[PATCH kernel 5/5] powerpc/eeh: Remove unnecessary node from pci_dn

[Andrew Donnellan]

On 23/08/17 20:19, Alexey Kardashevskiy wrote:
> The pci_dn struct caches a OF device node pointer in order to access
> the "ibm,loc-code" property when EEH is recovering.
> 
> However, when this happens in eeh_dev_check_failure(), we also have
> a pci_dev pointer which should have a valid pointer to the device node
> when pci_dn has one (both pointers are not NULL for physical functions
> and are NULL for virtual functions).
> 
> This removes the node pointer from the pci_dn struct and used pdev
> in eeh_dev_check_failure() instead.
> 
> This changes pci_remove_device_node_info() to look for a parent of
> the node being removed, just like pci_add_device_node_info() does when it
> references the parent node.
> 
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

> ---
>   arch/powerpc/include/asm/pci-bridge.h | 1 -
>   arch/powerpc/kernel/eeh.c             | 9 +++++----
>   arch/powerpc/kernel/pci_dn.c          | 8 +++++---
>   3 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
> index 56c67d3f0108..0b8aa1fe2d5f 100644
> --- a/arch/powerpc/include/asm/pci-bridge.h
> +++ b/arch/powerpc/include/asm/pci-bridge.h
> @@ -195,7 +195,6 @@ struct pci_dn {
>   	struct  pci_dn *parent;
>   	struct  pci_controller *phb;	/* for pci devices */
>   	struct	iommu_table_group *table_group;	/* for phb's or bridges */
> -	struct	device_node *node;	/* back-pointer to the device_node */
>   
>   	int	pci_ext_config_space;	/* for pci devices */
>   
> diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
> index c877014d11ce..2c926029adbe 100644
> --- a/arch/powerpc/kernel/eeh.c
> +++ b/arch/powerpc/kernel/eeh.c
> @@ -435,7 +435,7 @@ int eeh_dev_check_failure(struct eeh_dev *edev)
>   	int ret;
>   	int active_flags = (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE);
>   	unsigned long flags;
> -	struct pci_dn *pdn;
> +	struct device_node *dn;
>   	struct pci_dev *dev;
>   	struct eeh_pe *pe, *parent_pe, *phb_pe;
>   	int rc = 0;
> @@ -493,9 +493,10 @@ int eeh_dev_check_failure(struct eeh_dev *edev)
>   	if (pe->state & EEH_PE_ISOLATED) {
>   		pe->check_count++;
>   		if (pe->check_count % EEH_MAX_FAILS == 0) {
> -			pdn = eeh_dev_to_pdn(edev);
> -			if (pdn->node)
> -				location = of_get_property(pdn->node, "ibm,loc-code", NULL);
> +			dn = pci_device_to_OF_node(dev);
> +			if (dn)
> +				location = of_get_property(dn, "ibm,loc-code",
> +						NULL);
>   			printk(KERN_ERR "EEH: %d reads ignored for recovering device at "
>   				"location=%s driver=%s pci addr=%s\n",
>   				pe->check_count,
> diff --git a/arch/powerpc/kernel/pci_dn.c b/arch/powerpc/kernel/pci_dn.c
> index 0256372b72de..0e395afbf0f4 100644
> --- a/arch/powerpc/kernel/pci_dn.c
> +++ b/arch/powerpc/kernel/pci_dn.c
> @@ -293,7 +293,6 @@ struct pci_dn *pci_add_device_node_info(struct pci_controller *hose,
>   	if (pdn == NULL)
>   		return NULL;
>   	dn->data = pdn;
> -	pdn->node = dn;
>   	pdn->phb = hose;
>   #ifdef CONFIG_PPC_POWERNV
>   	pdn->pe_number = IODA_INVALID_PE;
> @@ -342,6 +341,7 @@ EXPORT_SYMBOL_GPL(pci_add_device_node_info);
>   void pci_remove_device_node_info(struct device_node *dn)
>   {
>   	struct pci_dn *pdn = dn ? PCI_DN(dn) : NULL;
> +	struct device_node *parent;
>   #ifdef CONFIG_EEH
>   	struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
>   
> @@ -354,8 +354,10 @@ void pci_remove_device_node_info(struct device_node *dn)
>   
>   	WARN_ON(!list_empty(&pdn->child_list));
>   	list_del(&pdn->list);
> -	if (pdn->parent)
> -		of_node_put(pdn->parent->node);
> +
> +	parent = of_get_parent(dn);
> +	if (parent)
> +		of_node_put(parent);
>   
>   	dn->data = NULL;
>   	kfree(pdn);
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited