On Tue, Jan 19, 2021 at 04:51:45PM +0100, David Sterba wrote: > On Tue, Jan 19, 2021 at 06:54:28AM +0800, Qu Wenruo wrote: > > On 2021/1/19 上午6:46, David Sterba wrote: > > > On Sat, Jan 16, 2021 at 03:15:18PM +0800, Qu Wenruo wrote: > > >> + return; > > >> + > > >> + subpage = (struct btrfs_subpage *)detach_page_private(page); > > >> + ASSERT(subpage); > > >> + kfree(subpage); > > >> +} > > >> diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h > > >> new file mode 100644 > > >> index 000000000000..96f3b226913e > > >> --- /dev/null > > >> +++ b/fs/btrfs/subpage.h > > >> @@ -0,0 +1,31 @@ > > >> +/* SPDX-License-Identifier: GPL-2.0 */ > > >> + > > >> +#ifndef BTRFS_SUBPAGE_H > > >> +#define BTRFS_SUBPAGE_H > > >> + > > >> +#include <linux/spinlock.h> > > >> +#include "ctree.h" > > > > > > So subpage.h would pull the whole ctree.h, that's not very nice. If > > > anything, the .c could include ctree.h because there are lots of the > > > common structure and function definitions, but not the .h. This creates > > > unnecessary include dependencies. > > > > > > Any pointer type you'd need in structures could be forward declared. > > > > Unfortunately, the main needed pointer is fs_info, and we're accessing > > it pretty frequently (mostly for sector/node size). > > > > I don't believe forward declaration would help in this case. > > I've looked at the final subpage.h and you add way too many static > inlines that don't seem to be necessary for the reasons the static > inlines are supposed to be used.
The only file that includes subpage.h is extent_io.c, so as long as it stays like that it's manageable. But untangling the include hell still needs to hapen some day and new code that makes it harder worries me.