ext4: move setup of the mpd structure to write_cache_pages_da()

Move the initialization of all of the fields of the mpd structure to
write_cache_pages_da().  This simplifies the code considerably.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c2e6af33823414341c8e2f13e807ce648f72ebe3..dcc2287433b6fe81c31b9592fca4b7013ad6ca5a 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2714,7 +2714,8 @@ static int ext4_da_writepages_trans_blocks(struct inode *inode)
 /*
  * write_cache_pages_da - walk the list of dirty pages of the given
  * address space and accumulate pages that need writing, and call
- * mpage_da_map_and_submit to map the pages and then write them.
+ * mpage_da_map_and_submit to map a single contiguous memory region
+ * and then write them.
  */
 static int write_cache_pages_da(struct address_space *mapping,
                                struct writeback_control *wbc,
@@ -2722,7 +2723,7 @@ static int write_cache_pages_da(struct address_space *mapping,
                                pgoff_t *done_index)
 {
        struct buffer_head      *bh, *head;
-       struct inode            *inode = mpd->inode;
+       struct inode            *inode = mapping->host;
        struct pagevec          pvec;
        unsigned int            nr_pages;
        sector_t                logical;
@@ -2730,6 +2731,9 @@ static int write_cache_pages_da(struct address_space *mapping,
        long                    nr_to_write = wbc->nr_to_write;
        int                     i, tag, ret = 0;
 
+       memset(mpd, 0, sizeof(struct mpage_da_data));
+       mpd->wbc = wbc;
+       mpd->inode = inode;
        pagevec_init(&pvec, 0);
        index = wbc->range_start >> PAGE_CACHE_SHIFT;
        end = wbc->range_end >> PAGE_CACHE_SHIFT;
@@ -2794,16 +2798,8 @@ static int write_cache_pages_da(struct address_space *mapping,
 
                        BUG_ON(PageWriteback(page));
 
-                       if (mpd->next_page != page->index) {
-                               /*
-                                * Start next extent of pages and blocks
-                                */
+                       if (mpd->next_page != page->index)
                                mpd->first_page = page->index;
-                               mpd->b_size = 0;
-                               mpd->b_state = 0;
-                               mpd->b_blocknr = 0;
-                       }
-
                        mpd->next_page = page->index + 1;
                        logical = (sector_t) page->index <<
                                (PAGE_CACHE_SHIFT - inode->i_blkbits);
@@ -2975,9 +2971,6 @@ static int ext4_da_writepages(struct address_space *mapping,
                wbc->nr_to_write = desired_nr_to_write;
        }
 
-       mpd.wbc = wbc;
-       mpd.inode = mapping->host;
-
 retry:
        if (wbc->sync_mode == WB_SYNC_ALL)
                tag_pages_for_writeback(mapping, index, end);
@@ -3008,14 +3001,6 @@ retry:
                 * contiguous region of logical blocks that need
                 * blocks to be allocated by ext4 and submit them.
                 */
-               mpd.b_size = 0;
-               mpd.b_state = 0;
-               mpd.b_blocknr = 0;
-               mpd.first_page = 0;
-               mpd.next_page = 0;
-               mpd.io_done = 0;
-               mpd.pages_written = 0;
-               mpd.retval = 0;
                ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index);
                /*
                 * If we have a contiguous extent of pages and we