Commit-ID: e0891a9816316b5e05fd5b0453ffe9fd6a56f489 Gitweb: http://git.kernel.org/tip/e0891a9816316b5e05fd5b0453ffe9fd6a56f489 Author: David Howells <dhowells@xxxxxxxxxx> AuthorDate: Mon, 20 Feb 2012 22:39:18 +0000 Committer: H. Peter Anvin <hpa@xxxxxxxxx> CommitDate: Mon, 20 Feb 2012 14:46:55 -0800 bitops: Adjust the comment on get_order() to describe the size==0 case Adjust the comment on get_order() to note that the result of passing a size of 0 results in an undefined value. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Link: http://lkml.kernel.org/r/20120220223917.16199.9416.stgit@xxxxxxxxxxxxxxxxxxxxxx Acked-by: Arnd Bergmann <arnd@xxxxxxxx> Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx> --- include/asm-generic/getorder.h | 23 ++++++++++++++++++++++- 1 files changed, 22 insertions(+), 1 deletions(-) diff --git a/include/asm-generic/getorder.h b/include/asm-generic/getorder.h index 67e7245..76e9687 100644 --- a/include/asm-generic/getorder.h +++ b/include/asm-generic/getorder.h @@ -5,7 +5,28 @@ #include <linux/compiler.h> -/* Pure 2^n version of get_order */ +/** + * get_order - Determine the allocation order of a memory size + * @size: The size for which to get the order + * + * Determine the allocation order of a particular sized block of memory. This + * is on a logarithmic scale, where: + * + * 0 -> 2^0 * PAGE_SIZE and below + * 1 -> 2^1 * PAGE_SIZE to 2^0 * PAGE_SIZE + 1 + * 2 -> 2^2 * PAGE_SIZE to 2^1 * PAGE_SIZE + 1 + * 3 -> 2^3 * PAGE_SIZE to 2^2 * PAGE_SIZE + 1 + * 4 -> 2^4 * PAGE_SIZE to 2^3 * PAGE_SIZE + 1 + * ... + * + * The order returned is used to find the smallest allocation granule required + * to hold an object of the specified size. + * + * The result is undefined if the size is 0. + * + * This function may be used to initialise variables with compile time + * evaluations of constants. + */ static inline __attribute_const__ int get_order(unsigned long size) { int order; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html