From: Alexey Kardashevskiy <aik@au1•ibm.com>
To: Nishanth Aravamudan <nacc@linux•vnet.ibm.com>,
Michael Ellerman <mpe@ellerman•id.au>
Cc: linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH] pseries/iommu: remove iommu device references via bus notifier
Date: Fri, 20 Feb 2015 12:17:50 +1100 [thread overview]
Message-ID: <54E68B3E.5020707@au1.ibm.com> (raw)
In-Reply-To: <20150219184103.GB13745@linux.vnet.ibm.com>
On 02/20/2015 05:41 AM, Nishanth Aravamudan wrote:
> After d905c5df9aef ("PPC: POWERNV: move iommu_add_device earlier"), the
> refcnt on the kobject backing the IOMMU group for a PCI device is
> elevated by each call to pci_dma_dev_setup_pSeriesLP() (via
> set_iommu_table_base_and_group). When we go to dlpar a multi-function
> PCI device out:
>
> iommu_reconfig_notifier ->
> iommu_free_table ->
> iommu_group_put
> BUG_ON(tbl->it_group)
>
> We trip this BUG_ON, because there are still references on the table, so
> it is not freed. Fix this by also adding a bus notifier identical to
> PowerNV for pSeries. Tested a remove -> add -> remove cycle without
> issue where it always hit the BUG_ON without the changes.
>
> Fixes: d905c5df9aef ("PPC: POWERNV: move iommu_add_device earlier")
> Signed-off-by: Nishanth Aravamudan <nacc@linux•vnet.ibm.com>
> Cc: stable@kernel•org (3.13+)
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs•ru>
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 1d3d52dc3ff3..f77fb02f4710 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -1340,3 +1340,31 @@ static int __init disable_multitce(char *str)
> }
>
> __setup("multitce=", disable_multitce);
> +
> +static int tce_iommu_bus_notifier(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct device *dev = data;
> +
> + switch (action) {
> + case BUS_NOTIFY_ADD_DEVICE:
> + return iommu_add_device(dev);
> + case BUS_NOTIFY_DEL_DEVICE:
> + if (dev->iommu_group)
> + iommu_del_device(dev);
> + return 0;
> + default:
> + return 0;
> + }
> +}
> +
> +static struct notifier_block tce_iommu_bus_nb = {
> + .notifier_call = tce_iommu_bus_notifier,
> +};
> +
> +static int __init tce_iommu_bus_notifier_init(void)
> +{
> + bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
> + return 0;
> +}
> +machine_subsys_initcall_sync(pseries, tce_iommu_bus_notifier_init);
>
--
Alexey Kardashevskiy
IBM OzLabs, LTC Team
e-mail: aik@au1•ibm.com
notes: Alexey Kardashevskiy/Australia/IBM
next prev parent reply other threads:[~2015-02-20 1:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-19 18:41 [PATCH] pseries/iommu: remove iommu device references via bus notifier Nishanth Aravamudan
2015-02-20 1:17 ` Alexey Kardashevskiy [this message]
2015-02-20 4:31 ` Michael Ellerman
2015-02-21 19:00 ` [PATCH v2] " Nishanth Aravamudan
2015-02-23 2:27 ` [v2] " Michael Ellerman
2015-02-23 18:54 ` Nishanth Aravamudan
2015-02-24 4:42 ` Michael Ellerman
2015-02-23 20:44 ` [PATCH v2] " Nishanth Aravamudan
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