From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e32.co.us.ibm.com (e32.co.us.ibm.com [32.97.110.150]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 37FFC1A0E06 for ; Fri, 20 Feb 2015 05:41:12 +1100 (AEDT) Received: from /spool/local by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 19 Feb 2015 11:41:09 -0700 Received: from b03cxnp07028.gho.boulder.ibm.com (b03cxnp07028.gho.boulder.ibm.com [9.17.130.15]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id BA0CC3E4003F for ; Thu, 19 Feb 2015 11:41:08 -0700 (MST) Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by b03cxnp07028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t1JIdanK21954578 for ; Thu, 19 Feb 2015 11:39:36 -0700 Received: from d03av05.boulder.ibm.com (localhost [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t1JIf5KX020632 for ; Thu, 19 Feb 2015 11:41:05 -0700 Date: Thu, 19 Feb 2015 10:41:03 -0800 From: Nishanth Aravamudan To: Michael Ellerman Subject: [PATCH] pseries/iommu: remove iommu device references via bus notifier Message-ID: <20150219184103.GB13745@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alexey Kardashevskiy , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Cc: stable@kernel.org (3.13+) 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);