Commit e16b68b6 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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[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: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ec7a3197

drivers/md/bitmap.c

+12 −7
Original line number Diff line number Diff line
@@ -700,27 +700,27 @@ static void bitmap_file_kick(struct bitmap *bitmap) 
}



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 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start) 
	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;