From mboxrd@z Thu Jan  1 00:00:00 1970
From: Omar Sandoval <osandov@osandov.com>
Subject: Re: [RFC PATCH v2 5/5] btrfs: implement RWF_ENCODED writes
Date: Mon, 21 Oct 2019 11:05:22 -0700
Message-ID: <20191021180522.GA81648@vader>
References: <cover.1571164762.git.osandov@fb.com>
 <904de93d9bbe630aff7f725fd587810c6eb48344.1571164762.git.osandov@fb.com>
 <0da91628-7f54-7d24-bf58-6807eb9535a5@suse.com>
 <20191018225513.GD59713@vader>
 <20191021131452.GH3001@twin.jikos.cz>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Return-path: <linux-btrfs-owner@vger.kernel.org>
Content-Disposition: inline
In-Reply-To: <20191021131452.GH3001@twin.jikos.cz>
Sender: linux-btrfs-owner@vger.kernel.org
To: dsterba@suse.cz, Nikolay Borisov <nborisov@suse.com>, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, kernel-team@fb.com, Dave Chinner <david@fromorbit.com>, Jann Horn <jannh@google.com>, linux-api@vger.kernel.org
List-Id: linux-api@vger.kernel.org

On Mon, Oct 21, 2019 at 03:14:52PM +0200, David Sterba wrote:
> On Fri, Oct 18, 2019 at 03:55:13PM -0700, Omar Sandoval wrote:
> > > > +	nr_pages = (disk_num_bytes + PAGE_SIZE - 1) >> PAGE_SHIFT;
> > > 
> > > nit: nr_pages = DIV_ROUND_UP(disk_num_bytes, PAGE_SIZE)
> > 
> > disk_num_bytes is a u64, so that would expand to a 64-bit division. The
> > compiler is probably smart enough to optimize it to a shift, but I
> > didn't want to rely on that, because that would cause build failures on
> > 32-bit.
> 
> There are several DIV_ROUND_UP(u64, PAGE_SIZE) in btrfs code, no build
> brekages have been reported so far, you can use it.

Good to know, I'll fix both places I'm doing this, then.