[PATCH 24/25] mm: Add read_cache_folio and read_mapping_folio
From: Matthew Wilcox (Oracle)
Date: Wed Dec 16 2020 - 13:25:54 EST
Reimplement read_cache_page() as a wrapper around read_cache_folio().
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/linux/pagemap.h | 17 ++++++++-
mm/filemap.c | 81 +++++++++++++++++++----------------------
2 files changed, 53 insertions(+), 45 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 22f9774d8a83..ae20b6fa46f0 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -518,19 +518,32 @@ static inline struct page *grab_cache_page(struct address_space *mapping,
return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
}
-extern struct page * read_cache_page(struct address_space *mapping,
- pgoff_t index, filler_t *filler, void *data);
+struct folio *read_cache_folio(struct address_space *mapping, pgoff_t index,
+ filler_t *filler, void *data);
extern struct page * read_cache_page_gfp(struct address_space *mapping,
pgoff_t index, gfp_t gfp_mask);
extern int read_cache_pages(struct address_space *mapping,
struct list_head *pages, filler_t *filler, void *data);
+static inline struct page *read_cache_page(struct address_space *mapping,
+ pgoff_t index, filler_t *filler, void *data)
+{
+ struct folio *folio = read_cache_folio(mapping, index, filler, data);
+ return folio_page(folio, index);
+}
+
static inline struct page *read_mapping_page(struct address_space *mapping,
pgoff_t index, void *data)
{
return read_cache_page(mapping, index, NULL, data);
}
+static inline struct folio *read_mapping_folio(struct address_space *mapping,
+ pgoff_t index, void *data)
+{
+ return read_cache_folio(mapping, index, NULL, data);
+}
+
/*
* Get index of the page with in radix-tree
* (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE)
diff --git a/mm/filemap.c b/mm/filemap.c
index a5925450ee13..0131208e45f7 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3174,32 +3174,20 @@ EXPORT_SYMBOL(filemap_page_mkwrite);
EXPORT_SYMBOL(generic_file_mmap);
EXPORT_SYMBOL(generic_file_readonly_mmap);
-static struct page *wait_on_page_read(struct page *page)
-{
- if (!IS_ERR(page)) {
- wait_on_page_locked(page);
- if (!PageUptodate(page)) {
- put_page(page);
- page = ERR_PTR(-EIO);
- }
- }
- return page;
-}
-
-static struct page *do_read_cache_page(struct address_space *mapping,
+static struct folio *do_read_cache_folio(struct address_space *mapping,
pgoff_t index, filler_t filler, void *data, gfp_t gfp)
{
- struct page *page;
+ struct folio *folio;
int err;
repeat:
- page = find_get_page(mapping, index);
- if (!page) {
- page = &__page_cache_alloc(gfp, 0)->page;
- if (!page)
+ folio = find_get_folio(mapping, index);
+ if (!folio) {
+ folio = __page_cache_alloc(gfp, 0);
+ if (!folio)
return ERR_PTR(-ENOMEM);
- err = add_to_page_cache_lru(page, mapping, index, gfp);
+ err = folio_add_to_page_cache(folio, mapping, index, gfp);
if (unlikely(err)) {
- put_page(page);
+ put_folio(folio);
if (err == -EEXIST)
goto repeat;
/* Presumably ENOMEM for xarray node */
@@ -3208,21 +3196,24 @@ static struct page *do_read_cache_page(struct address_space *mapping,
filler:
if (filler)
- err = filler(data, page_folio(page));
+ err = filler(data, folio);
else
- err = mapping->a_ops->readpage(data, page_folio(page));
+ err = mapping->a_ops->readpage(data, folio);
if (err < 0) {
- put_page(page);
+ put_folio(folio);
return ERR_PTR(err);
}
- page = wait_on_page_read(page);
- if (IS_ERR(page))
- return page;
+ wait_on_folio_locked(folio);
+ if (!FolioUptodate(folio)) {
+ put_folio(folio);
+ return ERR_PTR(-EIO);
+ }
+
goto out;
}
- if (PageUptodate(page))
+ if (FolioUptodate(folio))
goto out;
/*
@@ -3256,23 +3247,23 @@ static struct page *do_read_cache_page(struct address_space *mapping,
* avoid spurious serialisations and wakeups when multiple processes
* wait on the same page for IO to complete.
*/
- wait_on_page_locked(page);
- if (PageUptodate(page))
+ wait_on_folio_locked(folio);
+ if (FolioUptodate(folio))
goto out;
/* Distinguish between all the cases under the safety of the lock */
- lock_page(page);
+ lock_folio(folio);
/* Case c or d, restart the operation */
- if (!page->mapping) {
- unlock_page(page);
- put_page(page);
+ if (!folio->page.mapping) {
+ unlock_folio(folio);
+ put_folio(folio);
goto repeat;
}
/* Someone else locked and filled the page in a very small window */
- if (PageUptodate(page)) {
- unlock_page(page);
+ if (FolioUptodate(folio)) {
+ unlock_folio(folio);
goto out;
}
@@ -3282,16 +3273,16 @@ static struct page *do_read_cache_page(struct address_space *mapping,
* Clear page error before actual read, PG_error will be
* set again if read page fails.
*/
- ClearPageError(page);
+ ClearFolioError(folio);
goto filler;
out:
- mark_page_accessed(page);
- return page;
+ mark_folio_accessed(folio);
+ return folio;
}
/**
- * read_cache_page - read into page cache, fill it if needed
+ * read_cache_folio - read into page cache, fill it if needed
* @mapping: the page's address_space
* @index: the page index
* @filler: function to perform the read
@@ -3304,13 +3295,13 @@ static struct page *do_read_cache_page(struct address_space *mapping,
*
* Return: up to date page on success, ERR_PTR() on failure.
*/
-struct page *read_cache_page(struct address_space *mapping, pgoff_t index,
+struct folio *read_cache_folio(struct address_space *mapping, pgoff_t index,
filler_t filler, void *data)
{
- return do_read_cache_page(mapping, index, filler, data,
+ return do_read_cache_folio(mapping, index, filler, data,
mapping_gfp_mask(mapping));
}
-EXPORT_SYMBOL(read_cache_page);
+EXPORT_SYMBOL(read_cache_folio);
/**
* read_cache_page_gfp - read into page cache, using specified page allocation flags.
@@ -3329,7 +3320,11 @@ struct page *read_cache_page_gfp(struct address_space *mapping,
pgoff_t index,
gfp_t gfp)
{
- return do_read_cache_page(mapping, index, NULL, NULL, gfp);
+ struct folio *folio = do_read_cache_folio(mapping, index, NULL, NULL,
+ gfp);
+ if (IS_ERR(folio))
+ return &folio->page;
+ return folio_page(folio, index);
}
EXPORT_SYMBOL(read_cache_page_gfp);
--
2.29.2