Re: [PATCH 1/2] mm: remove page_rmapping()

From: zhangpeng (AS)
Date: Fri Jun 30 2023 - 23:27:07 EST


On 2023/7/1 0:03, Sidhartha Kumar wrote:

On 6/30/23 5:13 AM, Peng Zhang wrote:
From: ZhangPeng <zhangpeng362@xxxxxxxxxx>

After converting the last user to folio_raw_mapping(), we can safely
remove the function.

Signed-off-by: ZhangPeng <zhangpeng362@xxxxxxxxxx>
---
  include/linux/mm.h | 1 -
  mm/memory.c        | 2 +-
  mm/util.c          | 6 ------
  3 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9ecb8b9c07f6..8c7eba7370b2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2129,7 +2129,6 @@ static inline void *folio_address(const struct folio *folio)
      return page_address(&folio->page);
  }
  -extern void *page_rmapping(struct page *page);
  extern pgoff_t __page_file_index(struct page *page);
    /*
diff --git a/mm/memory.c b/mm/memory.c
index 21fab2727209..6921df44a99f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2979,7 +2979,7 @@ static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf)
       * pinned by vma->vm_file's reference.  We rely on unlock_page()'s
       * release semantics to prevent the compiler from undoing this copying.
       */


    struct page *page = vmf->page;

    ...

    dirtied = set_page_dirty(page);
    VM_BUG_ON_PAGE(PageAnon(page), page);

Can this earlier part of the function be converted to folios so a folio can be passed directly in folio_raw_mapping()?

Thanks for your feedback.

I convert the last user to use a folio in patch 2. I'll reverse the order of the two patches.

Best Regards,
Peng

-    mapping = page_rmapping(page);
+    mapping = folio_raw_mapping(page_folio(page));
      unlock_page(page);
        if (!page_mkwrite)
diff --git a/mm/util.c b/mm/util.c
index dd12b9531ac4..5e9305189c3f 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -734,12 +734,6 @@ void *vcalloc(size_t n, size_t size)
  }
  EXPORT_SYMBOL(vcalloc);
  -/* Neutral page->mapping pointer to address_space or anon_vma or other */
-void *page_rmapping(struct page *page)
-{
-    return folio_raw_mapping(page_folio(page));
-}
-
  struct anon_vma *folio_anon_vma(struct folio *folio)
  {
      unsigned long mapping = (unsigned long)folio->mapping;