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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@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rasmus Villemoes 2017-07-10 15:51:17 -07:00 committed by Linus Torvalds
parent 9dcdcea114
commit b7b2562f72
1 changed files with 11 additions and 24 deletions
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35
kernel/groups.c
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@ -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_info *group_info,
return 0;
}
/* a simple Shell sort */
static int gid_cmp(const void *_a, const void *_b)
{
kgid_t a = *(kgid_t *)_a;
kgid_t b = *(kgid_t *)_b;
return gid_gt(a, b) - gid_lt(a, b);
}
static void groups_sort(struct group_info *group_info)
{
int base, max, stride;
int gidsetsize = group_info->ngroups;
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;
}
sort(group_info->gid, group_info->ngroups, sizeof(*group_info->gid),
gid_cmp, NULL);
}
/* a simple bsearch */