From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [RFC] ->get_link(), ->put_link() and cookies
Date: Sun, 3 Jan 2016 20:21:21 +0000 [thread overview]
Message-ID: <20160103202121.GM9938@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFx4H1uuDU9JST26FOwi6LBU9nJUPYvX7479DEk1tVaZ3w@mail.gmail.com>
On Sun, Jan 03, 2016 at 11:53:21AM -0800, Linus Torvalds wrote:
> On Thu, Dec 31, 2015 at 10:36 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> > In cases when we need to pin the symlink body in some manner, we
> > need to undo whatever we'd done once the caller is done with the body.
> > That went through several variants, the latest (in -next right now) being
> > "have non-NULL ->put_link() and leave an argument for it in void *cookie,
> > address of which is passed to ->get_link()".
>
> The series looks ok to me, even if I still am not a fan of the cookie.
> I suspect the remaining users could easily embed the returned string
> at the end of a structure, and get their data with container_of(). It
> would complicate their unusual behavior for sure, but make the common
> case much more understandable.
>
> Oh well. I won't insist - it may be too painful to be worth it. And
> it's a fairly separate issue anyway.
>
> So no objections to this series.
Just to make sure - that does include 13/13, presumably? IOW, ->put_link()
is gone and the final calling conventions for ->get_link() are
const char *(*get_link)(struct dentry *dentry,
struct inode *inode,
struct delayed_call *done);
with dentry == NULL <=> call in RCU mode, ERR_PTR(-E...) returned on error
and set_delayed_call(done, destructor, arg) done if destructor(arg) should
be done once pathname resolution is through with the body returned by
->get_link().
next prev parent reply other threads:[~2016-01-03 20:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-01 6:36 [RFC] ->get_link(), ->put_link() and cookies Al Viro
2016-01-01 6:38 ` [PATCH 01/13] switch befs long symlinks to page_symlink_operations Al Viro
2016-01-01 6:38 ` [PATCH 02/13] logfs: don't duplicate page_symlink_inode_operations Al Viro
2016-01-01 6:38 ` [PATCH 03/13] udf: " Al Viro
2016-01-05 16:27 ` Jan Kara
2016-01-01 6:38 ` [PATCH 04/13] ufs: get rid of ->setattr() for symlinks Al Viro
2016-01-01 6:38 ` [PATCH 05/13] namei: page_getlink() and page_follow_link_light() are the same thing Al Viro
2016-01-01 6:38 ` [PATCH 06/13] don't put symlink bodies in pagecache into highmem Al Viro
2016-01-01 6:38 ` [PATCH 07/13] replace ->follow_link() with new method that could stay in RCU mode Al Viro
2016-01-01 6:38 ` [PATCH 08/13] teach page_get_link() to work " Al Viro
2016-01-01 6:38 ` [PATCH 09/13] teach shmem_get_link() " Al Viro
2016-01-01 6:38 ` [PATCH 10/13] teach proc_self_get_link()/proc_thread_self_get_link() " Al Viro
2016-01-01 6:38 ` [PATCH 11/13] teach nfs_get_link() " Al Viro
2016-01-01 6:38 ` [PATCH 12/13] kill free_page_put_link() Al Viro
2016-01-01 6:38 ` [PATCH 13/13] switch ->get_link() to delayed_call, kill ->put_link() Al Viro
2016-01-03 19:53 ` [RFC] ->get_link(), ->put_link() and cookies Linus Torvalds
2016-01-03 20:21 ` Al Viro [this message]
2016-01-03 20:41 ` Linus Torvalds
2016-01-03 21:40 ` Al Viro
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