mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case

[linux.git] / mm / sparse.c

diff --git a/mm/sparse.c b/mm/sparse.c
index 596b2a45b100507e95d7c7694698c36283113400..aadb7298dcefda4b6212e9b47c2ec36db4cea605 100644 (file)
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -734,6 +734,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
        struct mem_section *ms = __pfn_to_section(pfn);
        bool section_is_early = early_section(ms);
        struct page *memmap = NULL;
+       bool empty;
        unsigned long *subsection_map = ms->usage
                ? &ms->usage->subsection_map[0] : NULL;
 
@@ -764,7 +765,8 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
         * For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified
         */
        bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
-       if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) {
+       empty = bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION);
+       if (empty) {
                unsigned long section_nr = pfn_to_section_nr(pfn);
 
                /*
@@ -779,13 +781,15 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
                        ms->usage = NULL;
                }
                memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
-               ms->section_mem_map = (unsigned long)NULL;
        }
 
        if (section_is_early && memmap)
                free_map_bootmem(memmap);
        else
                depopulate_section_memmap(pfn, nr_pages, altmap);
+
+       if (empty)
+               ms->section_mem_map = (unsigned long)NULL;
 }
 
 static struct page * __meminit section_activate(int nid, unsigned long pfn,