From: Arnd Bergmann <arnd@arndb.de>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>,
Lucas De Marchi <lucas.demarchi@profusion.mobi>,
Paul Mundt <lethal@linux-sh.org>,
Jesse Barnes <jbarnes@virtuousgeek.org>,
"David S. Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-arch@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH-RFC 1/2] tile: don't panic on iomap
Date: Wed, 30 Nov 2011 15:49:57 +0000 [thread overview]
Message-ID: <201111301549.57430.arnd@arndb.de> (raw)
In-Reply-To: <20111130143122.GC21413@redhat.com>
On Wednesday 30 November 2011, Michael S. Tsirkin wrote:
> On Wed, Nov 30, 2011 at 02:04:41PM +0000, Arnd Bergmann wrote:
>
> > Ah, right. I didn't realize that the generic pci_iomap still attempts
> > to call ioport_map(). It would probably make sense to enclose
> > the ioport_map() call in pci_iomap() inside of #ifdef CONFIG_HAS_IOPORT.
> > It's not exactly beautiful, but probably the most correct solution
> > so that we can make any call to ioport_map() a build-time error on
> > architectures that set CONFIG_NO_IOPORT.
>
> I'm not sure why do you want to do that.
>
The problem is that any definition of ioport_map on architectures
that can't do it is potentially harmful. Calling panic() is
bad style as you pointed out, but simply returning NULL can
also be harmful because it's likely that some drivers are written
under the (false) assumption that ioport_map can never fail.
Getting a build-time error would be more helpful here IMHO.
Arnd
next prev parent reply other threads:[~2011-11-30 15:50 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-29 18:54 [PATCH-RFC 0/2] tile: switch to generic pci_iomap Michael S. Tsirkin
2011-11-29 18:54 ` [PATCH-RFC 1/2] tile: don't panic on iomap Michael S. Tsirkin
2011-11-29 18:54 ` Michael S. Tsirkin
2011-11-29 21:04 ` Bjorn Helgaas
2011-11-29 21:04 ` Bjorn Helgaas
2011-11-30 7:04 ` Michael S. Tsirkin
2011-11-29 22:05 ` Arnd Bergmann
2011-11-29 22:05 ` Arnd Bergmann
2011-11-30 7:13 ` Michael S. Tsirkin
2011-11-30 9:09 ` Arnd Bergmann
2011-11-30 9:09 ` Arnd Bergmann
2011-11-30 11:59 ` Michael S. Tsirkin
2011-11-30 14:04 ` Arnd Bergmann
2011-11-30 14:04 ` Arnd Bergmann
2011-11-30 14:31 ` Michael S. Tsirkin
2011-11-30 15:49 ` Arnd Bergmann [this message]
2011-11-30 15:59 ` Michael S. Tsirkin
2011-11-30 18:32 ` Arnd Bergmann
2011-11-30 18:32 ` Arnd Bergmann
2011-12-01 17:59 ` [PATCH] lib/devres.c: allow specifying NO_IOPORT while using PCI Chris Metcalf
2011-12-01 17:59 ` Chris Metcalf
2011-12-01 18:44 ` Tejun Heo
2011-12-01 18:44 ` Tejun Heo
2011-12-01 18:48 ` Chris Metcalf
2011-12-01 22:47 ` Arnd Bergmann
2011-12-01 22:47 ` Arnd Bergmann
2011-12-02 18:48 ` Chris Metcalf
2011-12-02 18:48 ` Chris Metcalf
2011-12-05 15:14 ` Arnd Bergmann
2011-12-05 20:08 ` Chris Metcalf
2011-12-05 20:08 ` Chris Metcalf
2011-11-30 9:08 ` [PATCH-RFC 1/2 v2] tile: don't panic on iomap Michael S. Tsirkin
2011-11-30 9:08 ` Michael S. Tsirkin
2011-11-29 18:54 ` [PATCH-RFC 2/2] tile: switch to GENERIC_PCI_IOMAP Michael S. Tsirkin
2011-11-29 18:54 ` Michael S. Tsirkin
2011-11-30 21:19 ` Chris Metcalf
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