Re: [PATCH 0/2] ext2: Convert kmap to kmap_local_page

From: Jan Kara
Date: Wed Mar 31 2021 - 08:05:53 EST


Hi Ira!

On Sun 28-03-21 23:54:00, ira.weiny@xxxxxxxxx wrote:
> From: Ira Weiny <ira.weiny@xxxxxxxxx>
>
> kmap is inefficient and can be abused so it is being phased out in favor of
> kmap_local_page where possible.
>
> ext2 uses kmap in ext2_[get|put]_page(). All of the calls to
> ext2_[get|put]_page() occur in single threads so it is perfectly safe and
> preferable to use kmap_local_page().
>
> This series has a clean up which matches ext2_put_page() with ext2_dotdot() and
> ext2_find_entry(). Those calls use ext2_get_page() to map the page prior to
> returning it to their callers. And they document that ext2_put_page() should
> be matched up with them. This was the case but the ext2_put_page() calls were
> hidden in other functions. We lift the ext2_put_page() calls to match up to
> the functions where ext2_dotdot() and ext2_find_entry() are called.
>
> After that clean up convert ext2_[get|put]_page() to kmap and adjust for
> kunmap_local() requiring the page address.
>
> Nesting of kmap_local_page() calls is maintained with minor changes.

Pulled into my tree. Thanks!

Honza

>
> Ira Weiny (2):
> ext2: Match up ext2_put_page() with ext2_dotdot() and
> ext2_find_entry()
> fs/ext2: Replace kmap() with kmap_local_page()
>
> fs/ext2/dir.c | 94 +++++++++++++++++++++++++++++++------------------
> fs/ext2/ext2.h | 12 ++++---
> fs/ext2/namei.c | 34 +++++++++++-------
> 3 files changed, 89 insertions(+), 51 deletions(-)
>
> --
> 2.28.0.rc0.12.gb6a658bd00c9
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR