Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 21 Dec 2018 11:02:43 -0600
From:   Dennis Zhou <dennis@kernel.org>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Dennis Zhou <dennis@kernel.org>, kernel-team@fb.com,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] blkcg: add rcu lock to bio_clone_blkg_association()
Message-ID: <20181221170243.GA17140@dennisz-mbp>
References: <20181221145441.13814-1-dennis@kernel.org>
 <f1dacd9e-7c3d-44e5-aff1-923d9e7a374c@kernel.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <f1dacd9e-7c3d-44e5-aff1-923d9e7a374c@kernel.dk>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Dec 21, 2018 at 08:26:02AM -0700, Jens Axboe wrote:
> On 12/21/18 7:54 AM, Dennis Zhou wrote:
> > I cleaned up blkg_tryget_closest() to require rcu_read_lock() earlier.
> > However, this was a subtle case too which clearly was too subtle for me.
> > The idea was the src bio should be holding a ref to the blkg so rcu
> > wasn't technically needed. If it doesn't hold a ref, it should be %NULL
> > and the blkg->parent pointers are unused.
> > 
> > This adds the appropriate read lock in bio_clone_blkg_association().
> 
> Shall I just fold this with the previous? I staged it in a
> later-in-merge-cycle branch, so that's not an issue to amend.
> 

Yeah that would be great!

Thanks,
Dennis