ext4: simplify list handling in ext4_do_flush_completed_IO()
The function splices i_completed_io_list to its private list
first. From that moment on we don't need any lock for working with
io_end structures because all io_end structure on the list are only
our own. So we can remove the other two lists in the function and free
io_end immediately after we are done with it.
CC: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index a029017..3fb385c 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -160,14 +160,11 @@
static int ext4_do_flush_completed_IO(struct inode *inode)
{
ext4_io_end_t *io;
- struct list_head unwritten, complete, to_free;
+ struct list_head unwritten;
unsigned long flags;
struct ext4_inode_info *ei = EXT4_I(inode);
int err, ret = 0;
- INIT_LIST_HEAD(&complete);
- INIT_LIST_HEAD(&to_free);
-
spin_lock_irqsave(&ei->i_completed_io_lock, flags);
dump_completed_IO(inode);
list_replace_init(&ei->i_completed_io_list, &unwritten);
@@ -181,20 +178,7 @@
err = ext4_end_io(io);
if (unlikely(!ret && err))
ret = err;
-
- list_add_tail(&io->list, &complete);
- }
- spin_lock_irqsave(&ei->i_completed_io_lock, flags);
- while (!list_empty(&complete)) {
- io = list_entry(complete.next, ext4_io_end_t, list);
io->flag &= ~EXT4_IO_END_UNWRITTEN;
- list_move(&io->list, &to_free);
- }
- spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
-
- while (!list_empty(&to_free)) {
- io = list_entry(to_free.next, ext4_io_end_t, list);
- list_del_init(&io->list);
ext4_free_io_end(io);
}
return ret;