Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 21 Apr 2023 15:30:17 -0700
From:   Luis Chamberlain <mcgrof@kernel.org>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Matthew Wilcox <willy@infradead.org>, agk@redhat.com,
        snitzer@kernel.org, philipp.reisner@linbit.com,
        lars.ellenberg@linbit.com, christoph.boehmwalder@linbit.com,
        hch@infradead.org, djwong@kernel.org, minchan@kernel.org,
        senozhatsky@chromium.org, patches@lists.linux.dev,
        linux-block@vger.kernel.org, linux-mm@kvack.org,
        linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        dm-devel@redhat.com, drbd-dev@lists.linbit.com,
        linux-kernel@vger.kernel.org, hare@suse.de, p.raghav@samsung.com,
        da.gomez@samsung.com, kbusch@kernel.org
Subject: Re: [PATCH 3/5] iomap: simplify iomap_init() with PAGE_SECTORS
Message-ID: <ZEMOeb9Bt60jxV+d@bombadil.infradead.org>
References: <20230421195807.2804512-1-mcgrof@kernel.org>
 <20230421195807.2804512-4-mcgrof@kernel.org>
 <ZELuiBNNHTk4EdxH@casper.infradead.org>
 <ZEMH9h/cd9Cp1t+X@bombadil.infradead.org>
 <47688c1d-9cf1-3e08-1f1d-a051b25d010e@kernel.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <47688c1d-9cf1-3e08-1f1d-a051b25d010e@kernel.dk>
Sender: Luis Chamberlain <mcgrof@infradead.org>
Precedence: bulk

On Fri, Apr 21, 2023 at 04:24:57PM -0600, Jens Axboe wrote:
> On 4/21/23 4:02 PM, Luis Chamberlain wrote:
> > On Fri, Apr 21, 2023 at 09:14:00PM +0100, Matthew Wilcox wrote:
> >> On Fri, Apr 21, 2023 at 12:58:05PM -0700, Luis Chamberlain wrote:
> >>> Just use the PAGE_SECTORS generic define. This produces no functional
> >>> changes. While at it use left shift to simplify this even further.
> >>
> >> How is FOO << 2 simpler than FOO * 4?
> >>
> >>> -	return bioset_init(&iomap_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE),
> >>> +	return bioset_init(&iomap_ioend_bioset, PAGE_SECTORS << 2,
> > 
> > We could just do:
> > 
> > 
> > -	return bioset_init(&iomap_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE),
> > +	return bioset_init(&iomap_ioend_bioset, 4 * PAGE_SECTORS,
> > 
> > The shift just seemed optimal if we're just going to change it.
> 
> It's going to generate the same code, but the multiplication is arguably
> easier to read (or harder to misread).

Then let's stick with the 4 * PAGE_SECTORS. Let me know if you need another
patch.

  Luis