mm, meminit: allow early_pfn_to_nid to be used during runtime

[firefly-linux-kernel-4.4.55.git] / mm / page_alloc.c

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ef19f22b2b7de1728fb4ed8d6451d29bb993a928..ea0e6a6e7a11f69365082ae271c79ca3009c7943 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -981,21 +981,21 @@ static void __init __free_pages_boot_core(struct page *page,
 
 #if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
        defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
-/* Only safe to use early in boot when initialisation is single-threaded */
+
 static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
 
 int __meminit early_pfn_to_nid(unsigned long pfn)
 {
+       static DEFINE_SPINLOCK(early_pfn_lock);
        int nid;
 
-       /* The system will behave unpredictably otherwise */
-       BUG_ON(system_state != SYSTEM_BOOTING);
-
+       spin_lock(&early_pfn_lock);
        nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
-       if (nid >= 0)
-               return nid;
-       /* just returns 0 */
-       return 0;
+       if (nid < 0)
+               nid = 0;
+       spin_unlock(&early_pfn_lock);
+
+       return nid;
 }
 #endif