Re: [PATCH v2 2/4] powerpc/mm/radix: Free PUD table when freeing pagetable

[Aneesh Kumar K.V]

On 7/8/20 7:42 AM, Michael Ellerman wrote:

"Aneesh Kumar K.V" <aneesh.ku...@linux.ibm.com> writes:

From: Bharata B Rao <bhar...@linux.ibm.com>

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()")

Fixes: ??

cheers

Signed-off-by: Bharata B Rao <bhar...@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
  arch/powerpc/mm/book3s64/radix_pgtable.c | 16 ++++++++++++++++
  1 file changed, 16 insertions(+)

diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c 
b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 80be96d3018f..af57604f295f 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -708,6 +708,21 @@ 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;
@@ -882,6 +897,7 @@ 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);

--
2.26.2