[PATCH 09/12] mm, uprobes: convert __replace_page() to page_check_walk()

From: Kirill A. Shutemov
Date: Tue Jan 24 2017 - 11:31:10 EST


For consistency, it worth converting all page_check_address() to
page_check_walk(), so we could drop the former.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
kernel/events/uprobes.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 1e65c79e52a6..6dbaa93b22fa 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -153,14 +153,19 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
struct page *old_page, struct page *new_page)
{
struct mm_struct *mm = vma->vm_mm;
- spinlock_t *ptl;
- pte_t *ptep;
+ struct page_check_walk pcw = {
+ .page = old_page,
+ .vma = vma,
+ .address = addr,
+ };
int err;
/* For mmu_notifiers */
const unsigned long mmun_start = addr;
const unsigned long mmun_end = addr + PAGE_SIZE;
struct mem_cgroup *memcg;

+ VM_BUG_ON_PAGE(PageTransHuge(old_page), old_page);
+
err = mem_cgroup_try_charge(new_page, vma->vm_mm, GFP_KERNEL, &memcg,
false);
if (err)
@@ -171,11 +176,11 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,

mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
err = -EAGAIN;
- ptep = page_check_address(old_page, mm, addr, &ptl, 0);
- if (!ptep) {
+ if (!page_check_walk(&pcw)) {
mem_cgroup_cancel_charge(new_page, memcg, false);
goto unlock;
}
+ VM_BUG_ON_PAGE(addr != pcw.address, old_page);

get_page(new_page);
page_add_new_anon_rmap(new_page, vma, addr, false);
@@ -187,14 +192,15 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
inc_mm_counter(mm, MM_ANONPAGES);
}

- flush_cache_page(vma, addr, pte_pfn(*ptep));
- ptep_clear_flush_notify(vma, addr, ptep);
- set_pte_at_notify(mm, addr, ptep, mk_pte(new_page, vma->vm_page_prot));
+ flush_cache_page(vma, addr, pte_pfn(*pcw.pte));
+ ptep_clear_flush_notify(vma, addr, pcw.pte);
+ set_pte_at_notify(mm, addr, pcw.pte,
+ mk_pte(new_page, vma->vm_page_prot));

page_remove_rmap(old_page, false);
if (!page_mapped(old_page))
try_to_free_swap(old_page);
- pte_unmap_unlock(ptep, ptl);
+ page_check_walk_done(&pcw);

if (vma->vm_flags & VM_LOCKED)
munlock_vma_page(old_page);
--
2.11.0