linux-kernel - Re: [PATCH 1/1] fs/ext2: Avoid page_address on pages returned by ext2_get

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Message-ID: <20210714090013.GA9457@quack2.suse.cz>
Date:   Wed, 14 Jul 2021 11:00:13 +0200
From:   Jan Kara <jack@...e.cz>
To:     Javier Pello <javier.pello@...c.es>
Cc:     Jan Kara <jack@...e.cz>, Jan Kara <jack@...e.com>,
        linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ira Weiny <ira.weiny@...el.com>
Subject: Re: [PATCH 1/1] fs/ext2: Avoid page_address on pages returned by
 ext2_get_page

On Tue 13-07-21 19:33:19, Javier Pello wrote:
> On Tue, 13 Jul 2021 18:30:18, Jan Kara wrote:
> > > @@ -584,16 +584,16 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode)
> > >   * ext2_delete_entry deletes a directory entry by merging it with the
> > >   * previous entry. Page is up-to-date.
> > >   */
> > > -int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
> > > +int ext2_delete_entry (struct ext2_dir_entry_2 *dir, struct page *page,
> > > +                     void *kaddr)
> > 
> > Why not have 'kaddr' as char *. We type it to char * basically everywhere
> > anyway.
> 
> I thought about that, as well, but in the end I leaned towards void *
> because it is a generic pointer, conceptually. Would you rather have it
> be char *?

Well, it depends on how you look at it. We can also think of kaddr as a
start of buffer 'dir' is pointing to. Anyway given this is not some generic
function but a very targetted one with only a few call sites I'd just lean
towards making our life easy and making kaddr char *.

								Honza
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR