[RFC PATCH 63/79] mm/page: convert page's index lookup to be against specific mapping

From: jglisse
Date: Wed Apr 04 2018 - 15:24:26 EST


From: JÃrÃme Glisse <jglisse@xxxxxxxxxx>

This patch switch mm to lookup the page index or offset value to be
against specific mapping. The page index value only have a meaning
against a mapping.

Using coccinelle:
---------------------------------------------------------------------
@@
struct page *P;
expression E;
@@
-P->index = E
+page_set_index(P, E)

@@
struct page *P;
@@
-P->index
+page_index(P)

@@
struct page *P;
@@
-page_index(P) << PAGE_SHIFT
+page_offset(P)

@@
expression E;
@@
-page_index(E)
+_page_index(E, mapping)

@@
expression E1, E2;
@@
-page_set_index(E1, E2)
+_page_set_index(E1, mapping, E2)

@@
expression E;
@@
-page_to_index(E)
+_page_to_index(E, mapping)

@@
expression E;
@@
-page_to_pgoff(E)
+_page_to_pgoff(E, mapping)

@@
expression E;
@@
-page_offset(E)
+_page_offset(E, mapping)

@@
expression E;
@@
-page_file_offset(E)
+_page_file_offset(E, mapping)
---------------------------------------------------------------------

Signed-off-by: JÃrÃme Glisse <jglisse@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
mm/filemap.c | 26 ++++++++++++++------------
mm/page-writeback.c | 16 +++++++++-------
mm/shmem.c | 11 +++++++----
mm/truncate.c | 11 ++++++-----
4 files changed, 36 insertions(+), 28 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 012a53964215..a41c7cfb6351 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -118,7 +118,8 @@ static int page_cache_tree_insert(struct address_space *mapping,
void **slot;
int error;

- error = __radix_tree_create(&mapping->page_tree, page->index, 0,
+ error = __radix_tree_create(&mapping->page_tree,
+ _page_index(page, mapping), 0,
&node, &slot);
if (error)
return error;
@@ -155,7 +156,8 @@ static void page_cache_tree_delete(struct address_space *mapping,
struct radix_tree_node *node;
void **slot;

- __radix_tree_lookup(&mapping->page_tree, page->index + i,
+ __radix_tree_lookup(&mapping->page_tree,
+ _page_index(page, mapping) + i,
&node, &slot);

VM_BUG_ON_PAGE(!node && nr != 1, page);
@@ -791,12 +793,12 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
void (*freepage)(struct page *);
unsigned long flags;

- pgoff_t offset = old->index;
+ pgoff_t offset = _page_index(old, mapping);
freepage = mapping->a_ops->freepage;

get_page(new);
new->mapping = mapping;
- new->index = offset;
+ _page_set_index(new, mapping, offset);

spin_lock_irqsave(&mapping->tree_lock, flags);
__delete_from_page_cache(old, NULL);
@@ -850,7 +852,7 @@ static int __add_to_page_cache_locked(struct page *page,

get_page(page);
page->mapping = mapping;
- page->index = offset;
+ _page_set_index(page, mapping, offset);

spin_lock_irq(&mapping->tree_lock);
error = page_cache_tree_insert(mapping, page, shadowp);
@@ -1500,7 +1502,7 @@ struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset)
put_page(page);
goto repeat;
}
- VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page);
+ VM_BUG_ON_PAGE(_page_to_pgoff(page, mapping) != offset, page);
}
return page;
}
@@ -1559,7 +1561,7 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
put_page(page);
goto repeat;
}
- VM_BUG_ON_PAGE(page->index != offset, page);
+ VM_BUG_ON_PAGE(_page_index(page, mapping) != offset, page);
}

if (page && (fgp_flags & FGP_ACCESSED))
@@ -1751,7 +1753,7 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,

pages[ret] = page;
if (++ret == nr_pages) {
- *start = pages[ret - 1]->index + 1;
+ *start = _page_index(pages[ret - 1], mapping) + 1;
goto out;
}
}
@@ -1837,7 +1839,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
* otherwise we can get both false positives and false
* negatives, which is just confusing to the caller.
*/
- if (page->mapping == NULL || page_to_pgoff(page) != iter.index) {
+ if (page->mapping == NULL || _page_to_pgoff(page, mapping) != iter.index) {
put_page(page);
break;
}
@@ -1923,7 +1925,7 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,

pages[ret] = page;
if (++ret == nr_pages) {
- *index = pages[ret - 1]->index + 1;
+ *index = _page_index(pages[ret - 1], mapping) + 1;
goto out;
}
}
@@ -2540,7 +2542,7 @@ int filemap_fault(struct vm_fault *vmf)
put_page(page);
goto retry_find;
}
- VM_BUG_ON_PAGE(page->index != offset, page);
+ VM_BUG_ON_PAGE(_page_index(page, mapping) != offset, page);

/*
* We have a locked page in the page cache, now we need to check
@@ -2667,7 +2669,7 @@ void filemap_map_pages(struct vm_fault *vmf,
goto unlock;

max_idx = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE);
- if (page->index >= max_idx)
+ if (_page_index(page, mapping) >= max_idx)
goto unlock;

if (file->f_ra.mmap_miss > 0)
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 3c14d44639c8..ed9424f84715 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2201,7 +2201,7 @@ int write_cache_pages(struct address_space *mapping,
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];

- done_index = page->index;
+ done_index = _page_index(page, mapping);

lock_page(page);

@@ -2251,7 +2251,8 @@ int write_cache_pages(struct address_space *mapping,
* not be suitable for data integrity
* writeout).
*/
- done_index = page->index + 1;
+ done_index = _page_index(page,
+ mapping) + 1;
done = 1;
break;
}
@@ -2470,7 +2471,8 @@ int __set_page_dirty_nobuffers(struct page *page)
BUG_ON(page_mapping(page) != mapping);
WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
account_page_dirtied(page, mapping);
- radix_tree_tag_set(&mapping->page_tree, page_index(page),
+ radix_tree_tag_set(&mapping->page_tree,
+ _page_index(page, mapping),
PAGECACHE_TAG_DIRTY);
spin_unlock_irqrestore(&mapping->tree_lock, flags);
unlock_page_memcg(page);
@@ -2732,7 +2734,7 @@ int test_clear_page_writeback(struct page *page)
ret = TestClearPageWriteback(page);
if (ret) {
radix_tree_tag_clear(&mapping->page_tree,
- page_index(page),
+ _page_index(page, mapping),
PAGECACHE_TAG_WRITEBACK);
if (bdi_cap_account_writeback(bdi)) {
struct bdi_writeback *wb = inode_to_wb(inode);
@@ -2785,7 +2787,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
PAGECACHE_TAG_WRITEBACK);

radix_tree_tag_set(&mapping->page_tree,
- page_index(page),
+ _page_index(page, mapping),
PAGECACHE_TAG_WRITEBACK);
if (bdi_cap_account_writeback(bdi))
inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK);
@@ -2800,11 +2802,11 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
}
if (!PageDirty(page))
radix_tree_tag_clear(&mapping->page_tree,
- page_index(page),
+ _page_index(page, mapping),
PAGECACHE_TAG_DIRTY);
if (!keep_write)
radix_tree_tag_clear(&mapping->page_tree,
- page_index(page),
+ _page_index(page, mapping),
PAGECACHE_TAG_TOWRITE);
spin_unlock_irqrestore(&mapping->tree_lock, flags);
} else {
diff --git a/mm/shmem.c b/mm/shmem.c
index 7fee65df10b4..7f3168d547c8 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -588,7 +588,7 @@ static int shmem_add_to_page_cache(struct page *page,

page_ref_add(page, nr);
page->mapping = mapping;
- page->index = index;
+ _page_set_index(page, mapping, index);

spin_lock_irq(&mapping->tree_lock);
if (PageTransHuge(page)) {
@@ -644,7 +644,9 @@ static void shmem_delete_from_page_cache(struct page *page, void *radswap)
VM_BUG_ON_PAGE(PageCompound(page), page);

spin_lock_irq(&mapping->tree_lock);
- error = shmem_radix_tree_replace(mapping, page->index, page, radswap);
+ error = shmem_radix_tree_replace(mapping, _page_index(page, mapping),
+ page,
+ radswap);
page->mapping = NULL;
mapping->nrpages--;
__dec_node_page_state(page, NR_FILE_PAGES);
@@ -822,7 +824,8 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
continue;
}

- VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page);
+ VM_BUG_ON_PAGE(_page_to_pgoff(page, mapping) != index,
+ page);

if (!trylock_page(page))
continue;
@@ -1267,7 +1270,7 @@ static int shmem_writepage(struct address_space *_mapping, struct page *page,
VM_BUG_ON_PAGE(PageCompound(page), page);
BUG_ON(!PageLocked(page));
mapping = page->mapping;
- index = page->index;
+ index = _page_index(page, mapping);
inode = mapping->host;
info = SHMEM_I(inode);
if (info->flags & VM_LOCKED)
diff --git a/mm/truncate.c b/mm/truncate.c
index a9415c96c966..57d4d0948f40 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -181,7 +181,8 @@ truncate_cleanup_page(struct address_space *mapping, struct page *page)
{
if (page_mapped(page)) {
pgoff_t nr = PageTransHuge(page) ? HPAGE_PMD_NR : 1;
- unmap_mapping_pages(mapping, page->index, nr, false);
+ unmap_mapping_pages(mapping, _page_index(page, mapping), nr,
+ false);
}

if (page_has_private(page))
@@ -353,7 +354,7 @@ void truncate_inode_pages_range(struct address_space *mapping,

if (!trylock_page(page))
continue;
- WARN_ON(page_to_index(page) != index);
+ WARN_ON(_page_to_index(page, mapping) != index);
if (PageWriteback(page)) {
unlock_page(page);
continue;
@@ -447,7 +448,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
continue;

lock_page(page);
- WARN_ON(page_to_index(page) != index);
+ WARN_ON(_page_to_index(page, mapping) != index);
wait_on_page_writeback(page);
truncate_inode_page(mapping, page);
unlock_page(page);
@@ -571,7 +572,7 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
if (!trylock_page(page))
continue;

- WARN_ON(page_to_index(page) != index);
+ WARN_ON(_page_to_index(page, mapping) != index);

/* Middle of THP: skip */
if (PageTransTail(page)) {
@@ -701,7 +702,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
}

lock_page(page);
- WARN_ON(page_to_index(page) != index);
+ WARN_ON(_page_to_index(page, mapping) != index);
if (page_is_truncated(page, mapping)) {
unlock_page(page);
continue;
--
2.14.3