erofs: get rid of ->lru usage

Currently, ->lru is a way to arrange non-LRU pages and has some
in-kernel users. In order to minimize noticable issues of page
reclaim and cache thrashing under high memory presure, limited
temporary pages were all chained with ->lru and can be reused
during the request. However, it seems that ->lru could be removed
when folio is landing.

Let's use page->private to chain temporary pages for now instead
and transform EROFS formally after the topic of the folio / file
page design is finalized.

Link: https://lore.kernel.org/r/20211022090120.14675-1-hsiangkao@linux.alibaba.com
Cc: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index a6a53d22dfd6..3265688af7f9 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -499,7 +499,14 @@ void erofs_pcpubuf_init(void);
 void erofs_pcpubuf_exit(void);
 
 /* utils.c / zdata.c */
-struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp);
+struct page *erofs_allocpage(struct page **pagepool, gfp_t gfp);
+static inline void erofs_pagepool_add(struct page **pagepool,
+		struct page *page)
+{
+	set_page_private(page, (unsigned long)*pagepool);
+	*pagepool = page;
+}
+void erofs_release_pages(struct page **pagepool);
 
 #ifdef CONFIG_EROFS_FS_ZIP
 int erofs_workgroup_put(struct erofs_workgroup *grp);