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author | Roland Dreier <rdreier@cisco.com> | 2010-01-15 17:01:22 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-01-16 12:15:39 -0800 |
commit | cc8ef6eb21e964b1c5eb97b2d0e8ac9893e1bf86 (patch) | |
tree | c30758f4f980a71acd662f55006af80c8a11b27f /mm | |
parent | d2dbe08ddceb4ba2b274abb84326d7e69d454e5c (diff) | |
download | kernel_goldelico_gta04-cc8ef6eb21e964b1c5eb97b2d0e8ac9893e1bf86.zip kernel_goldelico_gta04-cc8ef6eb21e964b1c5eb97b2d0e8ac9893e1bf86.tar.gz kernel_goldelico_gta04-cc8ef6eb21e964b1c5eb97b2d0e8ac9893e1bf86.tar.bz2 |
kernel.h: add BUILD_BUG_ON_NOT_POWER_OF_2()
Add BUILD_BUG_ON_NOT_POWER_OF_2()
When code relies on a constant being a power of 2:
#define FOO 512 /* must be a power of 2 */
it would be nice to be able to do:
BUILD_BUG_ON(!is_power_of_2(FOO));
However applying an inline function does not result in a compile-time
constant that can be used with BUILD_BUG_ON(), so trying that gives
results in:
error: bit-field '<anonymous>' width not an integer constant
As suggested by akpm, rather than monkeying around with is_power_of_2()
and risking gcc warts about constant expressions, just create a macro
BUILD_BUG_ON_NOT_POWER_OF_2() to encapsulate this common requirement.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: David Dillow <dave@thedillows.org>
Cc: "Robert P. J. Day" <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
0 files changed, 0 insertions, 0 deletions