Re: [PATCH v10 13/18] powerpc/pci: Delay populating pdn

[Daniel Axtens <dja@axtens.net>]

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Hi,

mpe merged this to his next yesterday, and my nightly scripts picked up
the following cppcheck warning:

[arch/powerpc/kernel/pci_dn.c:486]: (error) Memory leak: pdn

That goes to the following function:

static void *add_pdn(struct device_node *dn, void *data)
{
        struct pci_controller *hose = data;
        struct pci_dn *pdn;

        pdn = pci_add_device_node_info(hose, dn);
        if (!pdn)
                return ERR_PTR(-ENOMEM);

        return NULL;
}

It looks like this is just called in pci_devs_phb_init_dynamic:

        /* Update dn->phb ptrs for new phb and children devices */
        pci_traverse_device_nodes(dn, add_pdn, phb);

So my understanding is that this isn't a real memory leak but just
cppcheck getting confused.

Gavin, can you confirm that?

Regards,
Daniel

Gavin Shan <gwshan@linux.vnet.ibm.com> writes:

> The pdn (struct pci_dn) instances are allocated from memblock or
> bootmem when creating PCI controller (hoses) in setup_arch(). PCI
> hotplug, which will be supported by proceeding patches, releases
> PCI device nodes and their corresponding pdn on unplugging event.
> The memory chunks for pdn instances allocated from memblock or
> bootmem are hard to reused after being released.
>
> This delays creating pdn by pci_devs_phb_init() from setup_arch()
> to core_initcall() so that they are allocated from slab. The memory
> consumed by pdn can be released to system without problem during
> PCI unplugging time. It indicates that pci_dn is unavailable in
> setup_arch() and the the fixup on pdn (like AGP's) can't be carried
> out that time. We have to do that in pcibios_root_bridge_prepare()
> on maple/pasemi/powermac platforms where/when the pdn is available.
> pcibios_root_bridge_prepare is called from subsys_initcall() which
> is executed after core_initcall() so the code flow does not change.
>
> At the mean while, the EEH device is created when pdn is populated,
> meaning pdn and EEH device have same life cycle. In turn, we needn't
> call eeh_dev_init() to create EEH device explicitly.
>
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
>  arch/powerpc/include/asm/eeh.h         |  2 +-
>  arch/powerpc/include/asm/ppc-pci.h     |  2 --
>  arch/powerpc/kernel/eeh_dev.c          | 17 +++------------
>  arch/powerpc/kernel/pci_dn.c           | 23 ++++++++++++++++----
>  arch/powerpc/platforms/maple/pci.c     | 34 ++++++++++++++++++------------
>  arch/powerpc/platforms/pasemi/pci.c    |  3 ---
>  arch/powerpc/platforms/powermac/pci.c  | 38 +++++++++++++++++++++-------------
>  arch/powerpc/platforms/powernv/pci.c   |  3 ---
>  arch/powerpc/platforms/pseries/setup.c |  6 +-----
>  9 files changed, 69 insertions(+), 59 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
> index fb9f376..8721580 100644
> --- a/arch/powerpc/include/asm/eeh.h
> +++ b/arch/powerpc/include/asm/eeh.h
> @@ -274,7 +274,7 @@ void eeh_pe_restore_bars(struct eeh_pe *pe);
>  const char *eeh_pe_loc_get(struct eeh_pe *pe);
>  struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe);
>  
> -void *eeh_dev_init(struct pci_dn *pdn, void *data);
> +struct eeh_dev *eeh_dev_init(struct pci_dn *pdn);
>  void eeh_dev_phb_init_dynamic(struct pci_controller *phb);
>  int eeh_init(void);
>  int __init eeh_ops_register(struct eeh_ops *ops);
> diff --git a/arch/powerpc/include/asm/ppc-pci.h b/arch/powerpc/include/asm/ppc-pci.h
> index 8753e4e..0f73de0 100644
> --- a/arch/powerpc/include/asm/ppc-pci.h
> +++ b/arch/powerpc/include/asm/ppc-pci.h
> @@ -39,8 +39,6 @@ void *pci_traverse_device_nodes(struct device_node *start,
>  void *traverse_pci_dn(struct pci_dn *root,
>  		      void *(*fn)(struct pci_dn *, void *),
>  		      void *data);
> -
> -extern void pci_devs_phb_init(void);
>  extern void pci_devs_phb_init_dynamic(struct pci_controller *phb);
>  
>  /* From rtas_pci.h */
> diff --git a/arch/powerpc/kernel/eeh_dev.c b/arch/powerpc/kernel/eeh_dev.c
> index 7815095..d6b2ca7 100644
> --- a/arch/powerpc/kernel/eeh_dev.c
> +++ b/arch/powerpc/kernel/eeh_dev.c
> @@ -44,14 +44,13 @@
>  /**
>   * eeh_dev_init - Create EEH device according to OF node
>   * @pdn: PCI device node
> - * @data: PHB
>   *
>   * It will create EEH device according to the given OF node. The function
>   * might be called by PCI emunation, DR, PHB hotplug.
>   */
> -void *eeh_dev_init(struct pci_dn *pdn, void *data)
> +struct eeh_dev *eeh_dev_init(struct pci_dn *pdn)
>  {
> -	struct pci_controller *phb = data;
> +	struct pci_controller *phb = pdn->phb;
>  	struct eeh_dev *edev;
>  
>  	/* Allocate EEH device */
> @@ -69,7 +68,7 @@ void *eeh_dev_init(struct pci_dn *pdn, void *data)
>  	INIT_LIST_HEAD(&edev->list);
>  	INIT_LIST_HEAD(&edev->rmv_list);
>  
> -	return NULL;
> +	return edev;
>  }
>  
>  /**
> @@ -81,16 +80,8 @@ void *eeh_dev_init(struct pci_dn *pdn, void *data)
>   */
>  void eeh_dev_phb_init_dynamic(struct pci_controller *phb)
>  {
> -	struct pci_dn *root = phb->pci_data;
> -
>  	/* EEH PE for PHB */
>  	eeh_phb_pe_create(phb);
> -
> -	/* EEH device for PHB */
> -	eeh_dev_init(root, phb);
> -
> -	/* EEH devices for children OF nodes */
> -	traverse_pci_dn(root, eeh_dev_init, phb);
>  }
>  
>  /**
> @@ -106,8 +97,6 @@ static int __init eeh_dev_phb_init(void)
>  	list_for_each_entry_safe(phb, tmp, &hose_list, list_node)
>  		eeh_dev_phb_init_dynamic(phb);
>  
> -	pr_info("EEH: devices created\n");
> -
>  	return 0;
>  }
>  
> diff --git a/arch/powerpc/kernel/pci_dn.c b/arch/powerpc/kernel/pci_dn.c
> index ecdccce..9cbf95a 100644
> --- a/arch/powerpc/kernel/pci_dn.c
> +++ b/arch/powerpc/kernel/pci_dn.c
> @@ -209,8 +209,7 @@ struct pci_dn *add_dev_pci_data(struct pci_dev *pdev)
>  		}
>  
>  		/* Create the EEH device for the VF */
> -		eeh_dev_init(pdn, pci_bus_to_host(pdev->bus));
> -		edev = pdn_to_eeh_dev(pdn);
> +		edev = eeh_dev_init(pdn);
>  		BUG_ON(!edev);
>  		edev->physfn = pdev;
>  	}
> @@ -289,8 +288,11 @@ struct pci_dn *pci_add_device_node_info(struct pci_controller *hose,
>  	const __be32 *regs;
>  	struct device_node *parent;
>  	struct pci_dn *pdn;
> +#ifdef CONFIG_EEH
> +	struct eeh_dev *edev;
> +#endif
>  
> -	pdn = zalloc_maybe_bootmem(sizeof(*pdn), GFP_KERNEL);
> +	pdn = kzalloc(sizeof(*pdn), GFP_KERNEL);
>  	if (pdn == NULL)
>  		return NULL;
>  	dn->data = pdn;
> @@ -319,6 +321,15 @@ struct pci_dn *pci_add_device_node_info(struct pci_controller *hose,
>  	/* Extended config space */
>  	pdn->pci_ext_config_space = (type && of_read_number(type, 1) == 1);
>  
> +	/* Create EEH device */
> +#ifdef CONFIG_EEH
> +	edev = eeh_dev_init(pdn);
> +	if (!edev) {
> +		kfree(pdn);
> +		return NULL;
> +	}
> +#endif
> +
>  	/* Attach to parent node */
>  	INIT_LIST_HEAD(&pdn->child_list);
>  	INIT_LIST_HEAD(&pdn->list);
> @@ -504,15 +515,19 @@ void pci_devs_phb_init_dynamic(struct pci_controller *phb)
>   * pci device found underneath.  This routine runs once,
>   * early in the boot sequence.
>   */
> -void __init pci_devs_phb_init(void)
> +static int __init pci_devs_phb_init(void)
>  {
>  	struct pci_controller *phb, *tmp;
>  
>  	/* This must be done first so the device nodes have valid pci info! */
>  	list_for_each_entry_safe(phb, tmp, &hose_list, list_node)
>  		pci_devs_phb_init_dynamic(phb);
> +
> +	return 0;
>  }
>  
> +core_initcall(pci_devs_phb_init);
> +
>  static void pci_dev_pdn_setup(struct pci_dev *pdev)
>  {
>  	struct pci_dn *pdn;
> diff --git a/arch/powerpc/platforms/maple/pci.c b/arch/powerpc/platforms/maple/pci.c
> index a923230..a2f89e6 100644
> --- a/arch/powerpc/platforms/maple/pci.c
> +++ b/arch/powerpc/platforms/maple/pci.c
> @@ -568,6 +568,26 @@ void maple_pci_irq_fixup(struct pci_dev *dev)
>  	DBG(" <- maple_pci_irq_fixup\n");
>  }
>  
> +static int maple_pci_root_bridge_prepare(struct pci_host_bridge *bridge)
> +{
> +	struct pci_controller *hose = pci_bus_to_host(bridge->bus);
> +	struct device_node *np, *child;
> +
> +	if (hose != u3_agp)
> +		return 0;
> +
> +	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
> +	 * assume there is no P2P bridge on the AGP bus, which should be a
> +	 * safe assumptions hopefully.
> +	 */
> +	np = hose->dn;
> +	PCI_DN(np)->busno = 0xf0;
> +	for_each_child_of_node(np, child)
> +		PCI_DN(child)->busno = 0xf0;
> +
> +	return 0;
> +}
> +
>  void __init maple_pci_init(void)
>  {
>  	struct device_node *np, *root;
> @@ -605,19 +625,7 @@ void __init maple_pci_init(void)
>  	if (ht && maple_add_bridge(ht) != 0)
>  		of_node_put(ht);
>  
> -	/* Setup the linkage between OF nodes and PHBs */ 
> -	pci_devs_phb_init();
> -
> -	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
> -	 * assume there is no P2P bridge on the AGP bus, which should be a
> -	 * safe assumptions hopefully.
> -	 */
> -	if (u3_agp) {
> -		struct device_node *np = u3_agp->dn;
> -		PCI_DN(np)->busno = 0xf0;
> -		for (np = np->child; np; np = np->sibling)
> -			PCI_DN(np)->busno = 0xf0;
> -	}
> +	ppc_md.pcibios_root_bridge_prepare = maple_pci_root_bridge_prepare;
>  
>  	/* Tell pci.c to not change any resource allocations.  */
>  	pci_add_flags(PCI_PROBE_ONLY);
> diff --git a/arch/powerpc/platforms/pasemi/pci.c b/arch/powerpc/platforms/pasemi/pci.c
> index f3a68a0..10c4e8f 100644
> --- a/arch/powerpc/platforms/pasemi/pci.c
> +++ b/arch/powerpc/platforms/pasemi/pci.c
> @@ -229,9 +229,6 @@ void __init pas_pci_init(void)
>  			of_node_get(np);
>  
>  	of_node_put(root);
> -
> -	/* Setup the linkage between OF nodes and PHBs */
> -	pci_devs_phb_init();
>  }
>  
>  void __iomem *pasemi_pci_getcfgaddr(struct pci_dev *dev, int offset)
> diff --git a/arch/powerpc/platforms/powermac/pci.c b/arch/powerpc/platforms/powermac/pci.c
> index 59ab16f..6e06c3b 100644
> --- a/arch/powerpc/platforms/powermac/pci.c
> +++ b/arch/powerpc/platforms/powermac/pci.c
> @@ -878,6 +878,29 @@ void pmac_pci_irq_fixup(struct pci_dev *dev)
>  #endif /* CONFIG_PPC32 */
>  }
>  
> +#ifdef CONFIG_PPC64
> +static int pmac_pci_root_bridge_prepare(struct pci_host_bridge *bridge)
> +{
> +	struct pci_controller *hose = pci_bus_to_host(bridge->bus);
> +	struct device_node *np, *child;
> +
> +	if (hose != u3_agp)
> +		return 0;
> +
> +	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
> +	 * assume there is no P2P bridge on the AGP bus, which should be a
> +	 * safe assumptions for now. We should do something better in the
> +	 * future though
> +	 */
> +	np = hose->dn;
> +	PCI_DN(np)->busno = 0xf0;
> +	for_each_child_of_node(np, child)
> +		PCI_DN(child)->busno = 0xf0;
> +
> +	return 0;
> +}
> +#endif /* CONFIG_PPC64 */
> +
>  void __init pmac_pci_init(void)
>  {
>  	struct device_node *np, *root;
> @@ -914,20 +937,7 @@ void __init pmac_pci_init(void)
>  	if (ht && pmac_add_bridge(ht) != 0)
>  		of_node_put(ht);
>  
> -	/* Setup the linkage between OF nodes and PHBs */
> -	pci_devs_phb_init();
> -
> -	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
> -	 * assume there is no P2P bridge on the AGP bus, which should be a
> -	 * safe assumptions for now. We should do something better in the
> -	 * future though
> -	 */
> -	if (u3_agp) {
> -		struct device_node *np = u3_agp->dn;
> -		PCI_DN(np)->busno = 0xf0;
> -		for (np = np->child; np; np = np->sibling)
> -			PCI_DN(np)->busno = 0xf0;
> -	}
> +	ppc_md.pcibios_root_bridge_prepare = pmac_pci_root_bridge_prepare;
>  	/* pmac_check_ht_link(); */
>  
>  #else /* CONFIG_PPC64 */
> diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
> index b1ee631..0f1b8bf 100644
> --- a/arch/powerpc/platforms/powernv/pci.c
> +++ b/arch/powerpc/platforms/powernv/pci.c
> @@ -816,9 +816,6 @@ void __init pnv_pci_init(void)
>  	for_each_compatible_node(np, NULL, "ibm,ioda2-npu-phb")
>  		pnv_pci_init_npu_phb(np);
>  
> -	/* Setup the linkage between OF nodes and PHBs */
> -	pci_devs_phb_init();
> -
>  	/* Configure IOMMU DMA hooks */
>  	set_pci_dma_ops(&dma_iommu_ops);
>  }
> diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
> index 9883bc7..4eada28 100644
> --- a/arch/powerpc/platforms/pseries/setup.c
> +++ b/arch/powerpc/platforms/pseries/setup.c
> @@ -265,11 +265,8 @@ static int pci_dn_reconfig_notifier(struct notifier_block *nb, unsigned long act
>  	case OF_RECONFIG_ATTACH_NODE:
>  		parent = of_get_parent(np);
>  		pdn = parent ? PCI_DN(parent) : NULL;
> -		if (pdn) {
> -			/* Create pdn and EEH device */
> +		if (pdn)
>  			pci_add_device_node_info(pdn->phb, np);
> -			eeh_dev_init(PCI_DN(np), pdn->phb);
> -		}
>  
>  		of_node_put(parent);
>  		break;
> @@ -492,7 +489,6 @@ static void __init find_and_init_phbs(void)
>  	}
>  
>  	of_node_put(root);
> -	pci_devs_phb_init();
>  
>  	/*
>  	 * PCI_PROBE_ONLY and PCI_REASSIGN_ALL_BUS can be set via properties
> -- 
> 2.1.0
>
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