[PATCH] md/bitmap: use set_bit etc for bitmap page attributes
In particular, this means that we use 4 bits per page instead of a whole
unsigned long.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 0f17325..2e257d5 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -700,27 +700,27 @@
}
enum bitmap_page_attr {
- BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
- BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
- BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
+ BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
+ BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
+ BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
};
static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
enum bitmap_page_attr attr)
{
- bitmap->filemap_attr[page->index] |= attr;
+ __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
}
static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
enum bitmap_page_attr attr)
{
- bitmap->filemap_attr[page->index] &= ~attr;
+ __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
}
static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
enum bitmap_page_attr attr)
{
- return bitmap->filemap_attr[page->index] & attr;
+ return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
}
/*
@@ -872,7 +872,12 @@
if (!bitmap->filemap)
goto out;
- bitmap->filemap_attr = kzalloc(sizeof(long) * num_pages, GFP_KERNEL);
+ /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
+ bitmap->filemap_attr = kzalloc(
+ (((num_pages*4/8)+sizeof(unsigned long)-1)
+ /sizeof(unsigned long))
+ *sizeof(unsigned long),
+ GFP_KERNEL);
if (!bitmap->filemap_attr)
goto out;