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, 13 Jul 2020 17:41:45 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Chris Down <chris@chrisdown.name>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Amir Goldstein <amir73il@gmail.com>,
        Jeff Layton <jlayton@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Tejun Heo <tj@kernel.org>, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@fb.com
Subject: Re: [PATCH v6 1/2] tmpfs: Per-superblock i_ino support
Message-ID: <20200713164145.GY12769@casper.infradead.org>
References: <cover.1594656618.git.chris@chrisdown.name>
 <2cddd4498ba1db1c7a3831d47b9db0d063746a3b.1594656618.git.chris@chrisdown.name>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <2cddd4498ba1db1c7a3831d47b9db0d063746a3b.1594656618.git.chris@chrisdown.name>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Jul 13, 2020 at 05:15:39PM +0100, Chris Down wrote:
> +#define SHMEM_INO_BATCH 1024U
...
> +		if (unlikely((ino & ~SHMEM_INO_BATCH) == 0)) {

I don't think that works.  I think you meant to write ~(SHMEM_INO_BATCH - 1).
Or just ino % SHMEM_INO_BATCH which works even for non-power-of-two.