[PATCH v14 123/138] mm/filemap: Use a folio in filemap_map_pages

Matthew Wilcox (Oracle)
2021-07-15T05:17:53Z

Saves 61 bytes due to fewer calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
mm/filemap.c | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 545323a77c1c..1c0c2663c57d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3105,7 +3105,7 @@ static bool filemap_map_pmd(struct vm_fault *vmf, struct page *page)
return false;
}

-static struct page *next_uptodate_page(struct folio *folio,
+static struct folio *next_uptodate_page(struct folio *folio,
struct address_space *mapping,
struct xa_state *xas, pgoff_t end_pgoff)
{
@@ -3136,7 +3136,7 @@ static struct page *next_uptodate_page(struct folio *folio,
max_idx = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE);
if (xas->xa_index >= max_idx)
goto unlock;
- return &folio->page;
+ return folio;
unlock:
folio_unlock(folio);
skip:
@@ -3146,7 +3146,7 @@ static struct page *next_uptodate_page(struct folio *folio,
return NULL;
}

-static inline struct page *first_map_page(struct address_space *mapping,
+static inline struct folio *first_map_page(struct address_space *mapping,
struct xa_state *xas,
pgoff_t end_pgoff)
{
@@ -3154,7 +3154,7 @@ static inline struct page *first_map_page(struct address_space *mapping,
mapping, xas, end_pgoff);
}

-static inline struct page *next_map_page(struct address_space *mapping,
+static inline struct folio *next_map_page(struct address_space *mapping,
struct xa_state *xas,
pgoff_t end_pgoff)
{
@@ -3171,16 +3171,17 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
pgoff_t last_pgoff = start_pgoff;
unsigned long addr;
XA_STATE(xas, &mapping->i_pages, start_pgoff);
- struct page *head, *page;
+ struct folio *folio;
+ struct page *page;
unsigned int mmap_miss = READ_ONCE(file->f_ra.mmap_miss);
vm_fault_t ret = 0;

rcu_read_lock();
- head = first_map_page(mapping, &xas, end_pgoff);
- if (!head)
+ folio = first_map_page(mapping, &xas, end_pgoff);
+ if (!folio)
goto out;

- if (filemap_map_pmd(vmf, head)) {
+ if (filemap_map_pmd(vmf, &folio->page)) {
ret = VM_FAULT_NOPAGE;
goto out;
}
@@ -3188,7 +3189,7 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
addr = vma->vm_start + ((start_pgoff - vma->vm_pgoff) << PAGE_SHIFT);
vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, addr, &vmf->ptl);
do {
- page = find_subpage(head, xas.xa_index);
+ page = folio_file_page(folio, xas.xa_index);
if (PageHWPoison(page))
goto unlock;

@@ -3209,12 +3210,12 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
do_set_pte(vmf, page, addr);
/* no need to invalidate: a not-present page won't be cached */
update_mmu_cache(vma, addr, vmf->pte);
- unlock_page(head);
+ folio_unlock(folio);
continue;
unlock:
- unlock_page(head);
- put_page(head);
- } while ((head = next_map_page(mapping, &xas, end_pgoff)) != NULL);
+ folio_unlock(folio);
+ folio_put(folio);
+ } while ((folio = next_map_page(mapping, &xas, end_pgoff)) != NULL);
pte_unmap_unlock(vmf->pte, vmf->ptl);
out:
rcu_read_unlock();
--
2.30.2