writeback: improve readability of the wb_writeback() continue/break logic

And throw some comments in there, too.

Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2009-09-23 19:32:26 +02:00
parent ae1b7f7d4b
commit 71fd05a887

View file

@ -750,29 +750,32 @@ static long wb_writeback(struct bdi_writeback *wb,
wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;
/*
* If we ran out of stuff to write, bail unless more_io got set
* If we consumed everything, see if we have more
*/
if (wbc.nr_to_write > 0) {
if (wbc.more_io) {
if (wbc.nr_to_write < MAX_WRITEBACK_PAGES)
continue;
/*
* Nothing written. Wait for some inode to
* become available for writeback. Otherwise
* we'll just busyloop.
*/
spin_lock(&inode_lock);
if (!list_empty(&wb->b_more_io)) {
inode = list_entry(
wb->b_more_io.prev,
struct inode, i_list);
inode_wait_for_writeback(inode);
}
spin_unlock(&inode_lock);
continue;
}
if (wbc.nr_to_write <= 0)
continue;
/*
* Didn't write everything and we don't have more IO, bail
*/
if (!wbc.more_io)
break;
/*
* Did we write something? Try for more
*/
if (wbc.nr_to_write < MAX_WRITEBACK_PAGES)
continue;
/*
* Nothing written. Wait for some inode to
* become available for writeback. Otherwise
* we'll just busyloop.
*/
spin_lock(&inode_lock);
if (!list_empty(&wb->b_more_io)) {
inode = list_entry(wb->b_more_io.prev,
struct inode, i_list);
inode_wait_for_writeback(inode);
}
spin_unlock(&inode_lock);
}
return wrote;