From: Gavin Shan <gwshan@linux.vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@au1.ibm.com>
Cc: aik@au1.ibm.com, Wei Yang <weiyang@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org,
Gavin Shan <gwshan@linux.vnet.ibm.com>
Subject: Re: [PATCH 1/2] powerpc/powernv: clear the refcount for pci_dev on powernv platform
Date: Wed, 23 Apr 2014 09:00:33 +1000 [thread overview]
Message-ID: <20140422230033.GA12208@shangw> (raw)
In-Reply-To: <1398155109.19682.89.camel@pasglop>
On Tue, Apr 22, 2014 at 06:25:09PM +1000, Benjamin Herrenschmidt wrote:
>On Tue, 2014-04-22 at 15:44 +0800, Wei Yang wrote:
>> So this patch(the 2nd one) doesn't contribute to clear the warning and
>> error.
>> Only the first patch did it. Please ignore this one.
>
>But is it correct ? It's not right to keep a refcount elevated if we
>don't have to.
>
>Gavin, can you get to the bottom of that refcount business ?
>
Ben, "struct pci_dn::pcidev" was used by EEH originally. We don't
use it any more. So it can be removed.
Currently, EEH has following 4 functions to do conversion from
one to another. None of them relies on "struct pci_dn::pcidev".
of_node_to_eeh_dev() device_node -> pci_dn -> eeh_dev
pci_dev_to_eeh_dev() pci_dev -> device -> archdata -> eeh_dev
eeh_dev_to_of_node() eeh_dev -> device_node
eeh_dev_to_pci_dev() eeh_dev -> pci_dev
The side effect of holding pci_dev refcount is the pci_dev, eeh_dev,
eeh_pe instance can't be free'ed during fully hotplug though EEH can
survive. It's reasonable to remove it.
Thanks,
Gavin
next prev parent reply other threads:[~2014-04-22 23:00 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-21 2:25 [PATCH 1/2] powerpc/powernv: clear the refcount for pci_dev on powernv platform Wei Yang
2014-04-21 2:25 ` [PATCH 2/2] powerpc/powernc: revert part of commit d905c5df(PPC: POWERNV: move iommu_add_device earlier) Wei Yang
2014-04-21 3:37 ` Benjamin Herrenschmidt
2014-04-21 5:22 ` Wei Yang
2014-04-21 6:11 ` Wei Yang
2014-04-21 3:35 ` [PATCH 1/2] powerpc/powernv: clear the refcount for pci_dev on powernv platform Benjamin Herrenschmidt
2014-04-21 6:03 ` Wei Yang
2014-04-21 23:34 ` Gavin Shan
2014-04-22 7:44 ` Wei Yang
2014-04-22 8:25 ` Benjamin Herrenschmidt
2014-04-22 9:44 ` Wei Yang
2014-04-22 23:00 ` Gavin Shan [this message]
2014-04-23 0:26 ` Benjamin Herrenschmidt
2014-04-23 1:56 ` Wei Yang
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