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    SubjectRe: [PATCH 1/2] ext4: use little-endian bitops directly
    2011/5/31 Ted Ts'o <>:
    > On Mon, May 30, 2011 at 08:49:43AM -0600, Andreas Dilger wrote:
    >> On 2011-05-30, at 7:49 AM, Akinobu Mita <> wrote:
    >> > s/ext4_set_bit/__test_and_set_bit_le/
    >> > s/ext4_clear_bit/__test_and_clear_bit_le/
    >> > s/ext4_test_bit/test_bit_le/
    >> > s/ext4_find_first_zero_bit/find_first_zero_bit_le/
    >> > s/ext4_find_next_zero_bit/find_next_zero_bit_le/
    >> > s/ext4_find_next_bit/find_next_bit_le/
    >> I'm not souch in favor of making this change. One reason is the need
    >> for inconsistent test_bit_le() vs __test_and_set_bit_le()
    >> functions. I think this will make it more difficult to get the
    >> correct bit operations (I for one do not know the difference between
    >> the normal and __ versions without looking each time).
    > More to the point, what's the benefit of making this change?

    The main purpose is patch 2/2 that replaces __test_and_{set,clear}_bit_le()
    with __{set,clear}_bit_le(). But there is no ext4_*_bit() macros for
    __{set,clear}_bit_le(). So I convert to use *_bit_le() directly in this
    patch instead of introducing another ext4_*_bit() macros.

    I don't insist on removing these macros for this purpose against the
    developper's will. There is an alternative suggestion that changes
    ext4_*_bit() macros like below.

    #define ext4_test_and_set_bit __test_and_set_bit_le
    #define ext4_set_bit __set_bit_le
    #define ext4_set_bit_atomic ext2_set_bit_atomic
    #define ext4_test_and_clear_bit __test_and_clear_bit_le
    #define ext4_clear_bit __clear_bit_le
    #define ext4_clear_bit_atomic ext2_clear_bit_atomic
    #define ext4_test_bit test_bit_le
    #define ext4_find_first_zero_bit find_first_zero_bit_le
    #define ext4_find_next_zero_bit find_next_zero_bit_le
    #define ext4_find_next_bit find_next_bit_le

    By this chage, ext4_test_and_{set,clear}_bit are added and
    ext4_{set,clear}_bit are changed.

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      Last update: 2011-05-30 18:23    [W:0.020 / U:9.132 seconds]
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