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[I] = b;

}

}

return group_info;

out_undo_partial_alloc:

while (—I >= 0) {

free_page((unsigned long)group_info->blocks[I]);

}

kfree(group_info);

return NULL;

}

EXPORT_SYMBOL(groups_alloc);