[PATCH] hugetlb: fix race in set_max_huge_pages for multiple updaters of nr_huge_pages

[pandora-kernel.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 728e9bd..3e52df7 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -22,6 +22,10 @@ unsigned long max_huge_pages;
 static struct list_head hugepage_freelists[MAX_NUMNODES];
 static unsigned int nr_huge_pages_node[MAX_NUMNODES];
 static unsigned int free_huge_pages_node[MAX_NUMNODES];
+
+/*
+ * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
+ */
 static DEFINE_SPINLOCK(hugetlb_lock);
 
 static void enqueue_huge_page(struct page *page)
@@ -61,8 +65,10 @@ static struct page *alloc_fresh_huge_page(void)
                                        HUGETLB_PAGE_ORDER);
        nid = (nid + 1) % num_online_nodes();
        if (page) {
+               spin_lock(&hugetlb_lock);
                nr_huge_pages++;
                nr_huge_pages_node[page_to_nid(page)]++;
+               spin_unlock(&hugetlb_lock);
        }
        return page;
 }