .. when != E
    (
    - BUG_ON (E == NULL);
    |
    - if (E == NULL) S
    )

    @@
    expression E,E1;
    @@

    E = \(alloc_bootmem\|alloc_bootmem_low\|alloc_bootmem_pages\|alloc_bootmem_low_pages\)(...)
    .. when != E
    - memset(E,0,E1);
    // </smpl>

    Signed-off-by: Julia Lawall <julia@diku.dk>
    Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
    ---
    arch/m68k/mm/motorola.c | 1 -
    1 file changed, 1 deletion(-)

    --- a/arch/m68k/mm/motorola.c
    +++ b/arch/m68k/mm/motorola.c
    @@ -285,7 +285,6 @@ void __init paging_init(void)
    * to a couple of allocated pages
    */
    empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
    - memset(empty_zero_page, 0, PAGE_SIZE);

    /*
    * Set up SFC/DFC registers
    --
    Gr{oetje,eeting}s,
    Geert

    --
    Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

    In personal conversations with technical people, I call myself a hacker. But
    when I'm talking to journalists I just say "programmer" or something like that.
    -- Linus Torvalds



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