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From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Tue, 1 Jun 2021 15:11:47 +0200
Message-ID: <CAJfpeguSnA-At8Jca0Ge0aytC22Gb5YmKpxbEy82rR7btczh5Q@mail.gmail.com>
Subject: Re: [REPOST PATCH v4 3/5] kernfs: switch kernfs to use an rwsem
To:     Ian Kent <raven@themaw.net>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Tejun Heo <tj@kernel.org>, Eric Sandeen <sandeen@sandeen.net>,
        Fox Chen <foxhlchen@gmail.com>,
        Brice Goglin <brice.goglin@gmail.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Rick Lindsley <ricklind@linux.vnet.ibm.com>,
        David Howells <dhowells@redhat.com>,
        Marcelo Tosatti <mtosatti@redhat.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Fri, 28 May 2021 at 08:34, Ian Kent <raven@themaw.net> wrote:
>
> The kernfs global lock restricts the ability to perform kernfs node
> lookup operations in parallel during path walks.
>
> Change the kernfs mutex to an rwsem so that, when opportunity arises,
> node searches can be done in parallel with path walk lookups.

I don't see how this could have any drawbacks.

Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>