From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 25 Sep 2014 10:20:20 +0000
Subject: Re: [PATCH v2 01/22] PCI/MSI: Clean up struct msi_chip argument
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References: <1411614872-4009-1-git-send-email-wangyijing@huawei.com> <1411614872-4009-2-git-send-email-wangyijing@huawei.com> <20140925071536.GG12423@ulmo>
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To: Thierry Reding <thierry.reding@gmail.com>
Cc: Yijing Wang <wangyijing@huawei.com>, Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Xinwei Hu <huxinwei@huawei.com>, Wuyun <wuyun.wu@huawei.com>, linux-arm-kernel@lists.infradead.org, Russell King <linux@arm.linux.org.uk>, linux-arch@vger.kernel.org, arnab.basu@freescale.com, Bharat.Bhushan@freescale.com, x86@kernel.org, Arnd Bergmann <arnd@arndb.de>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, xen-devel@lists.xenproject.org, Joerg Roedel <joro@8bytes.org>, iommu@lists.linux-foundation.org, linux-mips@linux-mips.org, Benjamin Herrenschmidt <benh@kernel.crashing.org>, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, Sebastian Ott <sebott@linux.vnet.ibm.com>, Tony Luck <tony.luck@intel.com>, linux-ia64@vger.kernel.org, "David S. Miller" <davem@davemloft.net>, sparclinux@vger.kernel.org, Chris Metcalf <cmetcalf@tilera.com>, Ralf Baechle <ralf@linux-mips.org>, Lucas Stach <l.stach@pengutronix.de>, David Vrabel <david.vrabel@citrix.com>, Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>, Michael Ellerman <mpe@ellerman.id.au>, Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

On Thu, 25 Sep 2014, Thierry Reding wrote:

> On Thu, Sep 25, 2014 at 11:14:11AM +0800, Yijing Wang wrote:
> > Msi_chip functions setup_irq/teardown_irq rarely use msi_chip
> > argument.
> 
> That's not true. Out of the four drivers that you modify two use the
> parameter. And the two that don't probably should be using it too.
> 
> 50% is not "rarely". =)
> 
> >           We can look up msi_chip pointer by the device pointer
> > or irq number, so clean up msi_chip argument.
> 
> I don't like this particular change. The idea was to keep the API object
> oriented so that drivers wouldn't have to know where to get the MSI chip
> from. It also makes it more resilient against code reorganizations since
> the core code is the only place that needs to know where to get the chip
> from.

Right. We have the same thing in the irq_chip callbacks. All of them
take "struct irq_data", because it's already available in the core
code and it gives easy access to all information (chip, chipdata ...)
which is necessary for the callback implementations.

Thanks,

	tglx