[PATCH] mm/hugetlb: Get rid of NODEMASK_ALLOC

[Oscar Salvador]

NODEMASK_ALLOC is used to allocate a nodemask bitmap, ant it does it by
first determining whether it should be allocated in the stack or dinamically
depending on NODES_SHIFT.
Right now, it goes the dynamic path whenever the nodemask_t is above 32
bytes.

Although we could bump it to a reasonable value, the largest a nodemask_t
can get is 128 bytes, so since __nr_hugepages_store_common is called from
a rather shore stack we can just get rid of the NODEMASK_ALLOC call here.

This reduces some code churn and complexity.

Signed-off-by: Oscar Salvador <osalva...@suse.de>
---
 mm/hugetlb.c | 36 +++++++++++-------------------------
 1 file changed, 11 insertions(+), 25 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f79ae4e42159..9cb2f91af897 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2447,44 +2447,30 @@ static ssize_t __nr_hugepages_store_common(bool 
obey_mempolicy,
                                           unsigned long count, size_t len)
 {
        int err;
-       NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
+       nodemask_t nodes_allowed, *n_mask;
 
-       if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) {
-               err = -EINVAL;
-               goto out;
-       }
+       if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
+               return -EINVAL;
 
        if (nid == NUMA_NO_NODE) {
                /*
                 * global hstate attribute
                 */
                if (!(obey_mempolicy &&
-                               init_nodemask_of_mempolicy(nodes_allowed))) {
-                       NODEMASK_FREE(nodes_allowed);
-                       nodes_allowed = &node_states[N_MEMORY];
-               }
-       } else if (nodes_allowed) {
+                               init_nodemask_of_mempolicy(&nodes_allowed)))
+                       n_mask = &node_states[N_MEMORY];
+               else
+                       n_mask = &nodes_allowed;
+       } else {
                /*
                 * Node specific request.  count adjustment happens in
                 * set_max_huge_pages() after acquiring hugetlb_lock.
                 */
-               init_nodemask_of_node(nodes_allowed, nid);
-       } else {
-               /*
-                * Node specific request, but we could not allocate the few
-                * words required for a node mask.  We are unlikely to hit
-                * this condition.  Since we can not pass down the appropriate
-                * node mask, just return ENOMEM.
-                */
-               err = -ENOMEM;
-               goto out;
+               init_nodemask_of_node(&nodes_allowed, nid);
+               n_mask = &nodes_allowed;
        }
 
-       err = set_max_huge_pages(h, count, nid, nodes_allowed);
-
-out:
-       if (nodes_allowed != &node_states[N_MEMORY])
-               NODEMASK_FREE(nodes_allowed);
+       err = set_max_huge_pages(h, count, nid, n_mask);
 
        return err ? err : len;
 }
-- 
2.13.7