Its here https://psteamcommunity.yuanyoumao.com/tradeoffer/new/?partner=87492014&token=cH5NT3Az
struct group_info init_groups = { .usage = ATOMIC_INIT(2) };

struct group_info *groups_alloc(int gidsetsize){
struct group_info *group_info;
int nblocks;
int i;


nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
/* Make sure we always allocate at least one indirect block pointer */
nblocks = nblocks ? : 1;
group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
if (!group_info)
return NULL;

group_info->ngroups = gidsetsize;
group_info->nblocks = nblocks;
atomic_set(&group_info->usage, 1);

if (gidsetsize <= NGROUPS_SMALL)
group_info->blocks[0] = group_info->small_block;
else {
for (i = 0; i < nblocks; i++) {
gid_t *b;
b = (void *)__get_free_page(GFP_USER);
if (!b)
goto out_undo_partial_alloc;
group_info->blocks = b;
}
}
return group_info;


out_undo_partial_alloc:

while (--i >= 0) {

free_page((unsigned long)group_info->blocks );

}

kfree(group_info);

return NULL;

}



EXPORT_SYMBOL(groups_alloc);



void groups_free(struct group_info *group_info)

{

if (group_info->blocks[0] != group_info->small_block) {

int i;

for (i = 0; i < group_info->nblocks; i++)

free_page((unsigned long)group_info->blocks );

}

kfree(group_info);

}



EXPORT_SYMBOL(groups_free);