writeback: elevate queue_io() into wb_writeback()

Code refactor for more logical code layout.
No behavior change.

- remove the mis-named __writeback_inodes_sb()

- wb_writeback()/writeback_inodes_wb() will decide when to queue_io()
  before calling __writeback_inodes_wb()

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 36a30917e0dc6909c49c563b3c6366980a47f50f..565b1fd15be614b88c1d680f71c36aa1dd2ba38d 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -580,17 +580,13 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
        return 1;
 }
 
-void writeback_inodes_wb(struct bdi_writeback *wb,
-               struct writeback_control *wbc)
+static void __writeback_inodes_wb(struct bdi_writeback *wb,
+                                 struct writeback_control *wbc)
 {
        int ret = 0;
 
        if (!wbc->wb_start)
                wbc->wb_start = jiffies; /* livelock avoidance */
-       spin_lock(&wb->list_lock);
-
-       if (list_empty(&wb->b_io))
-               queue_io(wb, wbc->older_than_this);
 
        while (!list_empty(&wb->b_io)) {
                struct inode *inode = wb_inode(wb->b_io.prev);
@@ -606,19 +602,16 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
                if (ret)
                        break;
        }
-       spin_unlock(&wb->list_lock);
        /* Leave any unwritten inodes on b_io */
 }
 
-static void __writeback_inodes_sb(struct super_block *sb,
-               struct bdi_writeback *wb, struct writeback_control *wbc)
+void writeback_inodes_wb(struct bdi_writeback *wb,
+               struct writeback_control *wbc)
 {
-       WARN_ON(!rwsem_is_locked(&sb->s_umount));
-
        spin_lock(&wb->list_lock);
        if (list_empty(&wb->b_io))
                queue_io(wb, wbc->older_than_this);
-       writeback_sb_inodes(sb, wb, wbc, true);
+       __writeback_inodes_wb(wb, wbc);
        spin_unlock(&wb->list_lock);
 }
 
@@ -685,7 +678,7 @@ static long wb_writeback(struct bdi_writeback *wb,
         * The intended call sequence for WB_SYNC_ALL writeback is:
         *
         *      wb_writeback()
-        *          __writeback_inodes_sb()     <== called only once
+        *          writeback_sb_inodes()       <== called only once
         *              write_cache_pages()     <== called once for each inode
         *                   (quickly) tag currently dirty pages
         *                   (maybe slowly) sync all tagged pages
@@ -694,6 +687,7 @@ static long wb_writeback(struct bdi_writeback *wb,
                write_chunk = LONG_MAX;
 
        wbc.wb_start = jiffies; /* livelock avoidance */
+       spin_lock(&wb->list_lock);
        for (;;) {
                /*
                 * Stop writeback when nr_pages has been consumed
@@ -730,10 +724,12 @@ static long wb_writeback(struct bdi_writeback *wb,
                wbc.inodes_written = 0;
 
                trace_wbc_writeback_start(&wbc, wb->bdi);
+               if (list_empty(&wb->b_io))
+                       queue_io(wb, wbc.older_than_this);
                if (work->sb)
-                       __writeback_inodes_sb(work->sb, wb, &wbc);
+                       writeback_sb_inodes(work->sb, wb, &wbc, true);
                else
-                       writeback_inodes_wb(wb, &wbc);
+                       __writeback_inodes_wb(wb, &wbc);
                trace_wbc_writeback_written(&wbc, wb->bdi);
 
                work->nr_pages -= write_chunk - wbc.nr_to_write;
@@ -761,7 +757,6 @@ static long wb_writeback(struct bdi_writeback *wb,
                 * become available for writeback. Otherwise
                 * we'll just busyloop.
                 */
-               spin_lock(&wb->list_lock);
                if (!list_empty(&wb->b_more_io))  {
                        inode = wb_inode(wb->b_more_io.prev);
                        trace_wbc_writeback_wait(&wbc, wb->bdi);
@@ -769,8 +764,8 @@ static long wb_writeback(struct bdi_writeback *wb,
                        inode_wait_for_writeback(inode, wb);
                        spin_unlock(&inode->i_lock);
                }
-               spin_unlock(&wb->list_lock);
        }
+       spin_unlock(&wb->list_lock);
 
        return wrote;
 }