powerpc/mm/radix: Free PUD table when freeing pagetable

remove_pagetable() isn't freeing PUD table. This causes memory
leak during memory unplug. Fix this.

Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()")
Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200709131925.922266-3-aneesh.kumar@linux.ibm.com

diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 85806a6..46ad2da 100644 (file)
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -707,6 +707,21 @@ static void free_pmd_table(pmd_t *pmd_start, pud_t *pud)
        pud_clear(pud);
 }
 
+static void free_pud_table(pud_t *pud_start, p4d_t *p4d)
+{
+       pud_t *pud;
+       int i;
+
+       for (i = 0; i < PTRS_PER_PUD; i++) {
+               pud = pud_start + i;
+               if (!pud_none(*pud))
+                       return;
+       }
+
+       pud_free(&init_mm, pud_start);
+       p4d_clear(p4d);
+}
+
 struct change_mapping_params {
        pte_t *pte;
        unsigned long start;
@@ -881,6 +896,7 @@ static void __meminit remove_pagetable(unsigned long start, unsigned long end)
 
                pud_base = (pud_t *)p4d_page_vaddr(*p4d);
                remove_pud_table(pud_base, addr, next);
+               free_pud_table(pud_base, p4d);
        }
 
        spin_unlock(&init_mm.page_table_lock);