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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	David Miller <davem@davemloft.net>,
	David Ahern <david.ahern@oracle.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"sparclinux@vger.kernel.org" <sparclinux@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH 3/3] PCI: Set pref for mem64 resource of pcie device
Date: Thu, 09 Apr 2015 18:56:55 +1000	[thread overview]
Message-ID: <1428569815.18187.71.camel@kernel.crashing.org> (raw)
In-Reply-To: <CAE9FiQUnpKmQmeHvBpk1t-NSAPuWAC9tX7LXeGpVR1w78i658g@mail.gmail.com>

On Wed, 2015-04-08 at 21:11 -0700, Yinghai Lu wrote:
> That way should be more intrusive to current code, as we are using
> type_mask checking to share the code among
> parent(pref)/child(pref), parent(no-pref)/child(pref), and
> parent(no-pref)/child(pref)

That's fine, as long as the helper knows which one is the parent and
which one is the child.

In fact, as "cute" as the mask trick is, I think it would generally make
the code more self explanatory if it explicitly tested for the
combinations that are supported, ie something like

	if (parent_is_pref && !child_is_pref && child->pcie_only)
		...
	else if (!parent_is_pref)
		...
etc...

The impact in performance would be in the noise and the logic of the
algorithm a LOT more explicit.

Cheers,
Ben.



  reply	other threads:[~2015-04-09  8:56 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1427857069-6789-1-git-send-email-yinghai@kernel.org>
2015-04-01  2:57 ` [PATCH 1/3] PCI: Introduce pci_bus_addr_t Yinghai Lu
2015-04-03 18:59   ` Bjorn Helgaas
2015-04-03 19:05     ` David Miller
2015-04-04  3:40     ` Yinghai Lu
2015-04-03 19:32   ` Bjorn Helgaas
2015-04-03 20:52     ` Bjorn Helgaas
2015-04-04  3:34       ` Yinghai Lu
2015-04-04 12:46         ` Bjorn Helgaas
2015-04-04 19:48           ` Rob Herring
2015-04-05  3:25             ` Bjorn Helgaas
2015-04-06 13:05               ` Rob Herring
2015-04-01  2:57 ` [PATCH 2/3] sparc/PCI: Add mem64 resource parsing for root bus Yinghai Lu
2015-04-03 20:46   ` Bjorn Helgaas
2015-04-01  2:57 ` [PATCH 3/3] PCI: Set pref for mem64 resource of pcie device Yinghai Lu
2015-04-06 22:06   ` Bjorn Helgaas
2015-04-06 22:35     ` Yinghai Lu
2015-04-06 22:49       ` Bjorn Helgaas
2015-04-07  1:13         ` Yinghai Lu
2015-04-07  3:43           ` Bjorn Helgaas
2015-04-07  5:23             ` Yinghai Lu
2015-04-07 12:18               ` Bjorn Helgaas
2015-04-07  0:35     ` David Miller
2015-04-07 16:48       ` Bjorn Helgaas
2015-04-08 15:47         ` Bjorn Helgaas
2015-04-08 16:08           ` David Miller
2015-04-08 21:12           ` Benjamin Herrenschmidt
2015-04-09  0:06             ` Yinghai Lu
2015-04-09  3:17               ` Benjamin Herrenschmidt
2015-04-09  4:11                 ` Yinghai Lu
2015-04-09  8:56                   ` Benjamin Herrenschmidt [this message]
2015-04-09  4:26                 ` Bjorn Helgaas
2015-04-09  8:54                   ` Benjamin Herrenschmidt
2015-04-09 18:31                     ` Yinghai Lu
2015-04-09 23:31                       ` Benjamin Herrenschmidt
2015-04-10  4:13                         ` Yinghai Lu

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