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:   Wed, 10 Jul 2019 20:08:55 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Jan Kara <jack@suse.cz>
Cc:     Dan Williams <dan.j.williams@intel.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Boaz Harrosh <openosd@gmail.com>,
        stable <stable@vger.kernel.org>,
        Robert Barror <robert.barror@intel.com>,
        Seema Pandit <seema.pandit@intel.com>,
        linux-nvdimm <linux-nvdimm@lists.01.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] dax: Fix missed PMD wakeups
Message-ID: <20190711030855.GO32320@bombadil.infradead.org>
References: <CAPcyv4jgs5LTtTXR+2CyfbjJE85B_eoPFuXQsGBDnVMo41Jawg@mail.gmail.com>
 <20190703195302.GJ1729@bombadil.infradead.org>
 <CAPcyv4iPNz=oJyc_EoE-mC11=gyBzwMKbmj1ZY_Yna54=cC=Mg@mail.gmail.com>
 <20190704032728.GK1729@bombadil.infradead.org>
 <20190704165450.GH31037@quack2.suse.cz>
 <20190704191407.GM1729@bombadil.infradead.org>
 <CAPcyv4gUiDw8Ma9mvbW5BamQtGZxWVuvBW7UrOLa2uijrXUWaw@mail.gmail.com>
 <20190705191004.GC32320@bombadil.infradead.org>
 <CAPcyv4jVARa38Qc4NjQ04wJ4ZKJ6On9BbJgoL95wQqU-p-Xp_w@mail.gmail.com>
 <20190710190204.GB14701@quack2.suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190710190204.GB14701@quack2.suse.cz>
User-Agent: Mutt/1.11.4 (2019-03-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Jul 10, 2019 at 09:02:04PM +0200, Jan Kara wrote:
> @@ -848,7 +853,7 @@ static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
>  	if (unlikely(dax_is_locked(entry))) {
>  		void *old_entry = entry;
>  
> -		entry = get_unlocked_entry(xas);
> +		entry = get_unlocked_entry(xas, 0);
>  
>  		/* Entry got punched out / reallocated? */
>  		if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))

I'm not sure about this one.  Are we sure there will never be a dirty
PMD entry?  Even if we can't create one today, it feels like a bit of
a landmine to leave for someone who creates one in the future.