[PATCH v1 3/9] s390/vmemmap: implement vmemmap_free()

David Hildenbrand
2020-07-03T13:40:01Z

Reuse the shiny new remove_pagetable(), tweaking it to handle freeing of
vmemmap pages, similar to the x86-64 variant (passing "bool direct" to
distinguish).

Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/s390/mm/vmem.c | 46 ++++++++++++++++++++++++++++++++-------------
1 file changed, 33 insertions(+), 13 deletions(-)

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 6fe156c3f035c..16e109c292bf5 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -29,6 +29,15 @@ static void __ref *vmem_alloc_pages(unsigned int order)
return (void *) memblock_phys_alloc(size, size);
}

+static void vmem_free_pages(unsigned long addr, int order)
+{
+ /* We don't expect boot memory to be removed ever. */
+ if (!slab_is_available() ||
+ WARN_ON_ONCE(PageReserved(phys_to_page(addr))))
+ return;
+ free_pages(addr, order);
+}
+
void *vmem_crst_alloc(unsigned long val)
{
unsigned long *table;
@@ -139,7 +148,7 @@ static int vmem_add_range(unsigned long start, unsigned long size)
}

static void remove_pte_table(pmd_t *pmd, unsigned long addr,
- unsigned long end)
+ unsigned long end, bool direct)
{
unsigned long pages = 0;
pte_t *pte;
@@ -149,15 +158,18 @@ static void remove_pte_table(pmd_t *pmd, unsigned long addr,
if (pte_none(*pte))
continue;

+ if (!direct)
+ vmem_free_pages(pfn_to_phys(pte_pfn(*pte)), 0);
pte_clear(&init_mm, addr, pte);
pages++;
}

- update_page_count(PG_DIRECT_MAP_4K, -pages);
+ if (direct)
+ update_page_count(PG_DIRECT_MAP_4K, -pages);
}

static void remove_pmd_table(pud_t *pud, unsigned long addr,
- unsigned long end)
+ unsigned long end, bool direct)
{
unsigned long next, pages = 0;
pmd_t *pmd;
@@ -172,20 +184,24 @@ static void remove_pmd_table(pud_t *pud, unsigned long addr,
if (pmd_large(*pmd)) {
if (IS_ALIGNED(addr, PMD_SIZE) &&
IS_ALIGNED(next, PMD_SIZE)) {
+ if (!direct)
+ vmem_free_pages(pmd_deref(*pmd),
+ get_order(PMD_SIZE));
pmd_clear(pmd);
pages++;
}
continue;
}

- remove_pte_table(pmd, addr, next);
+ remove_pte_table(pmd, addr, next, direct);
}

- update_page_count(PG_DIRECT_MAP_1M, -pages);
+ if (direct)
+ update_page_count(PG_DIRECT_MAP_1M, -pages);
}

static void remove_pud_table(p4d_t *p4d, unsigned long addr,
- unsigned long end)
+ unsigned long end, bool direct)
{
unsigned long next, pages = 0;
pud_t *pud;
@@ -200,20 +216,22 @@ static void remove_pud_table(p4d_t *p4d, unsigned long addr,
if (pud_large(*pud)) {
if (IS_ALIGNED(addr, PUD_SIZE) &&
IS_ALIGNED(next, PUD_SIZE)) {
+ WARN_ON_ONCE(!direct);
pud_clear(pud);
pages++;
}
continue;
}

- remove_pmd_table(pud, addr, next);
+ remove_pmd_table(pud, addr, next, direct);
}

- update_page_count(PG_DIRECT_MAP_2G, -pages);
+ if (direct)
+ update_page_count(PG_DIRECT_MAP_2G, -pages);
}

static void remove_p4d_table(pgd_t *pgd, unsigned long addr,
- unsigned long end)
+ unsigned long end, bool direct)
{
unsigned long next;
p4d_t *p4d;
@@ -225,11 +243,12 @@ static void remove_p4d_table(pgd_t *pgd, unsigned long addr,
if (p4d_none(*p4d))
continue;

- remove_pud_table(p4d, addr, next);
+ remove_pud_table(p4d, addr, next, direct);
}
}

-static void remove_pagetable(unsigned long start, unsigned long end)
+static void remove_pagetable(unsigned long start, unsigned long end,
+ bool direct)
{
unsigned long addr, next;
pgd_t *pgd;
@@ -244,7 +263,7 @@ static void remove_pagetable(unsigned long start, unsigned long end)
if (pgd_none(*pgd))
continue;

- remove_p4d_table(pgd, addr, next);
+ remove_p4d_table(pgd, addr, next, direct);
}

flush_tlb_kernel_range(start, end);
@@ -256,7 +275,7 @@ static void remove_pagetable(unsigned long start, unsigned long end)
*/
static void vmem_remove_range(unsigned long start, unsigned long size)
{
- remove_pagetable(start, start + size);
+ remove_pagetable(start, start + size, true);
}

/*
@@ -351,6 +370,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
void vmemmap_free(unsigned long start, unsigned long end,
struct vmem_altmap *altmap)
{
+ remove_pagetable(start, end, false);
}

void vmem_remove_mapping(unsigned long start, unsigned long size)
--
2.26.2