From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> Subject: kernel/groups.c: use sort library function setgroups is not exactly a hot path, so we might as well use the library function instead of open-coding the sorting. Saves ~150 bytes. Link: http://lkml.kernel.org/r/1497301378-22739-1-git-send-email-linux@xxxxxxxxxxxxxxxxxx Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/groups.c | 35 +++++++++++------------------------ 1 file changed, 11 insertions(+), 24 deletions(-) diff -puN kernel/groups.c~kernel-groupsc-use-sort-library-function kernel/groups.c --- a/kernel/groups.c~kernel-groupsc-use-sort-library-function +++ a/kernel/groups.c @@ -5,6 +5,7 @@ #include <linux/export.h> #include <linux/slab.h> #include <linux/security.h> +#include <linux/sort.h> #include <linux/syscalls.h> #include <linux/user_namespace.h> #include <linux/vmalloc.h> @@ -76,32 +77,18 @@ static int groups_from_user(struct group return 0; } -/* a simple Shell sort */ -static void groups_sort(struct group_info *group_info) +static int gid_cmp(const void *_a, const void *_b) { - int base, max, stride; - int gidsetsize = group_info->ngroups; + kgid_t a = *(kgid_t *)_a; + kgid_t b = *(kgid_t *)_b; - for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1) - ; /* nothing */ - stride /= 3; - - while (stride) { - max = gidsetsize - stride; - for (base = 0; base < max; base++) { - int left = base; - int right = left + stride; - kgid_t tmp = group_info->gid[right]; - - while (left >= 0 && gid_gt(group_info->gid[left], tmp)) { - group_info->gid[right] = group_info->gid[left]; - right = left; - left -= stride; - } - group_info->gid[right] = tmp; - } - stride /= 3; - } + return gid_gt(a, b) - gid_lt(a, b); +} + +static void groups_sort(struct group_info *group_info) +{ + sort(group_info->gid, group_info->ngroups, sizeof(*group_info->gid), + gid_cmp, NULL); } /* a simple bsearch */ _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
