powerpc: implement vmemmap_free()

vmemmap_free() does the opposite of vmemap_populate().
This patch also puts vmemmap_free() and vmemmap_list_free() into
 CONFIG_MEMMORY_HOTPLUG.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 69203c8..4963790 100644 (file)
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -298,6 +298,37 @@ static __meminit void vmemmap_list_populate(unsigned long phys,
        vmemmap_list = vmem_back;
 }
 
+int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
+{
+       unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
+
+       /* Align to the page size of the linear mapping. */
+       start = _ALIGN_DOWN(start, page_size);
+
+       pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
+
+       for (; start < end; start += page_size) {
+               void *p;
+
+               if (vmemmap_populated(start, page_size))
+                       continue;
+
+               p = vmemmap_alloc_block(page_size, node);
+               if (!p)
+                       return -ENOMEM;
+
+               vmemmap_list_populate(__pa(p), start, node);
+
+               pr_debug("      * %016lx..%016lx allocated at %p\n",
+                        start, start + page_size, p);
+
+               vmemmap_create_mapping(start, page_size, __pa(p));
+       }
+
+       return 0;
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
 static unsigned long vmemmap_list_free(unsigned long start)
 {
        struct vmemmap_backing *vmem_back, *vmem_back_prev;
@@ -330,40 +361,52 @@ static unsigned long vmemmap_list_free(unsigned long start)
        return vmem_back->phys;
 }
 
-int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
+void __ref vmemmap_free(unsigned long start, unsigned long end)
 {
        unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
 
-       /* Align to the page size of the linear mapping. */
        start = _ALIGN_DOWN(start, page_size);
 
-       pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
+       pr_debug("vmemmap_free %lx...%lx\n", start, end);
 
        for (; start < end; start += page_size) {
-               void *p;
+               unsigned long addr;
 
+               /*
+                * the section has already be marked as invalid, so
+                * vmemmap_populated() true means some other sections still
+                * in this page, so skip it.
+                */
                if (vmemmap_populated(start, page_size))
                        continue;
 
-               p = vmemmap_alloc_block(page_size, node);
-               if (!p)
-                       return -ENOMEM;
-
-               vmemmap_list_populate(__pa(p), start, node);
-
-               pr_debug("      * %016lx..%016lx allocated at %p\n",
-                        start, start + page_size, p);
-
-               vmemmap_create_mapping(start, page_size, __pa(p));
+               addr = vmemmap_list_free(start);
+               if (addr) {
+                       struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
+
+                       if (PageReserved(page)) {
+                               /* allocated from bootmem */
+                               if (page_size < PAGE_SIZE) {
+                                       /*
+                                        * this shouldn't happen, but if it is
+                                        * the case, leave the memory there
+                                        */
+                                       WARN_ON_ONCE(1);
+                               } else {
+                                       unsigned int nr_pages =
+                                               1 << get_order(page_size);
+                                       while (nr_pages--)
+                                               free_reserved_page(page++);
+                               }
+                       } else
+                               free_pages((unsigned long)(__va(addr)),
+                                                       get_order(page_size));
+
+                       vmemmap_remove_mapping(start, page_size);
+               }
        }
-
-       return 0;
-}
-
-void vmemmap_free(unsigned long start, unsigned long end)
-{
 }
-
+#endif
 void register_page_bootmem_memmap(unsigned long section_nr,
                                  struct page *start_page, unsigned long size)
 {