[PATCH] md/bitmap: cleaner separation of page attribute handlers in md/bitmap

md/bitmap has some attributes per-page.  Handling of these attributes in
largely abstracted in set_page_attr and clear_page_attr.  However
get_page_attr exposes the format used to store them.  So prior to changing
that format, introduce test_page_attr instead of get_page_attr, and make
appropriate usage changes.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 22 insertions, 19 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 814f412a410c..0f1732570770 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -717,9 +717,10 @@ static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
         bitmap->filemap_attr[page->index] &= ~attr;
 }
 
-static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
+static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
+                                           enum bitmap_page_attr attr)
 {
-        return bitmap->filemap_attr[page->index];
+        return bitmap->filemap_attr[page->index] & attr;
 }
 
 /*
@@ -745,7 +746,7 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 
 
         /* make sure the page stays cached until it gets written out */
-        if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
+        if (! test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY))
                 get_page(page);
 
         /* set the bit */
@@ -769,7 +770,8 @@ static void bitmap_writeback(struct bitmap *bitmap);
  * sync the dirty pages of the bitmap file to disk */
 int bitmap_unplug(struct bitmap *bitmap)
 {
-        unsigned long i, attr, flags;
+        unsigned long i, flags;
+        int dirty, need_write;
         struct page *page;
         int wait = 0;
         int err;
@@ -786,17 +788,18 @@ int bitmap_unplug(struct bitmap *bitmap)
                         return 0;
                 }
                 page = bitmap->filemap[i];
-                attr = get_page_attr(bitmap, page);
+                dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
+                need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
-                if ((attr & BITMAP_PAGE_DIRTY))
+                if (dirty)
                         wait = 1;
                 spin_unlock_irqrestore(&bitmap->lock, flags);
 
-                if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE)) {
+                if (dirty | need_write) {
                         err = write_page(bitmap, page, 0);
                         if (err == -EAGAIN) {
-                                if (attr & BITMAP_PAGE_DIRTY)
+                                if (dirty)
                                         err = write_page(bitmap, page, 1);
                                 else
                                         err = 0;
@@ -961,12 +964,11 @@ void bitmap_write_all(struct bitmap *bitmap)
         /* We don't actually write all bitmap blocks here,
          * just flag them as needing to be written
          */
+        int i;
 
-        unsigned long chunks = bitmap->chunks;
-        unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
-        unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
-        while (num_pages--)
-                bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
+        for (i=0; i < bitmap->file_pages; i++)
+                set_page_attr(bitmap, bitmap->filemap[i],
+                              BITMAP_PAGE_NEEDWRITE);
 }
 
 
@@ -997,7 +999,6 @@ int bitmap_daemon_work(struct bitmap *bitmap)
         struct page *page = NULL, *lastpage = NULL;
         int err = 0;
         int blocks;
-        int attr;
         void *paddr;
 
         if (bitmap == NULL)
@@ -1019,13 +1020,15 @@ int bitmap_daemon_work(struct bitmap *bitmap)
 
                 if (page != lastpage) {
                         /* skip this page unless it's marked as needing cleaning */
-                        if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
-                                if (attr & BITMAP_PAGE_NEEDWRITE) {
+                        if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
+                                int need_write = test_page_attr(bitmap, page,
+                                                                BITMAP_PAGE_NEEDWRITE);
+                                if (need_write) {
                                         get_page(page);
                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
                                 }
                                 spin_unlock_irqrestore(&bitmap->lock, flags);
-                                if (attr & BITMAP_PAGE_NEEDWRITE) {
+                                if (need_write) {
                                         switch (write_page(bitmap, page, 0)) {
                                         case -EAGAIN:
                                                 set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
@@ -1043,7 +1046,7 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                         /* grab the new page, sync and release the old */
                         get_page(page);
                         if (lastpage != NULL) {
-                                if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
+                                if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                                         spin_unlock_irqrestore(&bitmap->lock, flags);
                                         err = write_page(bitmap, lastpage, 0);
@@ -1097,7 +1100,7 @@ int bitmap_daemon_work(struct bitmap *bitmap)
         /* now sync the final page */
         if (lastpage != NULL) {
                 spin_lock_irqsave(&bitmap->lock, flags);
-                if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
+                if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                         spin_unlock_irqrestore(&bitmap->lock, flags);
                         err = write_page(bitmap, lastpage, 0);