zsmalloc: Stop using slab fields in struct page

The ->freelist and ->units members of struct page are for the use of
slab only.  I'm not particularly familiar with zsmalloc, so generate the
same code by using page->index to store 'page' (page->index and
page->freelist are at the same offset in struct page).  This should be
cleaned up properly at some point by somebody who is familiar with
zsmalloc.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index b897ce3..0d3b659 100644 (file)
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -17,10 +17,10 @@
  *
  * Usage of struct page fields:
  *     page->private: points to zspage
- *     page->freelist(index): links together all component pages of a zspage
+ *     page->index: links together all component pages of a zspage
  *             For the huge page, this is always 0, so we use this field
  *             to store handle.
- *     page->units: first object offset in a subpage of zspage
+ *     page->page_type: first object offset in a subpage of zspage
  *
  * Usage of struct page flags:
  *     PG_private: identifies the first component page
@@ -489,12 +489,12 @@ static inline struct page *get_first_page(struct zspage *zspage)
 
 static inline int get_first_obj_offset(struct page *page)
 {
-       return page->units;
+       return page->page_type;
 }
 
 static inline void set_first_obj_offset(struct page *page, int offset)
 {
-       page->units = offset;
+       page->page_type = offset;
 }
 
 static inline unsigned int get_freeobj(struct zspage *zspage)
@@ -827,7 +827,7 @@ static struct page *get_next_page(struct page *page)
        if (unlikely(PageHugeObject(page)))
                return NULL;
 
-       return page->freelist;
+       return (struct page *)page->index;
 }
 
 /**
@@ -901,7 +901,7 @@ static void reset_page(struct page *page)
        set_page_private(page, 0);
        page_mapcount_reset(page);
        ClearPageHugeObject(page);
-       page->freelist = NULL;
+       page->index = 0;
 }
 
 static int trylock_zspage(struct zspage *zspage)
@@ -1027,7 +1027,7 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage,
 
        /*
         * Allocate individual pages and link them together as:
-        * 1. all pages are linked together using page->freelist
+        * 1. all pages are linked together using page->index
         * 2. each sub-page point to zspage using page->private
         *
         * we set PG_private to identify the first page (i.e. no other sub-page
@@ -1036,7 +1036,7 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage,
        for (i = 0; i < nr_pages; i++) {
                page = pages[i];
                set_page_private(page, (unsigned long)zspage);
-               page->freelist = NULL;
+               page->index = 0;
                if (i == 0) {
                        zspage->first_page = page;
                        SetPagePrivate(page);
@@ -1044,7 +1044,7 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage,
                                        class->pages_per_zspage == 1))
                                SetPageHugeObject(page);
                } else {
-                       prev_page->freelist = page;
+                       prev_page->index = (unsigned long)page;
                }
                prev_page = page;
        }