Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 30 Aug 2021 08:32:05 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     Li Zhijian <lizhijian@cn.fujitsu.com>
Cc:     linux-mm@kvack.org, linux-rdma@vger.kernel.org,
        akpm@linux-foundation.org, jglisse@redhat.com, jgg@ziepe.ca,
        hch@infradead.org, yishaih@nvidia.com,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v2] mm/hmm: bypass devmap pte when all pfn requested
 flags are fulfilled
Message-ID: <YSyJdUirSGv01nTy@infradead.org>
References: <20210828010441.3702-1-lizhijian@cn.fujitsu.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210828010441.3702-1-lizhijian@cn.fujitsu.com>
Precedence: bulk

On Sat, Aug 28, 2021 at 09:04:41AM +0800, Li Zhijian wrote:
> +	if (!pte_devmap(pte) && pte_special(pte) &&
> +	    !is_zero_pfn(pte_pfn(pte))) {

Maybe this is a little too superficial and nitpicky, but I find the
ordering of the checks a little strange.  Why not do the pte_special
first and then the exlusions from it later?